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1

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.

McLaughlin-Drubin, Margaret E.; Munger, Karl

2009-01-01

2

Anchorage-Independent Transcription of the Cyclin A Gene Induced by the E7 Oncoprotein of Human Papillomavirus Type 16  

Microsoft Academic Search

To develop an experimental model for E7-mediated anchorage-independent growth, we studied the ability of E7-expressing NIH 3T3 subclones to enter S phase when they were cultured in suspension. We found that expression of E7 prevents the inhibition of cyclin E-associated kinase and also triggers activation of cyclin A gene expression in suspension cells. A point mutation in the amino terminus

ALMUT SCHULZE; BORIS MANNHARDT; KARIN ZERFASS-THOME; WERNER ZWERSCHKE; PIDDER JANSEN-DURR

1998-01-01

3

Oncoprotein E7 from Beta Human Papillomavirus 38 Induces Formation of an Inhibitory Complex for a Subset of p53-Regulated Promoters.  

PubMed

Our previous studies on cutaneous beta human papillomavirus 38 (HPV38) E6 and E7 oncoproteins highlighted a novel activity of I?B kinase beta (IKK?) in the nucleus of human keratinocytes, where it phosphorylates and stabilizes ?Np73?, an antagonist of p53/p73 functions. Here, we further characterize the role of the IKK? nuclear form. We show that IKK? nuclear translocation and ?Np73? accumulation are mediated mainly by HPV38 E7 oncoprotein. Chromatin immunoprecipitation (ChIP)/Re-ChIP experiments showed that ?Np73? and IKK? are part, together with two epigenetic enzymes DNA methyltransferase 1 (DNMT1) and the enhancer of zeste homolog 2 (EZH2), of a transcriptional regulatory complex that inhibits the expression of some p53-regulated genes, such as PIG3. Recruitment to the PIG3 promoter of EZH2 and DNMT1 resulted in trimethylation of histone 3 on lysine 27 and in DNA methylation, respectively, both events associated with gene expression silencing. Decreases in the intracellular levels of HPV38 E7 or ?Np73? strongly affected the recruitment of the inhibitory transcriptional complex to the PIG3 promoter, with consequent restoration of p53-regulated gene expression. Finally, the ?Np73?/IKK?/DNMT1/EZH2 complex appears to bind a subset of p53-regulated promoters. In fact, the complex is efficiently recruited to several promoters of genes encoding proteins involved in DNA repair and apoptosis, whereas it does not influence the expression of the prosurvival factor Survivin. In summary, our data show that HPV38 via E7 protein promotes the formation of a multiprotein complex that negatively regulates the expression of several p53-regulated genes. PMID:24006445

Saidj, Djamel; Cros, Marie-Pierre; Hernandez-Vargas, Hector; Guarino, Francesca; Sylla, Bakary S; Tommasino, Massimo; Accardi, Rosita

2013-09-04

4

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

5

Hypoxia inducible factor-1 alpha expression is increased in infected positive HPV16 DNA oral squamous cell carcinoma and positively associated with HPV16 E7 oncoprotein  

PubMed Central

Background There is increasing evidence for the role of High Risk (HR) Human PapillomaVirus (HPV) in the pathogenesis of Oral Squamous Cell Carcinoma (OSCC). The E6 and E7 oncogenes from HR HPVs are responsible for the deregulation of p53 and pRB proteins involved in cell cycle and apoptotic pathways. In cell lines experiments, the HPV E7 protein seems to be able to enhance Hypoxia Inducible Factor-1 alpha (HIF-1?) activity, normally involved in the response to hypoxia and able to enhance angiogenesis. Results We studied tumor specimens from 62 OSCC; a higher prevalence of tumors in TNM stage II and also in pT2 class between OSCC infected positive HPV16 DNA than non-infected ones was observed. HIF-1? positivity was detected throughout the analysed fields, not associated with areas of necrosis and also observed in cells immediately adjacent to blood vessels. A significant increase in mean values of the HIF-1? labeling indexes was observed for pT1-T2, as well for stage I-II, in the infected positive HPV16 DNA tumors than non-infected ones. HIF-1? and HPV16 E7 labeling indexes showed a significantly positive correlation which suggested a positive association between HPV16 E7 and HIF-1? expression. Conclusions In our specimens HIF-1? immunoreactivity hints for an O2-independent regulatory mechanism in infected positive HPV16 DNA tumors, especially for pT1-T2 and stage I-II tumors, suggesting a very early involvement in the development of HPV-induced OSCC. HIF-1? and HPV16 E7 labeling indexes suggest also a positive association between the two proteins in infected positive HPV16 DNA OSCC.

2011-01-01

6

Modulation of type M2 pyruvate kinase activity by the human papillomavirus type 16 E7 oncoprotein  

PubMed Central

We report here that the E7 oncoprotein encoded by the oncogenic human papillomavirus (HPV) type 16 binds to the glycolytic enzyme type M2 pyruvate kinase (M2-PK). M2-PK occurs in a tetrameric form with a high affinity to its substrate phosphoenolpyruvate and a dimeric form with a low affinity to phosphoenolpyruvate, and the transition between both conformations regulates the glycolytic flux in tumor cells. The glycolytic intermediate fructose 1,6-bisphosphate induces the reassociation of the dimeric to the tetrameric form of M2-PK. The expression of E7 in an experimental cell line shifts the equilibrium to the dimeric state despite a significant increase in the fructose 1,6-bisphosphate levels. Investigations of HPV-16 E7 mutants and the nononcogenic HPV-11 subtype suggest that the interaction of HPV-16 E7 with M2-PK may be linked to the transforming potential of the viral oncoprotein.

Zwerschke, Werner; Mazurek, Sybille; Massimi, Paola; Banks, Lawrence; Eigenbrodt, Erich; Jansen-Durr, Pidder

1999-01-01

7

Detection of Human Papillomavirus Type 18 E7 Oncoprotein in Cervical Smears: a Feasibility Study  

PubMed Central

Persistent infections by high-risk human papillomaviruses (HPVs) are the main etiological factor for cervical cancer, and expression of HPV E7 oncoproteins was suggested to be a potential marker for tumor progression. The objective of this study was to generate new reagents for the detection of the HPV18 E7 oncoprotein in cervical smears. Rabbit monoclonal antibodies against recombinant E7 protein of HPV type 18 (HPV18) were generated and characterized using Western blotting, epitope mapping, indirect immunofluorescence, and immunohistochemistry. One clone specifically recognizing HPV18 E7 was used for the development of a sandwich enzyme-linked immunosorbent assay (ELISA). The assay was validated using recombinant E7 proteins of various HPV types and lysates from E7-positive cervical carcinoma cells. A total of 14 HPV18 DNA-positive cervical swab specimens and 24 HPV DNA-negative-control specimens were used for the determination of E7 protein levels by the newly established sandwich ELISA. On the basis of the average absorbance values obtained from all 24 negative controls, a cutoff above which a clinical sample can be judged E7 positive was established. Significant E7 signals 6- to 30-fold over background were found in 7 out of 14 abnormal HPV18 DNA-positive cervical smear specimens. This feasibility study demonstrates for the first time that HPV18 E7 oncoprotein can be detected in cervical smears.

Ehehalt, Daniela; Lener, Barbara; Pircher, Haymo; Dreier, Kerstin; Pfister, Heiko; Kaufmann, Andreas M.; Frangini, Sergio; Ressler, Sigrun; Muller-Holzner, Elisabeth; Schmitt, Markus; Hofler, Daniela; Rostek, Ursula; Kaiser, Andreas; Widschwendter, Andreas; Zwerschke, Werner

2012-01-01

8

Detection of human papillomavirus type 18 E7 oncoprotein in cervical smears: a feasibility study.  

PubMed

Persistent infections by high-risk human papillomaviruses (HPVs) are the main etiological factor for cervical cancer, and expression of HPV E7 oncoproteins was suggested to be a potential marker for tumor progression. The objective of this study was to generate new reagents for the detection of the HPV18 E7 oncoprotein in cervical smears. Rabbit monoclonal antibodies against recombinant E7 protein of HPV type 18 (HPV18) were generated and characterized using Western blotting, epitope mapping, indirect immunofluorescence, and immunohistochemistry. One clone specifically recognizing HPV18 E7 was used for the development of a sandwich enzyme-linked immunosorbent assay (ELISA). The assay was validated using recombinant E7 proteins of various HPV types and lysates from E7-positive cervical carcinoma cells. A total of 14 HPV18 DNA-positive cervical swab specimens and 24 HPV DNA-negative-control specimens were used for the determination of E7 protein levels by the newly established sandwich ELISA. On the basis of the average absorbance values obtained from all 24 negative controls, a cutoff above which a clinical sample can be judged E7 positive was established. Significant E7 signals 6- to 30-fold over background were found in 7 out of 14 abnormal HPV18 DNA-positive cervical smear specimens. This feasibility study demonstrates for the first time that HPV18 E7 oncoprotein can be detected in cervical smears. PMID:22135254

Ehehalt, Daniela; Lener, Barbara; Pircher, Haymo; Dreier, Kerstin; Pfister, Heiko; Kaufmann, Andreas M; Frangini, Sergio; Ressler, Sigrun; Müller-Holzner, Elisabeth; Schmitt, Markus; Höfler, Daniela; Rostek, Ursula; Kaiser, Andreas; Widschwendter, Andreas; Zwerschke, Werner; Jansen-Dürr, Pidder

2011-11-30

9

Mice immunization with live lactococci displaying a surface anchored HPV16 E7 oncoprotein  

Microsoft Academic Search

E7 oncoprotein of human papillomavirus-16 (HPV-16) is constitutively produced in cervical cancer (CxCa) and is a good candidate for the design of therapeutic vaccines. In this work, the nisin-controlled expression system was used to display the E7 protein at the cell surface of the food-grade Gram-positive bacterium Lactococcus lactis. An efficient cell wall anchoring of E7 was obtained. Intranasal administration

Naima G Cortes-Perez; Luis G Bermúdez-Humarán; Yves Le Loir; Cristina Rodriguez-Padilla; Alexandra Gruss; Odila Saucedo-Cárdenas; Philippe Langella; Roberto Montes-de-Oca-Luna

2003-01-01

10

DNA vaccines against the human papillomavirus type 16 E6 or E7 oncoproteins  

Microsoft Academic Search

DNA vaccines expressing the E6 or E7 oncoproteins of human papilloma virus type 16 (HPV-16) in either their wild-type form or fused to sequences that affect intracellular trafficking were tested for induction of protective immunity against tumor cell challenge in two models based on BALB\\/c and C57Bl\\/6 mice. The DNA vaccines to E7 gave uniformly disappointing results, while the DNA

Anthony P Wlazlo; Hongying Deng; Wynetta Giles-Davis; Hildegund C J Ertl; Hildegund CJ Ertl

2004-01-01

11

Generation and characterization of monoclonal antibodies against the E6 and E7 oncoproteins of HPV.  

PubMed

Generation of three monoclonal antibodies (MAbs) to the major oncoproteins of human papillomavirus (HPV) was accomplished by an intense prime/boost regimen. Mice were primed with expression vectors expressing either the E6 or E7 oncoproteins of HPV-16 followed by boosting with a vaccinia virus construct and a replication-defective E1-deleted adenoviral recombinant of the human strain 5, and last, with baculovirus-derived HPV-16 E6 and E7 proteins in incomplete Freunds' adjuvant. Splenocytes were then fused with a myeloma cell line. The vaccination protocol generated one anti-E7 MAb of the IgM isotype and two anti-E6 MAbs of the IgG1 subisotype. The MAbs were tested for functionality in standard laboratory assays and found to detect the E6 and E7 proteins, respectively. The E7 MAb cross-reacted with the HPV-1a E7 oncoprotein. The binding sites of the MAbs were mapped to defined regions of each viral protein. PMID:11604112

Wlazlo, A P; Giles-Davis, W; Clements, A; Struble, G; Marmorstein, R; Ertl, H C

2001-08-01

12

Intranasal Immunization with synthetic peptides corresponding to the E6 and E7 oncoproteins of Human Papillomavirus type 16 induces systemic and mucosal cellular immune responses and tumor protection  

PubMed Central

The E6 and E7 oncoproteins of the high-risk HPV type16 represent ideal targets for HPV vaccine development, they being consistently expressed in cervical cancer lesions. Since HPV-16 is primarily transmitted through genital mucosal route, mucosal immune responses constitute an essential feature for vaccination strategies against HPV-associated lesions. We present here evidence showing that mucosal immunization of mice by the intranasal route with a mixture of peptides E744–62 and E643–57 from the E7 and E6 oncoproteins of HPV-16, respectively, using a mutant cholera toxin adjuvant (CT-2*), primed strong antigen-specific cellular immune responses in systemic and mucosal tissues. Significant levels of IFN-? production by both CD4 and CD8 cells were observed along with CTL responses that were effective against both peptide-pulsed targets as well as syngeneic tumor cells (TC-1) expressing the cognate E6 and E7 proteins. Furthermore, mice immunized with the peptide mixture and CT-2* effectively resisted TC-1 tumor challenge. These results together with our earlier observations that T cell responses to these peptides correlate with recurrence-free survival in women after ablative treatment for HPV-associated cervical intraepithelial neoplasia, support the potential of these E6 and E7 peptides for inclusion in vaccine formulations.

Manuri, Pallavi R.; Nehete, Bharti; Nehete, Pramod N.; Reisenauer, Rose; Wardell, Seth; Courtney, Amy N.; Gambhira, Ratish; Lomada, Dakshyani; Chopra, Ashok K.; Sastry, K. Jagannadha

2007-01-01

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

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

15

DNA vaccines against the human papillomavirus type 16 E6 or E7 oncoproteins.  

PubMed

DNA vaccines expressing the E6 or E7 oncoproteins of human papilloma virus type 16 (HPV-16) in either their wild-type form or fused to sequences that affect intracellular trafficking were tested for induction of protective immunity against tumor cell challenge in two models based on BALB/c and C57Bl/6 mice. The DNA vaccines to E7 gave uniformly disappointing results, while the DNA vaccine that expressed E6 linked to a viral leader sequence protected BALB/c mice against tumor cell challenge given before or after vaccination. The efficacy of this vaccine could be enhanced by a DNA vector prime/viral vector boost regimen. In contrast, priming of mice with the DNA vaccines to E7 reduced the efficacy of a viral vector expressing the same antigen. PMID:15118761

Wlazlo, Anthony P; Deng, Hongying; Giles-Davis, Wynetta; Ertl, Hildegund C J

2004-06-01

16

The role of human papillomavirus type 16 E6/E7 oncoproteins in cervical epithelial-mesenchymal transition and carcinogenesis.  

PubMed

Cervical cancer is the most common malignancy in females worldwide. This study investigated the prevalence of the E6/E7 oncoproteins of human papillomavirus (HPV) type 16, which are important in fibroblast growth factor (FGF) 2- and 4-induced epithelial-mesenchymal transition (EMT) and cervical tumorigenesis. We investigated the functional interaction between HPV16 E6/E7-transfected Cx cells (CxWJ cells) and treatment with FGF2 and 4, according to the expression of ?-smooth muscle actin (?-SMA), vimentin and E-cadherin protein as well as cell growth and invasive ability. The results showed the upregulation of ?-SMA and vimentin and the downregulation of E-cadherin protein expression in CxWJ cells. HPV16 E6/E7 infection partially repressed proliferation, but not the invasive ability of FGF2 or FGF4 stimulation in cervical cancer cells (CxWJ cells). These data provide evidence of a functional interaction between HPV16 E6/E7 and FGFs 2 and 4, suggesting that cooperative stimulation of HPV E6/E7 and FGFs activated in human cervical cancer cells is required to completely overcome the oncogenic function associated with the development of cervical epithelial-mesenchymal transition and tumorigenesis. PMID:22740973

Cheng, Ya-Min; Chou, Cheng-Yang; Hsu, Yi-Chiang; Chen, Ming-Jenn; Wing, Lih-Yuh C

2011-12-01

17

Evaluation of HBs, HBc, and frCP Virus-Like Particles for Expression of Human Papillomavirus 16 E7 Oncoprotein Epitopes  

Microsoft Academic Search

Objectives: In an attempt to develop virus-like particles (VLPs) as experimental vaccine against human papilloma virus (HPV)-induced tumours, the HPV16 E7 oncoprotein epitopes spanning amino acid (aa) residues 35–98 were expressed on three proteins capable of VLP formation: hepatitis B virus (HBV) surface (HBs) and core (HBc) antigens, and RNA phage fr coats (frCP). Methods: The profile of immunoglobulin isotypes

Paul Pumpens; Raimundas Razanskas; Peter Pushko; Regina Renhof; Indulis Gusars; Dace Skrastina; Velta Ose; Galina Borisova; Irina Sominskaya; Ivars Petrovskis; Juris Jansons; Kestutis Sasnauskas

2002-01-01

18

The human papillomavirus-16 E7 oncoprotein exerts antiapoptotic effects via its physical interaction with the actin-binding protein gelsolin.  

PubMed

The oncoprotein E7 from human papillomavirus-16 (HPV-16 E7) plays a pivotal role in HPV postinfective carcinogenesis, and its physical interaction with host cell targets is essential to its activity. We identified a novel cellular partner for the viral oncoprotein: the actin-binding protein gelsolin (GSN), a key regulator of actin filament assembly and disassembly. In fact, biochemical analyses, generation of a 3D molecular interaction model and the use of specific HPV-16 E7 mutants provided clear cut evidence supporting the crucial role of HPV-16 E7 in affecting GSN integrity and function in human immortalized keratinocytes. Accordingly, functional analyses clearly suggested that stable HPV-16 E7 expression induced an imbalance between polymeric and monomeric actin in favor of the former. These events also lead to changes of cell cycle (increased S phase), to the inhibition of apoptosis and to the increase of cell survival. These results provide support to the hypotheses generated from the 3D molecular interaction model and encourage the design of small molecules hindering HPV-induced host cell reprogramming by specifically targeting HPV-16 E7-expressing cells. PMID:23729654

Mileo, Anna M; Abbruzzese, Claudia; Vico, Carmen; Bellacchio, Emanuele; Matarrese, Paola; Ascione, Barbara; Federico, Antonio; Della Bianca, Stefano; Mattarocci, Stefano; Malorni, Walter; Paggi, Marco G

2013-06-01

19

Human Papillomavirus Type 16 E7 oncoprotein engages but does not abrogate the mitotic spindle assembly checkpoint  

PubMed Central

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.

Yu, Yueyang; Munger, Karl

2012-01-01

20

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.

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

2011-01-01

21

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

PubMed

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

2010-10-23

22

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.

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

2010-01-01

23

Leaky Scanning Is the Predominant Mechanism for Translation of Human Papillomavirus Type 16 E7 Oncoprotein from E6/E7 Bicistronic mRNA  

PubMed Central

Human papillomaviruses (HPV) are unique in that they generate mRNAs that apparently can express multiple proteins from tandemly arranged open reading frames. The mechanisms by which this is achieved are uncertain and are at odds with the basic predictions of the scanning model for translation initiation. We investigated the unorthodox mechanism by which the E6 and E7 oncoproteins from human papillomavirus type 16 (HPV-16) can be translated from a single, bicistronic mRNA. The short E6 5? untranslated region (UTR) was shown to promote translation as efficiently as a UTR from Xenopus ?-globin. Insertion of a secondary structural element into the UTR inhibited both E6 and E7 expression, suggesting that E7 expression depends on ribosomal scanning from the 5? end of the mRNA. E7 translation was found to be cap dependent, but E6 was more dependent on capping and eIF4F activity than E7. Insertion of secondary structural elements at various points in the region upstream of E7 profoundly inhibited translation, indicating that scanning was probably continuous. Insertion of the E6 region between Renilla and firefly luciferase genes revealed little or no internal ribosomal entry site activity. However when E6 was located at the 5? end of the mRNA, it permitted over 100-fold-higher levels of downstream cistron translation than did the Renilla open reading frame. Internal AUGs in the E6 region with strong or intermediate Kozak sequence contexts were unable to inhibit E7 translation, but initiation at the E7 AUG was efficient and accurate. These data support a model in which E7 translation is facilitated by an extreme degree of leaky scanning, requiring the negotiation of 13 upstream AUGs. Ribosomal initiation complexes which fail to initiate at the E6 start codon can scan through to the E7 AUG without initiating translation, but competence to initiate is achieved once the E7 AUG is reached. These findings suggest that the E6 region of HPV-16 comprises features that sponsor both translation of the E6 protein and enhancement of translation at a downstream site.

Stacey, Simon N.; Jordan, Deborah; Williamson, Andrew J. K.; Brown, Michael; Coote, Joanna H.; Arrand, John R.

2000-01-01

24

Localisation of Human Papillomavirus 16 E7 Oncoprotein Changes with Cell Confluence  

PubMed Central

E7 is one of the best studied proteins of human papillomavirus type 16, largely because of its oncogenic potential linked to cervical cancer. Yet the sub-cellular location of E7 remains confounding, even though it has been shown to be able to shuttle between the nucleus and the cytoplasm. Here we show with immunocytochemistry that E7 proteins are located in the nucleus and cytoplasm in sub-confluent cells, but becomes cytoplasmic in confluent cells. The change in E7's location is independent of time in culture, cell division, cell cycle phase or cellular differentiation. Levels of E7 are also increased in confluent cells as determined by Western blotting. Our investigations have also uncovered how different analytical techniques influence the observation of where E7 is localised, highlighting the importance of technical choice in such analysis. Understanding the localisation of E7 will help us to better comprehend the function of E7 on its target proteins.

Laurson, Joanna; Raj, Kenneth

2011-01-01

25

Retinoblastoma-independent antiproliferative activity of novel intracellular antibodies against the E7 oncoprotein in HPV 16-positive cells  

PubMed Central

Background "High risk" Human Papillomavirus strains are the causative agents of the vast majority of carcinomas of the uterine cervix. In these tumors, the physical integration of the HPV genome is a frequent, though not invariable occurrence, but the constitutive expression of the E6 and E7 viral genes is always observed, suggesting key roles for the E6 and E7 oncoproteins in the process of malignant transformation. The "intracellular antibody" technology using recombinant antibodies in single-chain format offers the possibility of targeting a protein in its intracellular environment even at the level of definite domains thus representing a valuable strategy to "knock out" the function of specific proteins. Methods In this study, we investigate the in vitro activity of two single-chain antibody fragments directed against the "high-risk" HPV 16 E7 oncoprotein, scFv 43M2 and scFv 51. These scFvs were expressed by retroviral system in different cell compartments of the HPV16-positive SiHa cells, and cell proliferation was analyzed by Colony Formation Assay and EZ4U assay. The binding of these scFvs to E7, and their possible interference with the interaction between E7 and its main target, the tumor suppressor pRb protein, were then investigated by immunoassays, PepSet™technology and Surface Plasmon Resonance. Results The expression of the two scFvs in the nucleus and the endoplasmic reticulum of SiHa cells resulted in the selective growth inhibition of these cells. Analysis of binding showed that both scFvs bind E7 via distinct but overlapping epitopes not corresponding to the pRb binding site. Nevertheless, the binding of scFv 43M2 to E7 was inhibited by pRb in a non-competitive manner. Conclusions Based on the overall results, the observed inhibition of HPV-positive SiHa cells proliferation could be ascribed to an interaction between scFv and E7, involving non-pRb targets. The study paves the way for the employment of specific scFvs in immunotherapeutic approaches against the HPV-associated lesions.

2011-01-01

26

Activation of Src, Fyn and Yes non-receptor tyrosine kinases in keratinocytes expressing human papillomavirus (HPV) type 16 E7 oncoprotein  

PubMed Central

Background The Src family tyrosine kinases (SFK) are cellular regulatory proteins that influence cell adhesion, proliferation, invasion and survival during tumor development. Elevated activity of Src was associated with increased cell proliferation and invasivity in human papillomavirus (HPV)-associated malignancies; therefore, transduced human foreskin keratinocytes (HFK) were used to investigate whether SFK activation is a downstream effect of papillomaviral oncoproteins. Activation of ubiquitously expressed SFKs, namely Src, Yes and Fyn, was investigated in both proliferating and differentiating keratinocytes. Results In proliferating keratinocytes, Src, Yes and Fyn mRNA levels were not affected by HPV 16 E6 or E7 oncoproteins, while at the protein level as detected by western blot, the presence of both E6 and E7 resulted in substantial increase in Src and Yes expression, but did not alter the high constitutive level of Fyn. Phospo-kinase array revealed that all ubiquitously expressed SFKs are activated by phosphorylation in the presence of HPV 16 E7 oncoprotein. Keratinocyte differentiation led to increased Yes mRNA and protein levels in all transduced cell lines, while it did not influence the Src transcription but resulted in elevated Src protein level in HPV16 E7 expressing lines. Conclusions This study revealed that HPV 16 oncoproteins upregulate Src family kinases Src and Yes via posttranscriptional mechanisms. A further effect of HPV 16 E7 oncoprotein is to enhance the activating phosphorylation of SFKs expressed in keratinocytes.

2013-01-01

27

Delocalization of the Microtubule Motor Dynein from Mitotic Spindles by the Human Papillomavirus E7 Oncoprotein is Not Sufficient for Induction of Multipolar Mitoses  

PubMed Central

Dynein is a minus-end directed microtubule motor that transports numerous cargoes throughout the cell. During mitosis, dynein motor activity is necessary for the positioning of spindle microtubules and has also been implicated in inactivating the spindle assembly checkpoint. Mutations in dynein motor and/or accessory proteins are associated with human disease, including cancer, and the delocalization of dynein from mitotic spindles has been correlated with an increased incidence of multipolar spindle formation in some cancer cells that contain supernumerary centrosomes. The high-risk human papillomavirus type 16 (HPV16) E7 oncoprotein induces centrosome overduplication and has been shown to cause multipolar mitotic spindle formation, a diagnostic hallmark of HPV-associated neoplasias. Here we show that HPV16 E7 expression leads to an increased population of mitotic cells with dynein delocalized from the mitotic spindle. This function maps to sequences of HPV16 E7 that are distinct from the region necessary for centrosome overduplication. However, contrary to previous reports, we provide evidence that dynein delocalization by HPV16 E7 is neither necessary nor sufficient to cause the formation of multipolar mitoses.

Nguyen, Christine L.; McLaughlin-Drubin, Margaret E.; Munger, Karl

2008-01-01

28

Delocalization of the microtubule motor Dynein from mitotic spindles by the human papillomavirus E7 oncoprotein is not sufficient for induction of multipolar mitoses.  

PubMed

Dynein is a minus end-directed microtubule motor that transports numerous cargoes throughout the cell. During mitosis, dynein motor activity is necessary for the positioning of spindle microtubules and has also been implicated in inactivating the spindle assembly checkpoint. Mutations in dynein motor and/or accessory proteins are associated with human disease, including cancer, and the delocalization of dynein from mitotic spindles has been correlated with an increased incidence of multipolar spindle formation in some cancer cells that contain supernumerary centrosomes. The high-risk human papillomavirus type 16 (HPV16) E7 oncoprotein induces centrosome overduplication and has been shown to cause multipolar mitotic spindle formation, a diagnostic hallmark of HPV-associated neoplasias. Here, we show that HPV16 E7 expression leads to an increased population of mitotic cells with dynein delocalized from the mitotic spindle. This function maps to sequences of HPV16 E7 that are distinct from the region necessary for centrosome overduplication. However, contrary to previous reports, we provide evidence that dynein delocalization by HPV16 E7 is neither necessary nor sufficient to cause the formation of multipolar mitoses. PMID:18974113

Nguyen, Christine L; McLaughlin-Drubin, Margaret E; Münger, Karl

2008-11-01

29

The human papillomavirus type 16 E7 oncoprotein targets Myc-interacting zinc-finger protein-1.  

PubMed

We demonstrate that HPV-16 E7 forms a complex with Miz-1. UV-induced expression of the CDK-inhibitor p21(Cip1) and subsequent cell cycle arrest depends upon endogenous Miz-1 in HPV-negative C33A cervical cancer cells containing mutated p53. Transient expression of E7 in C33A inhibits UV-induced expression of p21(Cip1) and overcomes Miz-1-induced G1-phase arrest. The C-terminal E7?79LEDLL83-mutant with reduced Miz-1-binding capacity was impaired in its capability to repress p21(Cip1) expression; whereas the pRB-binding-deficient E7C24G-mutant inhibited p21(Cip1) expression similar to wild-type E7. Using ChIP, we demonstrate that endogenous E7 is bound to the endogenous p21(Cip1) core-promoter in CaSki cells and RNAi-mediated knock down of Miz-1 abrogates E7-binding to the p21(Cip1) promoter. Co-expression of E7 with Miz-1 inhibited Miz-1-induced p21(Cip1) expression from the minimal-promoter via Miz-1 DNA-binding sites. Co-expression of E7?79LEDLL83 did not inhibit Miz-1-induced p21(Cip1) expression. E7C24G retained E7-wild-type capability to inhibit Miz-1-dependent transactivation. These findings suggest that HPV-16 E7 can repress Miz-1-induced p21(Cip1) gene expression. PMID:22099967

Morandell, Dieter; Kaiser, Andreas; Herold, Steffi; Rostek, Ursula; Lechner, Stefan; Mitterberger, Maria C; Jansen-Dürr, Pidder; Eilers, Martin; Zwerschke, Werner

2011-11-17

30

Correlation between serological immune response analyzed by a new ELISA for HPV16\\/18 E7 oncoprotein and clinical characteristics of cervical cancer patients  

Microsoft Academic Search

Summary.  Human papillomaviruses (HPVs), particularly HPV-16\\/18, are linked to cervical cancer development. Full-length, recombinant\\u000a HPV-16\\/18 E7 oncoproteins were used in a new streptavidin-biotin capture ELISA method to investigate anti-HPV E7 antibody\\u000a prevalence in serum. Sera from 99 healthy women, 70 cervical cancer patients, and 30 patients with cervical pre-invasive neoplasia\\u000a were analyzed. Anti-HPV-16\\/18 E7 positivity was found in 53% of cervical

A. Ravaggi; C. Romani; B. Pasinetti; R. A. Tassi; E. Bignotti; E. Bandiera; F. E. Odicino; M. Ragnoli; C. Donzelli; M. Falchetti; S. Calza; A. D. Santin; S. Pecorelli

2006-01-01

31

Human papillomavirus type 16 E7 oncoprotein inhibits the anaphase promoting complex/cyclosome activity by dysregulating EMI1 expression in mitosis.  

PubMed

The anaphase promoting complex/cyclosome (APC/C) is a ubiquitin ligase complex that orchestrates mitotic progression by targeting key mitotic regulators for proteasomal degradation. APC/C dysfunction is a frequent event during cancer development and can give rise to genomic instability. Here we report that the HPV16 E7 oncoprotein interferes with the degradation of APC/C substrates and that the APC/C inhibitor, EMI1, is expressed at higher levels in HPV16 E7-expressing mitotic cells. HPV16 E7 expression causes increased EMI1 mRNA expression and also inhibits EMI1 degradation. The resulting abnormally high EMI1 levels in HPV16 E7-expressing mitotic cells may inhibit degradation of APC/C substrates and cause the prometaphase delay that we have previously observed in such cells. PMID:24074588

Yu, Yueyang; Munger, Karl

2013-09-05

32

Locking Src/Abl Tyrosine Kinase Activities Regulate Cell Differentiation and Invasion of Human Cervical Cancer Cells Expressing E6/E7 Oncoproteins of High-Risk HPV  

PubMed Central

In this study, we compared the effects of SKI-606 with Iressa, Src/Abl and EGF-R kinase inhibitors, respectively, on selected parameters in HeLa and SiHa cervical cancer cell lines, which express E6/E7 oncoproteins of high-risk HPV types 18 and 16, respectively. Our results show that SKI-606 and Iressa inhibit cell proliferation and provoke G0-G1 cell cycle arrest and reduction of S and G2-M phase using 2 and 5??M concentrations of these inhibitors. In contrast, SKI-606 induces differentiation to an epithelial phenotype “mesenchymal-epithelial transition”; thus SKI-606 causes a dramatic decrease in cell motility and invasion abilities of HeLa and SiHa cancer cells, in comparison to untreated cells and Iressa-treated cells in which these parameters are only slightly affected. These changes are accompanied by a regulation of the expression patterns of E-cadherin and catenins. The molecular pathway analysis of Src/Abl inhibitor revealed that SKI-606 blocks the phosphorylation of ?-catenin and consequently converts its role from a transcriptional regulator to a cell-cell adhesion molecule. Our findings indicate that SKI-606 inhibits signaling pathways involved in regulating tumor cell migration and invasion genes via ?-catenin alteration, suggesting that Src inhibitor, in comparison to EGF-R, is a promising therapeutic agent for human cervical cancer.

Yasmeen, Amber; Alachkar, Amal; Dekhil, Hafedh; Gambacorti-Passerini, Carlo; Al Moustafa, Ala-Eddin

2010-01-01

33

Immunization with Human Papillomavirus Type 16 (HPV16) Oncoprotein-loaded Dendritic Cells as well as Protein in Adjuvant Induces MHC Class I-restricted Protection to HPV16-induced Tumor Cells1  

Microsoft Academic Search

Human papillomavirus (HPV) E6 and E7 oncoproteins are attractive targets for T-cell-based immunotherapy of cervical cancer. In this study, we demonstrate that dendritic cells (DCs) pulsed with HPV 16 E7 protein are not only recognized in vitro by E7-specific CTLs but also elicit E7- specific CTL responses in vivo, associated with protection against a chal lenge with syngeneic HPV16-induced tumor

Marloes L. H. De Bruijn; Danita H. Schuurhuis; Michel P. M. Vierboom; Hans Vermeulen; Karin A. J. de Cock; Marlies E. Ooms; Maaike E. Ressing; Mireille Toebes; Kees L. M. C. Franken; Jan-Wouter Drijfhout; Tom H. M. Ottenhoff; Rienk Offringa; Cornelis J. M. Melief

34

Expression of platelet-derived growth factor-beta receptor and bovine papillomavirus E5 and E7 oncoproteins in equine sarcoid.  

PubMed

Equine sarcoids are benign fibroblastic skin tumours that are recognized throughout the world. Infection with bovine papillomavirus (BPV) types 1 and 2 has been implicated as a major factor in disease development; however, the cellular mechanisms underlying fibroblast transformation remain poorly defined. The present study further characterizes aspects of the association with BPV in 15 equine sarcoids. BPV DNA was demonstrated in 12/15 tumours collected from different areas of Italy. Nine of these 12 tumours expressed the BPV oncoproteins E5 and E7, but these oncoproteins were not expressed by normal equine cells. The BPV E5 protein is known to bind to the platelet-derived growth factor-beta receptor (PDGF-betaR) and this molecule was expressed by 11 of the 12 sarcoids in which E5 was demonstrated. These findings add further weight to the theory that BPV and the PDGF-betaR may have a role in the pathogenesis of this disease. PMID:18814884

Borzacchiello, G; Russo, V; Della Salda, L; Roperto, S; Roperto, F

2008-09-23

35

Effects of the human papilloma virus HPV-16 E7 oncoprotein on glycolysis and glutaminolysis: role of pyruvate kinase type M2 and the glycolytic-enzyme complex.  

PubMed Central

Proliferating and tumour cells express the glycolytic isoenzyme, pyruvate kinase type M2 (M2-PK), which occurs in a highly active tetrameric form and in a dimeric form with low affinity for phosphoenolpyruvate. The switch between the two forms regulates glycolytic phosphometabolite pools and the interaction between glycolysis and glutaminolysis. In the present study, we show the effects of oncoprotein E7 of the human papilloma virus (HPV)-16 (E7)-transformation on two NIH 3T3 cell strains with different metabolic characteristics. E7-transformation of the high glycolytic NIH 3T3 cell strain led to a shift of M2-PK to the dimeric form and, in consequence, to a decrease in the cellular pyruvate kinase mass-action ratio, the glycolytic flux rate and the (ATP+GTP)/(UTP+CTP) ratio, as well as to an increase in fructose 1,6-bisphosphate (FBP) levels, glutamine consumption and cell proliferation. The low glycolytic NIH 3T3 cell strain is characterized by high pyruvate and glutamine consumption rates and by an intrinsically large amount of the dimeric form of M2-PK, which is correlated with high FBP levels, a low (ATP+GTP)/(CTP+UTP) ratio and a high proliferation rate. E7-transformation of this cell strain led to an alteration in the glycolytic-enzyme complex that correlates with an increase in pyruvate and glutamine consumption and a slight increase in the flow of glucose to lactate. The association of phosphoglyceromutase within the glycolytic-enzyme complex led to an increase of glucose and serine consumption and a disruption of the linkage between glucose consumption and glutaminolysis. In both NIH 3T3 cell lines, transformation increased glutaminolysis and the positive correlation between alanine and lactate production.

Mazurek, S; Zwerschke, W; Jansen-Durr, P; Eigenbrodt, E

2001-01-01

36

Chemo-radio Resistance in Cervical Cancer Induced by HPV16 E7  

Microsoft Academic Search

Alteration of the apoptosis pathway, as well as the presence of human papilloma virus (HPV), has been linked to the proliferative capacity and drug resistant phenotype of SiHa cervical cancer. We investigated the roles of E6 and E7 HPV oncoproteins in the expression of apoptosis regulating genes in cervical cancer cells that contain the characteristics of apoptosis resistance, and also

Saharat Aungsumart

37

Inhibition of Serum and Calcium-Induced Differentiation of Human Keratinocytes by HPV16 E6 Oncoprotein: Role of p53 Inactivation  

Microsoft Academic Search

We have recently shown that human papillomavirus (HPV16) E6 oncoprotein exhibits two separate biological activities in genital keratinocytes (PHKs). E6 protein by itself is capable of inducing colonies of proliferating cells resistant to serum and calcium-induced differentiation, whereas both E6 and E7 are required for immortalization of PHK. Using epitope-tagged E6 carboxy-terminal truncation mutants, we mapped the domain between amino

Levana Sherman; Anna Jackman; Hagar Itzhaki; Melissa Conrad Stöppler; Debbie Koval; Richard Schlegel

1997-01-01

38

Low-Dose Adenovirus Vaccine Encoding Chimeric Hepatitis B Virus Surface Antigen-Human Papillomavirus Type 16 E7 Proteins Induces Enhanced E7-Specific Antibody and Cytotoxic T-Cell Responses  

PubMed Central

Induction of effective immune responses may help prevent cancer progression. Tumor-specific antigens, such as those of human papillomaviruses involved in cervical cancer, are targets with limited intrinsic immunogenicity. Here we show that immunization with low doses (106 infectious units/dose) of a recombinant human adenovirus type 5 encoding a fusion of the E7 oncoprotein of human papillomavirus type 16 to the carboxyl terminus of the surface antigen of hepatitis B virus (HBsAg) induces remarkable E7-specific humoral and cellular immune responses. The HBsAg/E7 fusion protein assembled efficiently into virus-like particles, which stimulated antibody responses against both carrier and foreign antigens, and evoked antigen-specific kill of an indicator cell population in vivo. Antibody and T-cell responses were significantly higher than those induced by a control adenovirus vector expressing wild-type E7. Such responses were not affected by preexisting immunity against either HBsAg or adenovirus. These data demonstrate that the presence of E7 on HBsAg particles does not interfere with particle secretion, as it occurs with bigger proteins fused to the C terminus of HBsAg, and results in enhancement of CD8+-mediated T-cell responses to E7. Thus, fusion to HBsAg is a convenient strategy for developing cervical cancer therapeutic vaccines, since it enhances the immunogenicity of E7 while turning it into an innocuous secreted fusion protein.

Baez-Astua, Andres; Herraez-Hernandez, Elsa; Garbi, Natalio; Pasolli, Hilda A.; Juarez, Victoria; zur Hausen, Harald; Cid-Arregui, Angel

2005-01-01

39

Low-dose adenovirus vaccine encoding chimeric hepatitis B virus surface antigen-human papillomavirus type 16 E7 proteins induces enhanced E7-specific antibody and cytotoxic T-cell responses.  

PubMed

Induction of effective immune responses may help prevent cancer progression. Tumor-specific antigens, such as those of human papillomaviruses involved in cervical cancer, are targets with limited intrinsic immunogenicity. Here we show that immunization with low doses (10(6) infectious units/dose) of a recombinant human adenovirus type 5 encoding a fusion of the E7 oncoprotein of human papillomavirus type 16 to the carboxyl terminus of the surface antigen of hepatitis B virus (HBsAg) induces remarkable E7-specific humoral and cellular immune responses. The HBsAg/E7 fusion protein assembled efficiently into virus-like particles, which stimulated antibody responses against both carrier and foreign antigens, and evoked antigen-specific kill of an indicator cell population in vivo. Antibody and T-cell responses were significantly higher than those induced by a control adenovirus vector expressing wild-type E7. Such responses were not affected by preexisting immunity against either HBsAg or adenovirus. These data demonstrate that the presence of E7 on HBsAg particles does not interfere with particle secretion, as it occurs with bigger proteins fused to the C terminus of HBsAg, and results in enhancement of CD8(+)-mediated T-cell responses to E7. Thus, fusion to HBsAg is a convenient strategy for developing cervical cancer therapeutic vaccines, since it enhances the immunogenicity of E7 while turning it into an innocuous secreted fusion protein. PMID:16188983

Báez-Astúa, Andrés; Herráez-Hernández, Elsa; Garbi, Natalio; Pasolli, Hilda A; Juárez, Victoria; Zur Hausen, Harald; Cid-Arregui, Angel

2005-10-01

40

Recombinant Lipidated HPV E7 Induces a Th-1-Biased Immune Response and Protective Immunity against Cervical Cancer in a Mouse Model  

PubMed Central

The E7 oncoprotein of human papillomavirus (HPV) is an ideal target for developing immunotherapeutic strategies against HPV-associated tumors. However, because protein-based immunogens alone are poor elicitors of the cytotoxic T-lymphocyte (CTL) responses, they have been difficult to exploit for therapeutic purposes. In this study, we report that a recombinant lipoprotein consisting of inactive E7 (E7m) biologically linked to a bacterial lipid moiety (rlipo-E7m) induces the maturation of mouse bone marrow-derived dendritic cells through toll-like receptor 2 (TLR2), skews the immune responses toward the Th1 responses and induces E7-specific CTL responses. We further studied the ability of rlipo-E7m to provide protection against a TC-1 tumor cell challenge in an animal model. Mice prophylactically immunized with two 10-µg doses of rlipo-E7m were found to be free of TC-1 tumor growth. Experiments in a therapeutic immunization model showed that the tumor volume in mice receiving a single dose of rlipo-E7m was less than 0.01 cm3 on day 40, whereas the tumor volume in mice treated with rE7m was 2.28±1.21 cm3. The tumor volume of the entire control group was over 3 cm3. In addition, we demonstrated that the CD8+ T cells play a major role in anti-tumor immunity when administration of rlipo-E7m. These results demonstrate that rlipo-E7m could be a promising candidate for treating HPV-associated tumors.

Shen, Kuan-Yin; Chang, Li-Sheng; Yeh, Yi-Chen; Chen, I-Hua; Chong, Pele; Liu, Shih-Jen; Leng, Chih-Hsiang

2012-01-01

41

Accumulation of Human Papillomavirus Type 16 E7 Protein Bypasses G 1 Arrest Induced by Serum Deprivation and by the Cell Cycle Inhibitor p21  

Microsoft Academic Search

The E7 oncoproteins encoded by the high-risk type of human papillomaviruses (HPVs) interact with the Rb familyproteinsRb,p107,andp130.TheRbfamilyproteinsassociatewiththefactorsoftheE2Ffamilytoform transcription repressor complexes, which control expression of several genes essential for S-phase entry and DNA replication. The E7 oncoproteins, by interacting with the Rb family proteins, dissociate the repressor complexes involving the factors of the E2F and Rb families, leading to a release

ALEXEI MOROZOV; PAVEL SHIYANOV; ELIAV BARR; JEFFREY M. LEIDEN; ANDPRADIP RAYCHAUDHURI

1997-01-01

42

Initiation of DNA synthesis by human papillomavirus E7 oncoproteins is resistant to p21-mediated inhibition of cyclin E-cdk2 activity.  

PubMed Central

The E6 and E7 proteins from the high-risk human papillomaviruses (HPVs) bind and inactivate the tumor suppressor proteins p53 and Rb, respectively. In HPV-positive cells, expression of E6 proteins from high-risk types results in increased turnover of p53, which leads to an abrogation of p21-mediated G1/S arrest in response to DNA-damaging agents. In contrast, keratinocytes which express E7 alone have increased levels of p53 but, interestingly, also fail to undergo a G1/S arrest. We investigated the mechanism by which E7 bypasses this p21 arrest by using both keratinocytes which stably express E7 as well as U20S cells which stably or transiently express E7. We observed that E7 does not affect the induction of p21 synthesis by p53. While glutathione S-transferase (GST)-E7 bound a low level of in vitro-translated p21, we were unable to detect E7 and p21 in the same complex by GST-E7 binding assays or immunoprecipitations from cell extracts. Furthermore, E7 did not prevent p21-mediated inhibition of cyclin E kinase activity. In keratinocytes expressing E7, increased levels of p53, p21, and cyclin E, as well as increased cyclin E kinase activity, were observed. To determine if this increase in cyclin E activity was necessary for E7's ability to overcome p21-mediated G1/S arrest, we examined U20S cells in which cyclin E levels are not increased in response to E7 expression. U20S cells which stably express E7 were found to initiate DNA synthesis in the presence of DNA-damaging agents despite the inhibition of cyclin E activity by p21. In transient assays, cotransfection of E7 or E2F-1 along with p21 into U20S cells rescued G1 arrest and resulted in S-phase entry, as measured by the ability to incorporate bromodeoxyuridine. These data indicate that E7 is able to overcome G1/S arrest without directly affecting p21 function and likely acts through deregulation of E2F activity.

Ruesch, M N; Laimins, L A

1997-01-01

43

Nuclear import of high risk HPV16 E7 oncoprotein is mediated by its zinc-binding domain via hydrophobic interactions with Nup62.  

PubMed

We previously discovered that nuclear import of high risk HPV16 E7 is mediated by a cNLS located within the zinc-binding domain via a pathway that is independent of karyopherins/importins (Angeline et al., 2003; Knapp et al., 2009). In this study we continued our characterization of the cNLS and nuclear import pathway of HPV16 E7. We find that an intact zinc-binding domain is essential for the cNLS function in mediating nuclear import of HPV16 E7. Mutagenesis of cysteine residues to alanine in each of the two CysXXCys motifs involved in zinc-binding changes the nuclear localization of the EGFP-16E7 and 2xEGFP-16E7 mutants. We further discover that a patch of hydrophobic residues, 65LRLCV69, within the zinc-binding domain of HPV16 E7 mediates its nuclear import via hydrophobic interactions with the FG domain of the central channel nucleoporin Nup62. PMID:24074597

Eberhard, Jeremy; Onder, Zeynep; Moroianu, Junona

2013-09-10

44

Purified herpes simplex type 1 glycoprotein D (gD) genetically fused with the type 16 human papillomavirus E7 oncoprotein enhances antigen-specific CD8+ T cell responses and confers protective antitumor immunity.  

PubMed

Type 1 herpes virus (HSV-1) glycoprotein D (gD) enhances antigen-specific immune responses, particularly CD8(+) T cell responses, in mice immunized with DNA vaccines encoding hybrid proteins genetically fused with the target antigen at a site near the C-terminal end. These effects are attributed to the interaction of gD with the herpes virus entry mediator (HVEM) and the concomitant blockade of a coinhibitory mechanism mediated by the B- and T-lymphocyte attenuator (BTLA). However, questions concerning the requirement for endogenous synthesis of the antigen or the adjuvant/antigen fusion itself have not been addressed so far. In the present study, we investigated these points using purified recombinant gDs, genetically fused or not with type 16 papilloma virus (HPV-16) E7 oncoprotein. Soluble recombinant gDs, but not denatured forms, retained the ability to bind surface-exposed cellular receptors of HVEM-expressing U937 cells. In addition, in vivo administration of the recombinant proteins, particularly gD genetically fused with E7 (gDE7), promoted the activation of dendritic cells (DC) and antigen-specific cytotoxic CD8(+) T cells. More relevantly, mice immunized with the gDE7 protein developed complete preventive and partial therapeutic antitumor protection, as measured in mice following the implantation of TC-1 cells expressing HPV-16 oncoproteins. Collectively, these results demonstrate that the T cell adjuvant effects of the HSV-1 gD protein did not require endogenous synthesis and could be demonstrated in mice immunized with purified recombinant proteins. PMID:21985578

Porchia, Bruna F M M; Diniz, Mariana O; Cariri, Francisco A M O; Santana, Vinícius C; Amorim, Jaime H; Balan, Andrea; Braga, Catarina J M; Ferreira, Luís Carlos S

2011-10-19

45

High levels of p105 (NFKB1) and p100 (NFKB2) proteins in HPV16-transformed keratinocytes: role of E6 and E7 oncoproteins  

SciTech Connect

We have previously shown that functional components of the NF-{kappa}B signaling pathway are up-regulated and sequestered in the cytoplasm of human papillomavirus 16 (HPV16)-transformed cell lines leading to a reduced activity of NF-{kappa}B. In this study, we examined the expression of the NF-{kappa}B precursors p100 and p105 in keratinocytes transformed or not by HPV16. Western immunoblotting experiments demonstrated high levels of p100 and p105 proteins not only in HPV16{sup +} cervical carcinoma-derived keratinocytes but also in keratinocytes stably transfected by HPV16 E6 or E7 oncogenes. Moreover, p100 and p105 proteins were predominantly cytoplasmic and nuclear in keratinocytes expressing E7 and E6, respectively. A predominantly cytoplasmic localization of E7 protein was also detected in all keratinocytes expressing E7. Our results suggest that HPV16 E6 and E7 proteins modulate the expression and the subcellular localization of p100 and p105 NF-{kappa}B precursors.

Havard, L. [University Hospital of Liege, Department of Pathology, Tour de Pathologie, B23, 4000 Liege (Belgium); Rahmouni, S. [University Hospital of Liege, Department of Pathology, Tour de Pathologie, B23, 4000 Liege (Belgium); Boniver, J. [University Hospital of Liege, Department of Pathology, Tour de Pathologie, B23, 4000 Liege (Belgium); Delvenne, P. [University Hospital of Liege, Department of Pathology, Tour de Pathologie, B23, 4000 Liege (Belgium)]. E-mail: P.Delvenne@ulg.ac.be

2005-01-20

46

Functional Interaction between Human Papillomavirus Type 16 E6 and E7 Oncoproteins and Cigarette Smoke Components in Lung Epithelial Cells  

Microsoft Academic Search

The smoking habit is the most important, but not a sufficient cause for lung cancer development. Several studies have reported the human papillomavirus type 16 (HPV16) presence and E6 and E7 transcripts expression in lung carcinoma cases from different geographical regions. The possible interaction between HPV infection and smoke carcinogens, however, remains unclear. In this study we address a potential

Juan Pablo Muñoz; Carolina González; Bárbara Parra; Alejandro H. Corvalán; Maria Lina Tornesello; Yoshito Eizuru; Francisco Aguayo

2012-01-01

47

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

PubMed

Human papilloma virus type 16 (HPV16) E7 is a viral oncoprotein that is believed to play a major role in cervical neoplasia. A novel antagonist peptide against HPV16 E7 was previously selected by phage display screening and the selected peptide was found to have anti-tumor efficacy against HPV16-positive cervical carcinoma through induction of cell cycle arrest. In the current study, to further elucidate the mechanisms of the antagonist peptide, the effects of the peptide on apoptosis are investigated by RT-PCR, Western blotting, MTT assay, TUNEL staining, Annexin V apoptosis assay, flow cytometry, and animal experiments. The antagonist peptide showed obvious anti-tumor efficacy through apoptosis induction, both in HPV16-positive cervical cancer cell lines and tumor xenografts. Our results also revealed that the peptide induced accumulation of cellular p53 and p21, and led to HPV16 E7 protein degradation. In the case of mRNA levels, it resulted in unaltered p53 and HPV16 E7 expression, but increased expression of p21. In contrast, the induction of apoptosis and p53 reactivation effects by the selected peptide were abolished after E7 knocked down with siRNA. These results demonstrate that the selected peptide can induce E7 degradation and lead to marked apoptosis in HPV16-related cancer cells by activating cellular p53 and its target genes, such as p21. Furthermore, the evident therapeutic efficacy obtained from the subcutaneous tumor model experiments in nude mice suggests a therapeutic potential for HPV16-related cancers of the selected peptide. Therefore, this specific peptide may be used to create specific biotherapies for the treatment of HPV 16-positive cervical cancers. PMID:21475994

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

2011-06-01

48

Human Papillomavirus E7 Induces Rereplication in Response to DNA Damage  

PubMed Central

Human papillomavirus (HPV) infection is necessary but not sufficient for cervical carcinogenesis. Genomic instability caused by HPV allows cells to acquire additional mutations required for malignant transformation. Genomic instability in the form of polyploidy has been demonstrated to play an important role in cervical carcinogenesis. We have recently found that HPV-16 E7 oncogene induces polyploidy in response to DNA damage; however, the mechanism is not known. Here we present evidence demonstrating that HPV-16 E7-expressing cells have an intact G2 checkpoint. Upon DNA damage, HPV-16 E7-expressing cells arrest at the G2 checkpoint and then undergo rereplication, a process of successive rounds of host DNA replication without entering mitosis. Interestingly, the DNA replication initiation factor Cdt1, whose uncontrolled expression induces rereplication in human cancer cells, is upregulated in E7-expressing cells. Moreover, downregulation of Cdt1 impairs the ability of E7 to induce rereplication. These results demonstrate an important role for Cdt1 in HPV E7-induced rereplication and shed light on mechanisms by which HPV induces genomic instability.

Fan, Xueli; Liu, Yingwang; Heilman, Susan A.

2013-01-01

49

miR-1226 targets expression of the mucin 1 oncoprotein and induces cell death  

PubMed Central

The MUC1 oncoprotein is aberrantly overexpressed in human carcinomas and hematologic malignancies. MicroRNAs (miRNAs) have been implicated in the suppression and induction of oncogenesis. The present studies demonstrate that the MUC1 mRNA 3? untranslated region (3?UTR) contains a highly conserved motif for binding of a novel miRNA, miR-1226, that has no known targets. The results show that miR-1226 is expressed in human breast cancer cell lines and non-malignant mammary epithelial cells. We also show that miR-1226 interacts with the MUC1 mRNA 3?UTR and that miR-1226 downregulates endogenous MUC1 protein levels. Consistent with miR-1226-induced downregulation of MUC1 expression, the results demonstrate that miR-1226 induces (i) an increase in reactive oxygen species, (ii) loss of the mitochondrial transmembrane potential, and (iii) a decrease in cell survival. These findings indicate that expression of the MUC1 oncoprotein is downregulated by miR-1226 and that miR-1226 thereby functions as a tumor suppressor by promoting the induction of cell death.

JIN, CAINING; RAJABI, HASAN; KUFE, DONALD

2011-01-01

50

E6/E7 proteins of HPV type 16 and ErbB-2 cooperate to induce neoplastic transformation of primary normal oral epithelial cells.  

PubMed

Head and neck squamous cell carcinomas (HNSCC) are characterized by a marked propensity for local invasion and spread to cervical lymph nodes, with distant metastases developing in 30-40% of cases. HPV-16 is an important risk factor for HNSCC. How HPV enhances susceptibility to HNSCC is not fully understood, but seems to involve cofactors. In this study, we examined the effect of the cooperation between HPV-16 and the tyrosine kinase receptor ErbB-2 on E-cadherin/catenin complex patterns and neoplastic transformation of human normal oral epithelial (NOE) cells. We report that overexpression of ErbB-2 or E6/E7 alone does not affect E-cadherin/catenin complex patterns nor does it induce cell transformation of NOE cells. In contrast, coexpression of E6/E7 and ErbB-2 downregulates E-cadherin and catenin expression. This is accompanied by cytoplasmic localization of E-cadherin, as well as nuclear translocation of alpha, beta, and gamma-catenins. Furthermore, we demonstrate that E6/E7 cooperate with overexpressed ErbB-2 to induce tumor formation in nude mice and to upregulate cyclin D1 and c-myc expression. Our data suggest that E6/E7 cooperate with ErbB-2 in head and neck carcinogenesis, at least in part, via the conversion of beta-catenin from a cell adhesion to a nuclear function, that is, to act as a potential transcriptional regulator. This conversion leads to the upregulation of cyclin D1, c-myc and other oncoproteins necessary for alteration of the E-cadherin/catenin complex and cell transformation of NOE cells. PMID:14724563

Al Moustafa, Ala-Eddin; Foulkes, William D; Benlimame, Naciba; Wong, Annick; Yen, Lily; Bergeron, Josée; Batist, Gerald; Alpert, Lesley; Alaoui-Jamali, Moulay A

2004-01-15

51

Cyclin D1 is essential for neoplastic transformation induced by both E6\\/E7 and E6\\/E7\\/ErbB-2 cooperation in normal cells  

Microsoft Academic Search

More than 25% of head and neck squamous cell carcinomas (HNSCC) and 99% of cervical cancers (CxCa) are positive for high-risk human papillomaviruses (HPVs). Furthermore, the type I tyrosine kinase receptor ErbB-2 is overexpressed in at least 30% of HNSCC and CxCa. Recently, we demonstrated that E6\\/E7 of HPV type 16 cooperate with ErbB-2 to induce cell transformation of human

Ala-Eddin Al Moustafa; William D Foulkes; Annick Wong; Houda Jallal; Gerald Batist; Qunyan Yu; Meenhard Herlyn; Piotr Sicinski; Moulay A Alaoui-Jamali; A-E Al Moustafa

2004-01-01

52

p53 oncoprotein overexpression correlates with mutagen-induced chromosome fragility in head and neck cancer patients with multiple malignancies  

Microsoft Academic Search

In this study, we analysed immunocytochemically p53 expression in first primary and second primary cancers from 25 head and neck cancer patients (HNCPs) with multiple malignancies in comparison with oncoprotein expression in tumour tissues from 25 historical HNCP controls with single cancer in a match-paired analysis. Moreover, we investigated bleomycin-induced chromosome fragility in both groups of HNCPs and in 21

O Gallo; S Bianchi; ML Giovannucci-Uzzielli; R Santoro; S Lenzi; C Salimbeni; M Abbruzzese; E Alajmo

1995-01-01

53

Overload-induced C-Myc oncoprotein is reduced in aged skeletal muscle.  

PubMed

The C-Myc oncoprotein was examined in anterior latissimus dorsi (ALD) muscles of young (6 weeks) and aged (90 weeks) quail after 0.5 hours to 14 days of stretch. Western analyses of nuclear extracts showed an increase in the C-Myc oncoprotein after 1 h of stretch in young adult birds, and C-Myc remained elevated for 3 days of stretch. The onset and total accumulation of the C-Myc oncoprotein was less in muscles from aged quail as compared to muscles from young adult birds. Immunocytochemical analyses showed that C-Myc was localized in nuclei and averaged 0.2 +/- 0.04 nuclei/muscles fiber cross-section (n/f) in control muscles. C-Myc immunopositive nuclei were more numerous in muscles from young adult birds (1.7 +/- 0.2 n/f) compared to aged birds (1.1 +/- 0.1 n/f) after 2-12 h of stretch. C-Myc positive nuclei declined to 0.7 +/- 0.1 n/f after 3 days of stretch, in muscles from young adult birds; however, this was greater than in muscles from aged birds at the same time point (0.3 +/- 0.04 n/f). Many nuclei that were associated with muscle fibers expressed the C-Myc oncoprotein but did not incorporate bromodeoxyuridine, a marker of DNA synthesis and activated satellite cells. These data show a decreased ability of skeletal muscles from aged quails to initiate a program inclusive of early C-Myc oncoprotein accumulation in response to stretch. PMID:9224425

Alway, S E

1997-07-01

54

Antisense targeting human papillomavirus type 16 E6 and E7 genes contributes to apoptosis and senescence in SiHa cervical carcinoma cells  

Microsoft Academic Search

ObjectiveHuman papillomavirus type 16 (HPV-16) is a high-risk DNA tumor virus involved in the development of cervical carcinomas. Substantial studies have demonstrated that E6 and E7 oncoproteins of HPV-16 could induce cell proliferation and immortalization. Repression of E6 and\\/or E7 oncogenes may induce cervical cancer cells to undergo apoptosis or senescence. The purpose of this study was to determine whether

Ni Sima; Shixuan Wang; Wei Wang; Debo Kong; Qian Xu; Xu Tian; Aiyue Luo; Jianfeng Zhou; Gang Xu; Li Meng; Yunping Lu; Ding Ma

2007-01-01

55

Human hsp70 and HPV16 oE7 fusion protein vaccine induces an effective antitumor efficacy.  

PubMed

The persistent infection by human papilloma virus (HPV) is considered to be the major risk factor of cervical cancer, which is one of the most common cancers in women worldwide. Millions of women are currently infected with high-risk HPV. Thus, it is urgent to develop therapeutic vaccines to eliminate established infection or HPV-related diseases. In the present study, we constructed a very promising therapeutic HPV16 protein vaccine of optimized E7 (oE7)/huhsp70 using human hsp70 linked to HPV16 oE7. Our results demonstrated that vaccination with the oE7/huhsp70 protein vaccine induced a very strong E7-specific CD8(+) T cell immune response and resulted in a significant therapeutic effect against E7-expressing tumor cells. Our study verifies that huhsp70 is an effective immune adjuvant in the development of tumor therapeutic protein vaccines, and emphasizes that homologous huhsp70 is a promising tool in future human clinical applications. PMID:23660931

Zong, Jinbao; Wang, Changyuan; Liu, Bin; Liu, Mingjun; Cao, Yongxian; Sun, Xiufang; Yao, Yuan; Sun, Guirong

2013-05-09

56

Anti-cancer activity of plant-produced HPV16 E7 vaccine.  

PubMed

The E7 oncoprotein from Human Papilloma Virus (HPV) is an attractive candidate for anti-cancer vaccine development. In this study, we engineered HPV16 E7 coding sequence (wild type or mutagenized sequence, E7GGG) as fusions to beta-1,3-1,4-glucanase (LicKM) of Clostridium thermocellum and produced in Nicotiana benthamiana plants using a transient expression system. Target antigens were purified and evaluated in mice for their potential as prophylactic and therapeutic vaccine candidates. Both fusion proteins induced E7-specific IgG and cytotoxic T-cell responses and protected mice against challenge with E7-expressing tumor cells. Furthermore, when administered after challenge, these plant-produced antigens prevented tumor development. PMID:17280752

Massa, Silvia; Franconi, Rosella; Brandi, Rossella; Muller, Antonio; Mett, Vadim; Yusibov, Vidadi; Venuti, Aldo

2007-01-19

57

Protection against human papillomavirus type 16-induced tumors in mice using non-genetically modified lactic acid bacteria displaying E7 antigen at its surface.  

PubMed

Human papillomavirus (HPV) is the causative agent of cervical cancer (CxCa) and the most commonly sexually transmitted pathogen worldwide. HPV type 16 (HPV-16) E7 oncoprotein is constitutively produced in CxCa and considered as a good antigen candidate for the development of new therapeutic CxCa vaccines. Here, we report the use of non-genetically modified, E7-expressing lactic acid bacteria (LAB) by using the cell-binding domain from Lactobacillus casei A2 phage lysin as a cell wall anchor. The versatility of this system was validated by investigating E7 stability at the surface of Lactococcus lactis and L. casei, two major species of LAB. Moreover, we demonstrated the successful use of these LAB displaying E7 antigen as a mucosal live vaccine in mice. Altogether, these results show the feasibility of using non-genetically modified LAB for low-cost mucosal immunotherapy against HPV-related CxCa in humans. PMID:23212671

Ribelles, Pedro; Benbouziane, Bouasria; Langella, Philippe; Suárez, Juan E; Bermúdez-Humarán, Luis G

2012-12-05

58

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

59

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

PubMed

Human papilloma virus (HPV) 16 causes cervical cancer. Induction of oncogenesis by HPV 16 is primarily dependent on the function of E6 and E7 proteins, which inactivate the function of p53 and pRB, respectively. Thus, blocking the activity of the E6 and E7 proteins from HPV 16 is critical to inhibiting oncogenesis during infection. We have expressed and purified soluble HPV 16 E6 and E7 fusion immunoglobulin (Ig), which were combined with the constant region of an Ig heavy chain, in a mammalian system. To assess whether soluble E6 and E7 fusion Igs induce effective cellular immune responses, immature dendritic cells (DCs) were treated with these fusion proteins. Soluble E6 and E7 fusion Igs effectively induced maturation of DCs. Furthermore, immunization with soluble E6 and E7 fusion Igs in mice resulted in antigen-specific activation of T helper 1 (Th1) cells. This is the first comprehensive study to show the molecular basis of how soluble HPV 16 E6 or E7 fusion Igs induces Th1 responses through the maturation of DCs. In addition, we show that DC therapy using soluble HPV E6 and E7 fusion Igs may be a valuable tool for controlling the progress of cervical cancer. PMID:21140193

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

2010-12-08

60

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

61

Viral oncoproteins target the DNA methyltransferases  

Microsoft Academic Search

Small DNA tumour viruses have evolved a number of mechanisms to drive nondividing cells into S phase. Virally encoded oncoproteins such as adenovirus E1A and human papillomavirus (HPV) E7 can bind an array of cellular proteins to override proliferation arrest. The DNA methyltransferase Dnmt1 is the major mammalian enzyme responsible for maintaining CpG methylation patterns in the cell following replication.

W A Burgers; L Blanchon; S Pradhan; Y de Launoit; T Kouzarides; F Fuks

2007-01-01

62

Expression of LIGHT/TNFSF14 combined with vaccination against human papillomavirus Type 16 E7 induces significant tumor regression.  

PubMed

LIGHT, a ligand for the lymphotoxin-beta receptor, establishes lymphoid-like tissues inside tumor sites and recruits naïve T cells into the tumor. However, whether these infiltrating T cells are specific for tumor antigens is not known. We hypothesized that therapy with LIGHT can expand functional tumor-specific CD8(+) T cells that can be boosted using HPV16E6E7-Venezuelan equine encephalitis virus replicon particles (HPV16-VRP) and that this combined therapy can eradicate human papillomavirus 16 (HPV16)-induced tumors. Our data show that forced expression of LIGHT in tumors results in an increase in expression of IFNgamma and chemoattractant cytokines such as interleukin-1a, MIG, and macrophage inflammatory protein-2 within the tumor and that this tumor microenvironment correlates with an increase in frequency of tumor-infiltrating CD8(+) T cells. Forced expression of LIGHT also results in the expansion of functional T cells that recognize multiple tumor antigens, including HPV16 E7, and these T cells prevent the outgrowth of tumors on secondary challenge. Subsequent boosting of E7-specific T cells by vaccination with HPV16-VRP significantly increases their frequency in both the periphery and the tumor and leads to the eradication of large well-established tumors, for which either treatment alone is not successful. These data establish the safety of Ad-LIGHT as a therapeutic intervention in preclinical studies and suggest that patients with HPV16(+) tumors may benefit from combined immunotherapy with LIGHT and antigen-specific vaccination. PMID:20460520

Kanodia, Shreya; Da Silva, Diane M; Karamanukyan, Tigran; Bogaert, Lies; Fu, Yang-Xin; Kast, W Martin

2010-05-11

63

The Agrobacterium vitis T-6b oncoprotein induces auxin-independent cell expansion in tobacco.  

PubMed

Among the Agrobacterium T-DNA genes, rolB, rolC, orf13, orf8, lso, 6b and several other genes encode weakly homologous proteins with remarkable effects on plant growth. The 6b oncogene induces tumors and enations. In order to study its properties we have used transgenic tobacco plants that carry a dexamethasone-inducible 6b gene, dex-T-6b. Upon induction, dex-T-6b plants develop a large array of morphological modifications, some of which involve abnormal cell expansion. In the present investigation, dex-T-6b-induced expansion was studied in intact leaves and an in vitro leaf disc system. Although T-6b and indole-3-acetic acid (IAA) both induced expansion and were non-additive, T-6b expression did not increase IAA levels, nor did it induce an IAA-responsive gene. Fusicoccin (FC) is known to stimulate expansion by increasing cell wall plasticity. T-6b- and FC-induced expansion were additive at saturating FC concentrations, indicating that T-6b does not act by a similar mechanism to FC. T-6b expression led to higher leaf osmolality values, in contrast to FC, suggesting that the T-6b gene induces expansion by increasing osmolyte concentrations. Metabolite profiling showed that glucose and fructose played a major role in this increase. We infer that T-6b disrupts the osmoregulatory controls that govern cell expansion during development and wound healing. PMID:16507091

Clément, Bernadette; Pollmann, Stephan; Weiler, Elmar; Urbanczyk-Wochniak, Ewa; Otten, Léon

2006-03-01

64

Analysis of the conformational change of recombinant human papilloma virus type 18 E7 protein induced by metal binding  

Microsoft Academic Search

Human papillomavirus (HPV) type 18 E7 gene was isolated by polymerase chain reaction (PCR) amplification from tissues of Korean cervical cancer patients and cloned into a plasmid vector, pET-3a, for the expression of recombinant E7 protein (rE7) in Escherichiacoli. The rE7 protein was purified to the homogeneity and its purity was confirmed by HPLC. The purified protein was analyzed for

Joo Hyun Kang; Seung Won Jin; Hee Shick Yoon; Wang Don Yoo; Hyun Su Kim; Kyung-Soo Hahm; Sue Nie Park

1997-01-01

65

Involvement of aryl hydrocarbon receptor signaling in the development of small cell lung cancer induced by HPV E6\\/E7 oncoproteins  

Microsoft Academic Search

BACKGROUND: Lung cancers consist of four major types that and for clinical-pathological reasons are often divided into two broad categories: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). All major histological types of lung cancer are associated with smoking, although the association is stronger for SCLC and squamous cell carcinoma than adenocarcinoma. To date, epidemiological studies have

Tonia Buonomo; Laura Carraresi; Mara Rossini; Rosanna Martinelli

2011-01-01

66

Cutaneous Human Papillomavirus Type 38 E7 Regulates Actin Cytoskeleton Structure for Increasing Cell Proliferation through CK2 and the Eukaryotic Elongation Factor 1A?†  

PubMed Central

We previously reported that the oncoproteins E6 and E7 from cutaneous human papillomavirus type 38 (HPV38) can immortalize primary human keratinocytes in vitro and sensitize transgenic mice to develop skin cancer in vivo. Immunofluorescence staining revealed that human keratinocytes immortalized by HPV38 E6 and E7 display fewer actin stress fibers than do control primary keratinocyte cells, raising the possibility of a role of the viral oncoproteins in the remodeling of the actin cytoskeleton. In this study, we show that HPV38 E7 induces actin stress fiber disruption and that this phenomenon correlates with its ability to downregulate Rho activity. The downregulation of Rho activity by HPV38 E7 is mediated through the activation of the CK2–MEK–extracellular signal-regulated kinase (ERK) pathway. In addition, HPV38 E7 is able to induce actin fiber disruption by binding directly to eukaryotic elongation factor 1A (eEF1A) and abolishing its effects on actin fiber formation. Finally, we found that the downregulation of Rho activity by HPV38 E7 through the CK2-MEK-ERK pathway facilitates cell growth proliferation. Taken together, our data support the conclusion that HPV38 E7 promotes keratinocyte proliferation in part by negatively regulating actin cytoskeleton fiber formation through the CK2-MEK-ERK-Rho pathway and by binding to eEF1A and inhibiting its effects on actin cytoskeleton remodeling.

Yue, Jiping; Shukla, Ruchi; Accardi, Rosita; Zanella-Cleon, Isabelle; Siouda, Maha; Cros, Marie-Pierre; Krutovskikh, Vladimir; Hussain, Ishraq; Niu, Yamei; Hu, Shiqiong; Becchi, Michel; Jurdic, Pierre; Tommasino, Massimo; Sylla, Bakary S.

2011-01-01

67

A non-oncogenic HPV 16 E6/E7 vaccine enhances treatment of HPV expressing tumors.  

PubMed

Human papillomaviruses (HPVs) are the causative factor for >90% of cervical cancers and 25% of head and neck cancers. The incidence of HPV positive (+) head and neck squamous cell carcinomas 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 pre-clinical 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, B G; Vermeer, D W; Spanos, W C; Lee, K M; Vermeer, P; Lee, W T; Xu, Y; Gabitzsch, E S; Balcaitis, S; Balint, J P; Jones, F R; Lee, J H

2012-08-24

68

Splicing-factor oncoprotein SRSF1 stabilizes p53 via RPL5 and induces cellular senescence.  

PubMed

Splicing and translation are highly regulated steps of gene expression. Altered expression of proteins involved in these processes can be deleterious. Therefore, the cell has many safeguards against such misregulation. We report that the oncogenic splicing factor SRSF1, which is overexpressed in many cancers, stabilizes the tumor suppressor protein p53 by abrogating its MDM2-dependent proteasomal degradation. We show that SRSF1 is a necessary component of an MDM2/ribosomal protein complex, separate from the ribosome, that functions in a p53-dependent ribosomal-stress checkpoint pathway. Consistent with the stabilization of p53, increased SRSF1 expression in primary human fibroblasts decreases cellular proliferation and ultimately triggers oncogene-induced senescence (OIS). These findings underscore the deleterious outcome of SRSF1 overexpression and identify a cellular defense mechanism against its aberrant function. Furthermore, they implicate the RPL5-MDM2 complex in OIS and demonstrate a link between spliceosomal and ribosomal components, functioning independently of their canonical roles, to monitor cellular physiology and cell-cycle progression. PMID:23478443

Fregoso, Oliver I; Das, Shipra; Akerman, Martin; Krainer, Adrian R

2013-03-07

69

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

2013-04-27

70

The expression of human papillomavirus type 16 (HPV16 E7) induces cell cycle arrest and apoptosis in radiation and hypoxia resistant glioblastoma cells.  

PubMed

p53 is a widely known tumor-suppressor gene product that plays a key role in apoptotic cell death induced by DNA-damaging chemotherapeutic agents. Human glioma cells with functional p53 are known to be more resistant to ?-radiation. The aim of this study was to investigate whether the mutant glioblastoma cells (U87MG) transfected with human papilloma virus-type 16 E7 (HPV16 E7) genes were capable of increasing sensitivity towards irradiation and hypoxia-induced cell death. The pLXSN retroviral vector expressed HPV-16E7 genes and was infected into the p53 mutated U87MG cell line. A specific amplification band of HPV16 E7 genes was detected in E7 genes and transfected in the U87MG cell line using a reverse transcriptase polymerase chain reaction. The experimental groups included the mutant glioblastoma cell line (U87MG), empty vector (pLXSN) transfected to mutant glioblastoma cell line (U87MG-LXSN), and retrovirus carrying HPV16 E7 genes transfected to the mutant glioblastoma cell line (U87MG-E7). Hypoxic conditions were optimized using LDH assay and the subjects were exposed to hypoxia (16 and 20 h) and irradiation (9 h). Hoechst-propidium iodide (PI) staining results showed that hypoxia and irradiation increased the number of dead cells in the U87MG-E7 cells compared to U87MG and U87MG-LXSN cells. Results of the FACS analysis showed a similar pattern and recorded 80.44 and 58.94% of apoptotic cells in U87MG-E7 and U87MG cells, respectively. Cell cycle analysis by FACS revealed that, following irradiation and hypoxia, cells showed G2-M arrest. Additionally, the Western blot analysis results showed altered expression of E2F-1, Rb and p53 in the irradiation- and hypoxia-induced U87MG-E7 cells compared to U87MG and U87MG LXSN cells. In conclusion, the over-expression of HPV16 E7 genes in U87MG cell lines increasd cell apoptosis and E2F1 expression compared to the HPV non-infected U87MG cells following irradiation and hypoxia. These results indicate that tumor-specific therapies that increase sensitivity towards radiation and hypoxic conditions may be beneficial for suppression of cancers. PMID:21850378

Moon, Sung-Ung; Choi, Soo Kyoung; Kim, Han Jo; Kumar Bokara, Kiran; Park, Kyung Ah; Lee, Won Taek; Lee, Jong-Eun

2011-08-17

71

p21cip1 Degradation in Differentiated Keratinocytes Is Abrogated by Costabilization with Cyclin E Induced by Human Papillomavirus E7  

PubMed Central

The human papillomavirus (HPV) E7 protein promotes S-phase reentry in a fraction of postmitotic, differentiated keratinocytes. Here we report that these cells contain an inherent mechanism that opposes E7-induced DNA replication. In organotypic raft cultures of primary human keratinocytes, neither cyclin E nor p21cip1 is detectable in situ. However, E7-transduced differentiated cells not in S phase accumulate abundant cyclin E and p21cip1. We show that normally p21cip1 protein is rapidly degraded by proteasomes. In the presence of E7 or E6/E7, p21cip1, cyclin E, and cyclin E2 proteins were all up-regulated. The accumulation of p21cip1 protein is a posttranscriptional event, and ectopic cyclin E expression was sufficient to trigger it. In constract, cdk2 and p27kip1 were abundant in normal differentiated cells and were not significantly affected by E7. Cyclin E, cdk2, and p21cip1 or p27kip1 formed complexes, and relatively little kinase activity was found associated with cyclin E or cdk2. In patient papillomas and E7 raft cultures, all p27kip1-positive cells were negative for bromodeoxyuridine (BrdU) incorporation, but only some also contained cyclin E and p21cip1. In contrast, all cyclin E-positive cells also contained p27kip1. When the expression of p21cip1 was reduced by rottlerin, a PKC ? inhibitor, p27kip1- and BrdU-positive cells remained unchanged. These observations show that high levels of endogenous p27kip1 can prevent E7-induced S-phase reentry. This inhibition then leads to the stabilization of cyclin E and p21cip1. Since efficient initiation of viral DNA replication requires cyclin E and cdk2, its inhibition accounts for heterogeneous viral activities in productively infected lesions.

Noya, Francisco; Chien, Wei-Ming; Broker, Thomas R.; Chow, Louise T.

2001-01-01

72

HPV E6 oncoprotein as a potential therapeutic target in HPV related cancers.  

PubMed

Introduction: Human Papillomaviruses (HPVs) are the main etiological agents for the development of most ano-genital cancers and for a subset of head and neck neoplasias. The oncogenic capacity of HPV is due to the combined activity of the viral oncoproteins E6 and E7. A defining feature of all HPV associated cancers is the continued retention and expression of these two viral oncoproteins throughout the development of the disease, and this highlights their value as potential targets for therapeutic intervention, in HPV-induced malignancies. Areas covered: In this review, the authors focus on the HPV E6 oncoprotein functions and its interactions with cellular targets containing either LxxLL motifs or PDZ domains. New approaches leading to the prevention such interactions are described, showing the advantage of E6 as a target for therapeutic intervention against malignant transformation and cancer. Expert opinion: The high degree of conservation in E6-LxxLL interactions across multiple HPV types makes this a compelling therapeutic target for pathologies caused by diverse HPV types. Combining this with therapeutics directed against E6-PDZ interactions offers great promise for the treatment of malignancies caused by high-risk HPV types. PMID:24094136

Manzo-Merino, Joaquin; Thomas, Miranda; Fuentes-Gonzalez, Alma M; Lizano, Marcela; Banks, Lawrence

2013-10-06

73

Viral recombinant vaccines to the E6 and E7 antigens of HPV-16.  

PubMed

Most cancerous lesions of the uterine cervix are linked to persistent infections with human papillomaviruses (HPV), most notably HPV-16 or -18. Vaccine-induced immune responses to the HPV early antigens E6 and E7, which contribute to cell transformation and are thus expressed in these cervical cancers, could potentially eradicate malignant cells. We generated recombinant vaccines based on E1-deleted adenovirus human strain 5 or on vaccinia virus strain Copenhagen expressing either the E6 or E7 oncoproteins of HPV-16. The different vaccines were compared in two experimental mouse tumor models employing Balb/c or C57Bl/6 mice. Data presented here demonstrate that depending on the model either CD4(+) or CD8(+) T cells provide protection to tumor cell challenge, resulting in striking differences in the efficacy of the four vaccines under investigation. PMID:10772987

He, Z; Wlazlo, A P; Kowalczyk, D W; Cheng, J; Xiang, Z Q; Giles-Davis, W; Ertl, H C

2000-04-25

74

Viral oncoproteins target the DNA methyltransferases.  

PubMed

Small DNA tumour viruses have evolved a number of mechanisms to drive nondividing cells into S phase. Virally encoded oncoproteins such as adenovirus E1A and human papillomavirus (HPV) E7 can bind an array of cellular proteins to override proliferation arrest. The DNA methyltransferase Dnmt1 is the major mammalian enzyme responsible for maintaining CpG methylation patterns in the cell following replication. One of the hallmarks of tumour cells is disrupted DNA methylation patterns, highlighting the importance of the proper regulation of DNA methyltransferases in normal cell proliferation. Here, we show that adenovirus 5 E1A and HPV-16 E7 associate in vitro and in vivo with the DNA methyltransferase Dnmt1. Consistent with this interaction, we find that E1A and E7 can purify DNA methyltransferase activity from nuclear extracts. These associations are direct and mediated by the extreme N-terminus of E1A and the CR3 zinc-finger domain of E7. Furthermore, we find that a point mutant at leucine 20 of E1A, a residue known to be critical for its transformation functions, is unable to bind Dnmt1 and DNA methyltransferase activity. Finally, both E1A and E7 can stimulate the methyltransferase activity of Dnmt1 in vitro. Our results provide the first indication that viral oncoproteins bind and regulate Dnmt1 enzymatic activity. These observations open up the possibility that this association may be used to control cellular proliferation pathways and suggest a new mechanism by which small DNA tumour viruses can steer cells through the cell cycle. PMID:16983344

Burgers, W A; Blanchon, L; Pradhan, S; de Launoit, Y; Kouzarides, T; Fuks, F

2006-09-18

75

Immune responses and therapeutic antitumor effects of an experimental DNA vaccine encoding human papillomavirus type 16 oncoproteins genetically fused to herpesvirus glycoprotein D.  

PubMed

Recombinant adenovirus or DNA vaccines encoding herpes simplex virus type 1 (HSV-1) glycoprotein D (gD) genetically fused to human papillomavirus type 16 (HPV-16) oncoproteins (E5, E6, and E7) induce antigen-specific CD8(+) T-cell responses and confer preventive resistance to transplantable murine tumor cells (TC-1 cells). In the present report, we characterized some previously uncovered aspects concerning the induction of CD8(+) T-cell responses and the therapeutic anticancer effects achieved in C57BL/6 mice immunized with pgD-E7E6E5 previously challenged with TC-1 cells. Concerning the characterization of the immune responses elicited in mice vaccinated with pgD-E7E6E5, we determined the effect of the CD4(+) T-cell requirement, longevity, and dose-dependent activation on the E7-specific CD8(+) T-cell responses. In addition, we determined the priming/boosting properties of pgD-E7E6E5 when used in combination with a recombinant serotype 68 adenovirus (AdC68) vector encoding the same chimeric antigen. Mice challenged with TC-1 cells and then immunized with three doses of pgD-E7E6E5 elicited CD8(+) T-cell responses, measured by intracellular gamma interferon (IFN-?) and CD107a accumulation, to the three HPV-16 oncoproteins and displayed in vivo antigen-specific cytolytic activity, as demonstrated with carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled target cells pulsed with oligopeptides corresponding to the H-2D(b)-restricted immunodominant epitopes of the E7, E6, or E5 oncoprotein. Up to 70% of the mice challenged with 5 × 10(5) TC-1 cells and immunized with pgD-E7E6E5 controlled tumor development even after 3 days of tumor cell challenge. In addition, coadministration of pgD-E7E6E5 with DNA vectors encoding pGM-CSF or interleukin-12 (IL-12) enhanced the therapeutic antitumor effects for all mice challenged with TC-1 cells. In conclusion, the present results expand our previous knowledge on the immune modulation properties of the pgD-E7E6E5 vector and demonstrate, for the first time, the strong antitumor effects of the DNA vaccine, raising promising perspectives regarding the development of immunotherapeutic reagents for the control of HPV-16-associated tumors. PMID:20739505

Diniz, Mariana O; Lasaro, Marcio O; Ertl, Hildegund C; Ferreira, Luís C S

2010-08-25

76

Human papillomavirus type 16/18 oncoproteins: potential therapeutic targets in non-smoking associated lung cancer.  

PubMed

High-risk human papillomavirus (HPV) especially HPV-16 and HPV-18 types are speculated to be important risk factors in non-smoking associated lung cancer in Asia. Increasing evidence has demonstrated that HPV oncoproteins may contribute to lung tumorigenesis and cell transformation. Importantly, HPV 16/18 E6 and E7 oncoproteins can mediate expression of multiple target genes and proteins, such as p53/pRb, VEGF, HIF-1?, cIAP-2, and hTERT, and contribute to cell proliferation, angiogenesis and cell immortalization through different signaling pathways in lung cancer. This article provides an overview of experiment data on HPV-associated lung cancer, describes the main targets on which HPV E6/E7 oncoproteins act, and further discusses the potential signaling pathways in which HPV E6/E7 oncoproteins are involved. In addition, we also raise questions regarding existing problems with the study of HPV-associated lung cancer. PMID:23317184

Zhang, Er-Ying; Tang, Xu-Dong

2012-01-01

77

Human papillomavirus 16-encoded E7 protein inhibits IFN-?-mediated MHC class I antigen presentation and CTL-induced lysis by blocking IRF-1 expression in mouse keratinocytes.  

PubMed

Human papillomavirus 16 (HPV16) infection causes 50?% or more of cervical cancers in women. The HPV16 E7 oncogene is continuously expressed in infected epithelium with its oncogenicity linked to cervical cancer. The E7 protein is an ideal target in control of HPV infection through T-cell-mediated immunity. Using HPV16 E7-transgenic mouse keratinocytes (KCs-E7) to investigate T-cell-mediated immune responses, we have shown previously that HPV16-encoded E7 protein inhibits IFN-?-mediated enhancement of MHC class I antigen processing and T-cell-induced target cell lysis. In this study, we found that HPV16 E7 suppresses IFN-?-induced phosphorylation of STAT1((Tyr701)), leading to the blockade of interferon regulatory factor-1 (IRF-1) and transporter associated antigen processing subunit 1 (TAP-1) expression in KCs-E7. The results of a (51)Cr release assay demonstrated that IFN-?-treated KCs-E7 escaped from CTL recognition because HPV16 E7 downregulated MHC class I antigen presentation on KCs. Restoration of IRF-1 expression in KCs-E7 overcame the inhibitory effect of E7 protein on IFN-?-mediated CTL lysis and MHC class I antigen presentation on KCs. Our results suggest that HPV16 E7 interferes with the IFN-?-mediated JAK1/JAK2/STAT1/IRF-1 signal transduction pathway and reduces the efficiency of peptide loading and MHC class I antigen presentation on KCs-E7. These results may reveal a new mechanism whereby HPV16 escapes from immune surveillance in vivo. PMID:23956301

Zhou, Fang; Chen, Jiezhong; Zhao, Kong-Nan

2013-08-16

78

Human papillomavirus-induced carcinogenesis and the ubiquitin-proteasome system.  

PubMed

Certain types of human papillomaviruses have been etiologically associated with malignant lesions, most notably with cervical cancer. The major oncoproteins of these cancer-associated viruses are encoded by the viral E6 and E7 genes. Thorough characterization of these oncoproteins and their interaction with cellular proteins has shown that both E6 and E7 exploit the ubiquitin-proteasome system to degrade and, thus, to functionally inactivate negative cell-regulatory proteins including members of the p110(RB) family and p53. This act of piracy is assumed to contribute to both the efficient propagation of HPVs and HPV-induced carcinogenesis. PMID:12507557

Scheffner, Martin; Whitaker, Noel J

2003-02-01

79

Long-lasting immunoprotective and therapeutic effects of a hyperstable E7 oligomer based vaccine in a murine human papillomavirus tumor model.  

PubMed

Cervical cancer and many other anogenital and oropharyngeal carcinomas are strongly associated with high-risk human papillomavirus (HPV) persistent infections. HPV E7 oncoprotein is the major viral transforming factor, emerging as a natural candidate for immunotherapy, since it is constitutively expressed in HPV-induced cancer cells. We have previously shown that E7 can self-assemble into soluble and homogeneous spherical oligomers, named E7 soluble oligomers (E7SOs). These are highly resistant to thermal denaturation, providing an additional advantage given the demand for highly stable vaccine formulations. Here, we present a new chemically stabilized form of the E7SOs (E7SOx) and analyzed its effect in a murine HPV-tumor model. Vaccination of female mice with low doses of E7SOx combined with a CpG-rich oligonucleotide (ODN) as adjuvant elicits a strong long-lasting protection against E7-expressing tumor cells, preventing tumor outgrowth after rechallenge 90-days later. Therapeutic experiments showed that E7SOx/ODN vaccination significantly delays tumor growth and extends the time of survival of the treated mice in a dose-dependent manner. These proof-of-principle preclinical experiments denote the potential applicability of our E7SOx-based vaccine to the treatment of cervical cancer and other mucosal HPV-related neoplastic lesions. In addition to thermal, chemical and proteolysis stability, the combined recombinant and chemical modification nature of the E7SOx vaccine candidate, results in low-cost, of particular interest in developing countries, where most of the cervical cancer cases occur and the most affected population is at reproductive age. PMID:21780110

Cerutti, María L; Alonso, Leonardo G; Tatti, Silvio; de Prat-Gay, Gonzalo

2011-08-24

80

The Heat Shock Protein 90Binding Geldanamycin Inhibits Cancer Cell Proliferation, Down-Regulates Oncoproteins, and Inhibits Epidermal Growth Factor Induced Invasion in Thyroid Cancer Cell Lines  

Microsoft Academic Search

Heat shock protein 90 (HSP90) serves as a chaperone protein and plays a critical role in tumor cell growth and\\/or survival. Geldanamycin, a specific inhibitor of HSP90, is cytotoxic to several human cancer cell lines, but its effect in thyroid cancer is unknown. We, therefore, investigated the effect of geldanamycin on cell proliferation, oncoprotein expression, and invasion in human thyroid

JIN-WOO PARK; MICHAEL W. YEH; MARIWIL G. WONG; MARGARET LOBO; WILLIAM C. HYUN; QUAN-YANG DUH; ORLO H. CLARK

81

In VitroAntigene Therapy Targeting HPV16 E6 and E7 in Cervical Carcinoma  

Microsoft Academic Search

Human papillomavirus (HPV) infection is believed to play a central role in cervical carcinogenesis. Specifically, two viral oncoproteins, E6 and E7, possess transforming ability and have been shown to interact with the cellular tumor suppressors p53 and p105, the retinoblastoma (Rb) gene product. To test the hypothesis that E6 and E7 play an active role in the maintenance of the

Marilu Madrigal; Mike F. Janicek; Bernd-Uwe Sevin; James Perras; Ricardo Estape; Manuel Peñalver; Hervy E. Averette

1997-01-01

82

Conserved Region 3 of Human Papillomavirus 16 E7 Contributes to Deregulation of the Retinoblastoma Tumor Suppressor  

PubMed Central

The human papillomavirus (HPV) E7 oncoprotein binds cellular factors, preventing or retargeting their function and thereby making the infected cell conducive for viral replication. A key target of E7 is the product of the retinoblastoma susceptibility locus (pRb). This interaction results in the release of E2F transcription factors and drives the host cell into the S phase of the cell cycle. E7 binds pRb via a high-affinity binding site in conserved region 2 (CR2) and also targets a portion of cellular pRb for degradation via the proteasome. Evidence suggests that a secondary binding site exists in CR3, and that this interaction influences pRb deregulation. Additionally, evidence suggests that CR3 also participates in the degradation of pRb. We have systematically analyzed the molecular mechanisms by which CR3 contributes to deregulation of the pRb pathway by utilizing a comprehensive series of mutations in residues predicted to be exposed on the surface of HPV16 E7 CR3. Despite differences in the ability to interact with cullin 2, all CR3 mutants degrade pRb comparably to wild-type E7. We identified two specific patches of residues on the surface of CR3 that contribute to pRb binding independently of the high-affinity CR2 binding site. Mutants within CR3 that affect pRb binding are less effective than the wild-type E7 in overcoming pRb-induced cell cycle arrest. This demonstrates that the interaction between HPV16 E7 CR3 and pRb is functionally important for alteration of the cell cycle.

Todorovic, Biljana; Hung, Katherine; Massimi, Paola; Avvakumov, Nikita; Dick, Frederick A.; Shaw, Gary S.; Banks, Lawrence

2012-01-01

83

Immunization with Adenoviral Vectors Carrying Recombinant IL-12 and E7 Enhanced the Antitumor Immunity against Human Papillomavirus 16-associated Tumor  

PubMed Central

Purpose Human papillomavirus (HPV) infection has a significant role in cervical carcinogenesis, and HPV oncoprotein E7 plays an important part in the formation and maintenance of cervical cancer. Interleukin-12 (IL-12) has been reported to induce a cellular immune response, and to suppress the tumor growth and the E7 production. Here we describe the use of adenoviral delivery of the HPV 16 E7 subunit (AdE7) along with adenoviral delivery of IL-12 (AdIL-12) in mice with HPV-associated tumors. Materials and Methods Mice were injected with TC-1 cells to establish TC-1 tumor, and then they were immunized with AdIL-12 and/or AdE7 intratumorally. The anti tumor effects induced by AdIL-12 and/or E7 were evaluated by measuring the size of the tumor. E7-specific antibody and INF-? production in sera, and the T-helper cell proliferative responses were then measured. Cytotoxic T-lymphocyte (CTL) and T cell subset depletion studies were also performed. Results Combined AdIL-12 and AdE7 infection at the tumor sites significantly enhanced the antitumor effects more than that of AdIL-12 or AdE7 single infection. This combined infection resulted in regression of the 9 mm sized tumors in 80% of animals as compare to the PBS group. E7-specific antibody and INF-? production in the sera, and the T-helper cell proliferative responses were significantly higher with coinfection of AdIL-12 and AdE7 than with AdIL-12 or AdE7 alone. CTL response induced by AdIL-12 and AdE7 in the coinjected group suggested that tumor suppression was mediated by mostly CD8+ and only a little by the CD4+ T cells. Conclusion IL-12 and E7 application using adenovirus vector showed antitumor immunity effects against TC-1 tumor, and this system could be use in clinical applications for HPV-associated cancer. (ED note: nice abstract.)

Park, Eun-Kyung; Kim, Young-Wook; Lee, Joon-Mo; NamKoong, Sung-Eun; Kim, Do-Gang; Chun, Heung-Jae; Han, Byoung-Don; Bae, Su-Mi; Jin, Hyun-Sun; Sin, Jeong-Im

2005-01-01

84

Human papillomavirus 16 E6, E7 siRNAs inhibit proliferation and induce apoptosis of SiHa cervical cancer cells  

Microsoft Academic Search

Objective  To evaluate the effects of HPV16 E6\\/E7 siRNAs on cervical cancer SiHa cells.\\u000a \\u000a \\u000a \\u000a Methods  The expressions of the E6, E7, p53 and Rb genes were assayed by RT-PCR and Western-bloting respectively. The proliferation\\u000a and apoptosis of the cells were evaluated by MTT and flow cytometry.\\u000a \\u000a \\u000a \\u000a Results  HPV 16 E6 and E7 oncogenes were selectivly downregulated by HPV 16 E6 and E7 siRNAs,

Chun-lian Nie; Guo-lan Gao; Jie Han; Hua Li; He-ping Chen; Ming He

2008-01-01

85

Human papillomavirus type 16 mutant E7 protein induces oncogenic transformation via up-regulation of cyclin A and cdc25A  

Microsoft Academic Search

A new mutant human papillomavirus type 16 E7 gene, termed HPV16 HBE7, was isolated from cervical carcinoma biopsy samples\\u000a from patients in an area with high incidence of cervical cancer (Hubei province, China). A previous study showed that the\\u000a HPV16 HBE7 protein was primarily cytoplasmic while wild-type HPV16 E7 protein, termed HPV16 WE7, was concentrated in the nucleus.\\u000a With the

Jin-hua Liu; Yu-liang Zhang; Li-qin Zhu; Yin-yu Xu; Min Zhao; Xin-xing Wu

2008-01-01

86

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

87

Development of spontaneous hyperplastic skin lesions and chemically induced skin papillomas in transgenic mice expressing human papillomavirus type 16 E6\\/E7 genes  

Microsoft Academic Search

Human papillomavirus type 16 (HPV16) has been known to be the major factor for the development of uterine cervical carcinomas. We have developed a line of transgenic mice that express the HPV16 E6 and E7 genes in certain organs using a fusion gene which consists of the tyrosinase promoter and E6\\/E7 of HPV16, and have chosen the tyrosinase minigene as

Jae-Ku Kang; Jong-Ho Kim; Seong-Hak Lee; Dal-Hyun Kim; Hyun-Su Kim; Jong-Eun Lee; Jeong-Sun Seo

2000-01-01

88

Gene gun-mediated DNA vaccination induces antitumor immunity against human papillomavirus type 16 E7-expressing murine tumor metastases in the liver and lungs  

Microsoft Academic Search

DNA vaccination has emerged as an attractive approach for tumor immunotherapy. The aim of this study was to evaluate the potency of DNA vaccines in preventing and treating the liver and lung metastases of a human papillomavirus-16 (HPV-16) E7-expressing murine tumor (TC-1). We used the gene gun method to vaccinate C57BL\\/6 mice intradermally with DNA vaccines containing the HPV-16 E7

C-H Chen; H Ji; K W Suh; M A Choti; D M Pardoll; T-C Wu

1999-01-01

89

The histone deacetylase SIRT2 stabilizes Myc oncoproteins.  

PubMed

Myc oncoproteins are commonly upregulated in human cancers of different organ origins, stabilized by Aurora A, degraded through ubiquitin-proteasome pathway-mediated proteolysis, and exert oncogenic effects by modulating gene and protein expression. Histone deacetylases are emerging as targets for cancer therapy. Here we demonstrated that the class III histone deacetylase SIRT2 was upregulated by N-Myc in neuroblastoma cells and by c-Myc in pancreatic cancer cells, and that SIRT2 enhanced N-Myc and c-Myc protein stability and promoted cancer cell proliferation. Affymetrix gene array studies revealed that the gene most significantly repressed by SIRT2 was the ubiquitin-protein ligase NEDD4. Consistent with this finding, SIRT2 repressed NEDD4 gene expression by directly binding to the NEDD4 gene core promoter and deacetylating histone H4 lysine 16. Importantly, NEDD4 directly bound to Myc oncoproteins and targeted Myc oncoproteins for ubiquitination and degradation, and small-molecule SIRT2 inhibitors reactivated NEDD4 gene expression, reduced N-Myc and c-Myc protein expression, and suppressed neuroblastoma and pancreatic cancer cell proliferation. Additionally, SIRT2 upregulated and small-molecule SIRT2 inhibitors decreased Aurora A expression. Our data reveal a novel pathway critical for Myc oncoprotein stability, and provide important evidences for potential application of SIRT2 inhibitors for the prevention and therapy of Myc-induced malignancies. PMID:23175188

Liu, P Y; Xu, N; Malyukova, A; Scarlett, C J; Sun, Y T; Zhang, X D; Ling, D; Su, S-P; Nelson, C; Chang, D K; Koach, J; Tee, A E; Haber, M; Norris, M D; Toon, C; Rooman, I; Xue, C; Cheung, B B; Kumar, S; Marshall, G M; Biankin, A V; Liu, T

2012-11-23

90

Destabilization of the Retinoblastoma Tumor Suppressor by Human Papillomavirus Type 16 E7 Is Not Sufficient To Overcome Cell Cycle Arrest in Human Keratinocytes  

PubMed Central

The E7 oncoprotein of human papillomavirus type 16 promotes cell proliferation in the presence of antiproliferative signals. Mutagenesis of E7 has revealed that this activity requires three regions, conserved regions 1 and 2 and a C-terminal zinc finger. Binding to the retinoblastoma tumor repressor (Rb) through an LxCxE motif in conserved region 2 is necessary, but not sufficient, for E7 to induce proliferation. We tested the hypothesis that binding to Rb is not sufficient because conserved region 1 and/or the C terminus are required for E7 to functionally inactivate Rb and thus induce proliferation. One mechanism proposed for how E7 inactivates Rb is by blocking Rb-E2F binding. Either conserved region 1 or the C terminus was necessary, in combination with the LxCxE motif, for E7 to block Rb-E2F binding in vitro. While all full-length E7 proteins with mutations outside of the LxCxE motif inhibited Rb-E2F binding, some failed to abrogate cell cycle arrest, demonstrating that blocking Rb-E2F binding is not sufficient for abrogating antiproliferative signals. Another mechanism proposed for how E7 inactivates Rb is by promoting the destabilization of Rb protein. Mutations in conserved region 1 or the LxCxE motif prevented E7 from reducing the half-life of Rb. Though no specific C-terminal residues of E7 were essential for destabilizing Rb, a novel class of mutations that uncouple the destabilization of Rb from the deregulation of keratinocyte proliferation was discovered. Destabilization of Rb correlated with the abrogation of Rb-induced quiescence but was not sufficient for overriding DNA damage-induced cell cycle arrest or for increasing keratinocyte life span. Finally, the same regions of E7 required for destabilizing Rb were required for reducing p107 and p130 levels. Together, these results suggest that inactivation of all three Rb family members is not sufficient to deregulate keratinocyte cell cycle control.

Helt, Anna-Marija; Galloway, Denise A.

2001-01-01

91

Papillomavirus E5: the smallest oncoprotein with many functions  

PubMed Central

Papillomaviruses (PVs) are established agents of human and animal cancers. They infect cutaneous and mucous epithelia. High Risk (HR) Human PVs (HPVs) are consistently associated with cancer of the uterine cervix, but are also involved in the etiopathogenesis of other cancer types. The early oncoproteins of PVs: E5, E6 and E7 are known to contribute to tumour progression. While the oncogenic activities of E6 and E7 are well characterised, the role of E5 is still rather nebulous. The widespread causal association of PVs with cancer makes their study worthwhile not only in humans but also in animal model systems. The Bovine PV (BPV) system has been the most useful animal model in understanding the oncogenic potential of PVs due to the pivotal role of its E5 oncoprotein in cell transformation. This review will highlight the differences between HPV-16 E5 (16E5) and E5 from other PVs, primarily from BPV. It will discuss the targeting of E5 as a possible therapeutic agent.

2011-01-01

92

A combination of DNA vaccines targeting human papillomavirus type 16 E6 and E7 generates potent antitumor effects  

Microsoft Academic Search

Human papillomavirus (HPV) infects large numbers of women worldwide and is present in more than 99% of all cervical cancers. HPV E6 and E7 are two viral oncoproteins that are consistently expressed in HPV infections and HPV-associated malignancies. We have previously developed DNA vaccines encoding calreticulin (CRT) linked either to HPV type 16 (HPV-16) E6 or to HPV-16 E7, both

S Peng; T T Tomson; C Trimble; L He; C-F Hung; T-C Wu

2006-01-01

93

Cluster intradermal DNA vaccination rapidly induces E7-specific CD8+ T-cell immune responses leading to therapeutic antitumor effects  

Microsoft Academic Search

Intradermal administration of DNA vaccines via a gene gun represents a feasible strategy to deliver DNA directly into the professional antigen-presenting cells (APCs) in the skin. This helps to facilitate the enhancement of DNA vaccine potency via strategies that modify the properties of APCs. We have previously demonstrated that DNA vaccines encoding human papillomavirus type 16 (HPV-16) E7 antigen linked

S Peng; C Trimble; R D Alvarez; W K Huh; Z Lin; A Monie; C-F Hung; T-C Wu

2008-01-01

94

HPV16 oncogenes E6 and E7 are mutagenic in normal human oral keratinocytes  

Microsoft Academic Search

The mutation frequency of pS189 shuttle vector plasmids is higher in human oral keratinocytes (NHOK) immortalized with cloned human papillomavirus-16 (HPV-16) genome than in primary normal NHOK (NHOK). To determine whether oncoproteins E6 and E7 of HPV-16 are responsible for the higher mutation frequency of the plasmids, we measured the mutation frequency in NHOK and in NHOK expressing the HPV-16

Xuan Liu; Simon Han; Marcel A Baluda; No-Hee Park; N-H Park

1997-01-01

95

Skin hyperproliferation and susceptibility to chemical carcinogenesis in transgenic mice expressing E6 and E7 of human papillomavirus type 38.  

PubMed

The oncoproteins E6 and E7 of human papillomavirus type 38 (HPV38) display several transforming activities in vitro, including immortalization of primary human keratinocytes. To evaluate the oncogenic activities of the viral proteins in an in vivo model, we generated transgenic mice expressing HPV38 E6 and E7 under the control of the bovine homologue of the human keratin 10 (K10) promoter. Two distinct lines of HPV38 E6/E7-expressing transgenic mice that express the viral genes at different levels were obtained. In both lines, HPV38 E6 and E7 induced cellular proliferation, hyperplasia, and dysplasia in the epidermis. The rate of occurrence of these events was proportional to the levels of HPV38 E6 and E7 expression in the two transgenic lines. Exposure of the epidermis of nontransgenic mice to UV led to p21WAF1 accumulation and cell cycle arrest. In contrast, keratinocytes from transgenic mice continued to proliferate and were not positive for p21WAF1, indicating that cell cycle checkpoints are altered in keratinocytes expressing the viral genes. Although the HPV38 E6/E7-expressing transgenic mice did not develop spontaneous tumors during their life span, two-stage carcinogen treatment led to a high incidence of papillomas, keratoacanthomas, and squamous-cell carcinomas in HPV38 mice compared with nontransgenic animals. Together, these data show that HPV38 E6 and E7 display transforming properties in vivo, providing further support for the role of HPV38 in carcinogenesis. PMID:16282489

Dong, Wen; Kloz, Ulrich; Accardi, Rosita; Caldeira, Sandra; Tong, Wei-Min; Wang, Zhao-Qi; Jansen, Lars; Dürst, Matthias; Sylla, Bakary S; Gissmann, Lutz; Tommasino, Massimo

2005-12-01

96

MUC1-C Oncoprotein Induces TCF7L2 Transcription Factor Activation and Promotes Cyclin D1 Expression in Human Breast Cancer Cells*  

PubMed Central

MUC1 is a heterodimeric glycoprotein that is overexpressed in breast cancers. The present studies demonstrate that the oncogenic MUC1 C-terminal subunit (MUC1-C) associates with the TCF7L2 transcription factor. The MUC1-C cytoplasmic domain (MUC1-CD) binds directly to the TCF7L2 C-terminal region. MUC1-C blocks the interaction between TCF7L2 and the C-terminal-binding protein (CtBP), a suppressor of TCF7L2-mediated transcription. TCF7L2 and MUC1-C form a complex on the cyclin D1 gene promoter and MUC1-C promotes TCF7L2-mediated transcription by the recruitment of ?-catenin and p300. Silencing MUC1-C in human breast cancer cells down-regulated activation of the cyclin D1 promoter and decreased cyclin D1 expression. In addition, a MUC1-C inhibitor blocked the interaction with TCF7L2 and suppressed cyclin D1 levels. These findings indicate that the MUC1-C oncoprotein contributes to TCF7L2 activation and thereby promotes cyclin D1 expression in breast cancer cells.

Rajabi, Hasan; Ahmad, Rehan; Jin, Caining; Kosugi, Michio; Alam, Maroof; Joshi, Maya Datt; Kufe, Donald

2012-01-01

97

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

98

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.

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

99

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.

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

2013-01-01

100

Human papillomavirus type 16 E5 oncoprotein as a new target for cervical cancer treatment.  

PubMed

Human papillomavirus (HPV) infection is considered to be the necessary cause of cervical cancer. E6 and E7 oncoproteins of HPV have been known to play major roles in malignant transformation of cervical cells, inhibiting the tumor suppressors p53 and Rb. However, the role of E5 oncoprotein has been relatively less defined. HPV 16 E5 is a hydrophobic membrane-bound protein which associates with the Golgi apparatus, endoplasmic reticulum and perinuclear membrane. Accumulating evidences have suggested that E5 oncoprotein may also contribute to cervical carcinogenesis through modulating cellular signaling pathways in addition to augmenting the immortalization potential of E6 and E7. Multiple mechanisms, including activation of EGFR or inflammatory cell signaling pathway, have been implicated in malignant transformation by HPV 16 E5. Therefore, targeting E5 may be a rational approach for chemoprevention and treatment of cervical cancer, and understanding its oncogenic processes may help us to design novel therapeutic strategies. In this review, we discussed the roles of HPV 16 E5 in cervical carcinogenesis, altering several cellular signaling pathways involved in cell proliferation, angiogenesis and apoptosis. PMID:20643111

Kim, Mi-Kyung; Kim, Hee Seung; Kim, Su-Hyeong; Oh, Jung-Min; Han, Jae Yong; Lim, Jeong Mook; Juhnn, Yong-Sung; Song, Yong-Sang

2010-07-17

101

Expression of a Single, Viral Oncoprotein in Skin Epithelium Is Sufficient to Recruit Lymphocytes  

PubMed Central

Established cancers are frequently associated with a lymphocytic infiltrate that fails to clear the tumour mass. In contrast, the importance of recruited lymphocytes during premalignancy is less well understood. In a mouse model of premalignant skin epithelium, transgenic mice that express the human papillomavirus type 16 (HPV16) E7 oncoprotein under a keratin 14 promoter (K14E7 mice) display epidermal hyperplasia and have a predominant infiltrate of lymphocytes consisting of both CD4 and CD8 T cells. Activated, but not naïve T cells, were shown to preferentially traffic to hyperplastic skin with an increased frequency of proliferative CD8+ T cells and CD4+ T cells expressing CCR6 within the tissue. Disruption of the interaction between E7 protein and retinoblastoma tumour suppressor protein (pRb) led to reduced epithelial hyperplasia and T cell infiltrate. Finally, while K14E7 donor skin grafts are readily accepted onto syngeneic, non-transgenic recipients, these same skin grafts lacking skin-resident lymphocytes were rejected. Our data suggests that expression of a single oncoprotein in the epidermis is sufficient for lymphocyte trafficking (including immunosuppressive lymphocytes) to premalignant skin.

Narayan, Sharmal; Mattarollo, Stephen R.; Liem, Amy; Lambert, Paul F.; Frazer, Ian H.; Leggatt, Graham R.

2013-01-01

102

SA4-1BBL as the immunomodulatory component of a HPV16 E7 protein based vaccine shows robust therapeutic efficacy in a mouse cervical cancer model  

Microsoft Academic Search

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

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

2010-01-01

103

Skin Hyperproliferation and Susceptibility to Chemical Carcinogenesis in Transgenic Mice Expressing E6 and E7 of Human Papillomavirus Type 38  

Microsoft Academic Search

The oncoproteins E6 and E7 of human papillomavirus type 38 (HPV38) display several transforming activities in vitro, including immortalization of primary human keratinocytes. To evaluate the oncogenic activities of the viral proteins in an in vivo model, we generated transgenic mice expressing HPV38 E6 and E7 under the control of the bovine homologue of the human keratin 10 (K10) promoter.

Wen Dong; Ulrich Kloz; Rosita Accardi; Sandra Caldeira; Wei-Min Tong; Zhao-Qi Wang; Lars Jansen; Matthias Durst; Bakary S. Sylla; Lutz Gissmann; Massimo Tommasino

2005-01-01

104

Large-scale analysis of protein expression changes in human keratinocytes immortalized by human papilloma virus type 16 E6 and E7 oncogenes  

Microsoft Academic Search

BACKGROUND: Infection with high-risk type human papilloma viruses (HPVs) is associated with cervical carcinomas and with a subset of head and neck squamous cell carcinomas. Viral E6 and E7 oncogenes cooperate to achieve cell immortalization by a mechanism that is not yet fully understood. Here, human keratinocytes were immortalized by long-term expression of HPV type 16 E6 or E7 oncoproteins,

Mark A Merkley; Ellen Hildebrandt; Robert H Podolsky; Hilal Arnouk; Daron G Ferris; William S Dynan; Hubert Stöppler

2009-01-01

105

Immunization strategy against cervical cancer involving an alphavirus vector expressing high levels of a stable fusion protein of human papillomavirus 16 E6 and E7  

Microsoft Academic Search

We are developing immunization strategies against cervical carcinoma and premalignant disease, based on the use of recombinant Semliki Forest virus (SFV) encoding the oncoproteins E6 and E7 from high-risk human papilloma viruses (HPV). Thus far, protein-based, as well as genetic immunization studies have demonstrated low to moderate cellular immune responses against E6 and E7. To improve these responses, we modified

T Daemen; J Regts; M Holtrop; J Wilschut

2002-01-01

106

Disruption of the G1\\/S Transition in Human Papillomavirus Type 16 E7Expressing Human Cells Is Associated with Altered Regulation of Cyclin E  

Microsoft Academic Search

The development of neoplasia frequently involves inactivation of the p53 and retinoblastoma (Rb) tumor suppressor pathways and disruption of cell cycle checkpoints that monitor the integrity of replication and cell division. The human papillomavirus type 16 (HPV-16) oncoproteins, E6 and E7, have been shown to bind p53 and Rb, respectively. To further delineate the mechanisms by which E6 and E7

LARRY G. MARTIN; G. WILLIAM DEMERS; DENISE A. GALLOWAY

1998-01-01

107

Human Papillomavirus Type 16 E7 Peptide-Directed CD8+ T Cells from Patients with Cervical Cancer Are Cross-Reactive with the Coronavirus NS2 Protein  

Microsoft Academic Search

Human papillomavirus type 16 (HPV16) E6 and E7 oncoproteins are required for cellular transformation and represent candidate targets for HPV-specific and major histocompatibility complex class I-restricted CD8-T-cell responses in patients with cervical cancer. Recent evidence suggests that cross-reactivity repre- sents the inherent nature of the T-cell repertoire. We identified HLA-A2 binding HPV16 E7 variant peptides from human, bacterial, or viral

Katja Nilges; Hanni Hohn; Henryk Pilch; Claudia Neukirch; Kirsten Freitag; P. J. Talbot; Markus J. Maeurer

2003-01-01

108

Expression of soluble TGF-? receptor II by recombinant Vaccinia virus enhances E7 specific immunotherapy of HPV16 tumors.  

PubMed

Therapeutic immunization with double recombinants of vaccinia virus (VACV) co-expressing sT?RII increased rejection of established TC-1 tumors in C57BL/6 mice in comparison with single recombinant expressing SigE7LAMP. Recombinant VACV derived from vaccination strain Praha expressed either the sT?RII (ectodomain) or chimeric protein fused to immunoglobulin Fc fragment (sT?RII-Fc-Jun) under control of two different promotors together with the immunogenic tumor associated antigen HPV16 E7 oncoprotein in a form of SigE7LAMP fusion molecule. The ability of soluble receptors to bind TGF-? in vitro was proved. Immunization of mice with double recombinant viruses and virus expressing SigE7LAMP only led to eliciting similar response of E7 specific CD8+ T cells as detected by IFN-? ELISPOT. PMID:21391733

Zurkova, K; Chlanda, P; Samkova, Z; Babiarova, K; Kutinova, L; Krystofova, J; Hainz, P; Nemeckova, S

2011-01-01

109

KIT oncoprotein interactions in gastrointestinal stromal tumors: therapeutic relevance  

Microsoft Academic Search

Most gastrointestinal stromal tumors (GISTs) express oncogenic and constitutively active forms of the KIT or platelet-derived growth factor receptor alpha (PDGFRA) receptor tyrosine kinase proteins, and these kinase oncoproteins serve as targets for effective therapies. Given that mutant KIT oncoproteins serve crucial transforming roles in GISTs, we evaluated interactions with the KIT oncoproteins and determined signaling pathways that are dependent

M-J Zhu; W-B Ou; C D M Fletcher; P S Cohen; G D Demetri; J A Fletcher

2007-01-01

110

Kaposi's Sarcoma-Associated Herpesvirus Oncoprotein K13 Protects against B Cell Receptor-Induced Growth Arrest and Apoptosis through NF-?B Activation  

PubMed Central

Kaposi's sarcoma-associated herpesvirus (KSHV) has been linked to the development of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease (MCD). We have characterized the role of KSHV-encoded viral FLICE inhibitory protein (vFLIP) K13 in the modulation of anti-IgM-induced growth arrest and apoptosis in B cells. We demonstrate that K13 protects WEHI 231, an immature B-cell line, against anti-IgM-induced growth arrest and apoptosis. The protective effect of K13 was associated with the activation of the NF-?B pathway and was deficient in a mutant K13 with three alanine substitutions at positions 58 to 60 (K13-58AAA) and a structural homolog, vFLIP E8, both of which lack NF-?B activity. K13 upregulated the expression of NF-?B subunit RelB and blocked the anti-IgM-induced decline in c-Myc and rise in p27Kip1 that have been associated with growth arrest and apoptosis. K13 also upregulated the expression of Mcl-1, an antiapoptotic member of the Bcl2 family. Finally, K13 protected the mature B-cell line Ramos against anti-IgM-induced apoptosis through NF-?B activation. Inhibition of anti-IgM-induced apoptosis by K13 may contribute to the development of KSHV-associated lymphoproliferative disorders.

Graham, Ciaren; Matta, Hittu; Yang, Yanqiang; Yi, Han; Suo, Yulan; Tolani, Bhairavi

2013-01-01

111

A Fission Yeast Homolog of Int-6, the Mammalian Oncoprotein and eIF3 Subunit, Induces Drug Resistance when Overexpressed  

PubMed Central

Through a screen to identify genes that induce multi-drug resistance when overexpressed, we have identified a fission yeast homolog of Int-6, a component of the human translation initiation factor eIF3. Disruption of the murine Int-6 gene by mouse mammary tumor virus (MMTV) has been implicated previously in tumorigenesis, although the underlying mechanism is not yet understood. Fission yeast Int6 was shown to interact with other presumptive components of eIF3 in vivo, and was present in size fractions consistent with its incorporation into a 43S translation preinitiation complex. Drug resistance induced by Int6 overexpression was dependent on the AP-1 transcription factor Pap1, and was associated with increased abundance of Pap1-responsive mRNAs, but not with Pap1 relocalization. Fission yeast cells lacking the int6 gene grew slowly. This growth retardation could be corrected by the expression of full length Int6 of fission yeast or human origin, or by a C-terminal fragment of the fission yeast protein that also conferred drug resistance, but not by truncated human Int-6 proteins corresponding to the predicted products of MMTV-disrupted murine alleles. Studies in fission yeast may therefore help to explain the ways in which Int-6 function can be perturbed during MMTV-induced mammary tumorigenesis.

Crane, Richard; Craig, Randa; Murray, Rachael; Dunand-Sauthier, Isabelle; Humphrey, Tim; Norbury, Chris

2000-01-01

112

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

PubMed Central

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.

Wang, Xin; Qi, Mei; Yu, Xiuping

2012-01-01

113

Autocrine CCL3 and CCL4 induced by the oncoprotein LMP1 promote Epstein-Barr virus-triggered B cell proliferation.  

PubMed

Epstein-Barr virus (EBV) alters the regulation and expression of a variety of cytokines in its host cells to modulate host immune surveillance and facilitate viral persistence. Using cytokine antibody arrays, we found that, in addition to the cytokines reported previously, two chemotactic cytokines, CCL3 and CCL4, were induced in EBV-infected B cells and were expressed at high levels in all EBV-immortalized lymphoblastoid cell lines (LCLs). Furthermore, EBV latent membrane protein 1 (LMP1)-mediated Jun N-terminal protein kinase activation was responsible for upregulation of CCL3 and CCL4. Inhibition of CCL3 and CCL4 in LCLs using a short hairpin RNA approach or by neutralizing antibodies suppressed cell proliferation and caused apoptosis, indicating that autocrine CCL3 and CCL4 are required for LCL survival and growth. Importantly, significant amounts of CCL3 were detected in EBV-positive plasma from immunocompromised patients, suggesting that EBV modulates this chemokine in vivo. This study reveals the regulatory mechanism and a novel function of CCL3 and CCL4 in EBV-infected B cells. CCL3 might be useful as a therapeutic target in EBV-associated lymphoproliferative diseases and malignancies. PMID:23760235

Tsai, Shu-Chun; Lin, Sue-Jane; Lin, Cheau-Jye; Chou, Ya-Ching; Lin, Jiun-Han; Yeh, Te-Huei; Chen, Mei-Ru; Huang, Li-Min; Lu, Meng-You; Huang, Ya-Chi; Chen, Huan-Yun; Tsai, Ching-Hwa

2013-06-12

114

Expression of CD56 by human papillomavirus E7-specific CD8+ cytotoxic T lymphocytes correlates with increased intracellular perforin expression and enhanced cytotoxicity against HLA-A2-matched cervical tumor cells.  

PubMed

Human papillomavirus (HPV) infection represents the most important risk factor for developing cervical cancer. In this study, we examine the potential of full-length E7-pulsed autologous dendritic cells (DCs) to induce antigen-specific CTL responses from the peripheral blood of healthy individuals against HLA-A2-matched HPV-16 and HPV-18-positive tumor target cells in vitro. We show that DCs pulsed with E7 oncoprotein can consistently stimulate antigen-specific CTL responses that recognize and lyse HPV-16 or HPV-18-positive naturally infected cervical cancer cell lines. HPV-negative, EBV-transformed lymphoblastoid cell lines (LCLs) sharing the HLA haplotype of the target tumor cells, as well as autologous donor LCLs, were not significantly killed by E7-specific CTLs. Cytotoxicity against HLA-A2-matched HPV-16 and HPV-18 tumor target cells could be significantly inhibited by anti-HLA class I and by anti-HLA-A2 monoclonal antibodies. CD8+ CTLs expressed variable levels of CD56 and showed a strongly polarized Type 1 cytokine profile. Sorting of the CD8+ T cells on the basis of CD56 expression demonstrated that the most highly cytotoxic CTLs were CD56+ and expressed higher levels of perforin and IFN-gamma, compared with the CD8+/CD56- population. Taken together, these data demonstrate that full-length, E7-pulsed DCs can consistently induce E7-specific CD8+ CTL responses in healthy individuals that are able to kill naturally HPV-16 and HPV-18-infected cancer cells, and that CD56 expression defines a subset of CD8+ CTLs with high cytolytic activity against tumor cells. PMID:11300476

Santin, A D; Hermonat, P L; Ravaggi, A; Bellone, S; Roman, J J; Jayaprabhu, S; Pecorelli, S; Parham, G P; Cannon, M J

2001-03-01

115

Activated Notch1 Inhibits p53-Induced Apoptosis and Sustains Transformation by Human Papillomavirus Type 16 E6 and E7 Oncogenes through a PI3K-PKB/Akt-Dependent Pathway  

PubMed Central

Activated Notch1 (AcN1) alleles cooperate with oncogenes from DNA tumor viruses in transformation of epithelial cells. AcN1 signaling has pleiotropic effects, and suggested oncogenic roles include driving proliferation through cyclin D1 or the generation of resistance to apoptosis on matrix withdrawal through a phosphatidylinositol 3-kinase (PI3K)-PKB/Akt-dependent pathway. Here, we extend the antiapoptotic role for AcN1 by showing inhibition of p53-induced apoptosis and transactivation. Chemical inhibitors of the PI3K pathway block AcN1-induced inhibition of p53-dependent apoptosis and nuclear localization of Hdm2. We show that expression of wild-type p53 does not inhibit synergistic transformation by AcN1 and human papillomavirus E6 and E7 oncogenes. We suggest that activation of Notch signaling may serve as an additional mechanism to inhibit wild-type p53 function in papillomavirus-associated neoplasia.

Nair, Pradip; Somasundaram, Kumaravel; Krishna, Sudhir

2003-01-01

116

Generation of tumor-specific cytolytic T lymphocytes from peripheral blood of cervical cancer patients by in vitro stimulation with a synthetic human papillomavirus type 16 E7 epitope  

Microsoft Academic Search

OBJECTIVE: Approximately 90% of squamous carcinomas of the cervix harbor the human papillomavirus and type 16 has been detected in nearly 50% of cases. Recent studies in mice have shown that the human papillomavirus type 16 E7 oncoprotein contains peptide epitopes that are processed and presented in association with a major histocompatibility antigen for recognition by cytolytic T lymphocytes. We

Margaret Alexander; Michael L. Salgaller; Esteban Celis; Alessandro Sette; Willard A. Barnes; Steven A. Rosenberg; Michael A. Steller

1996-01-01

117

Induction of Human Papillomavirus-Specific CD4 1 and CD8 1 Lymphocytes by E7Pulsed Autologous Dendritic Cells in Patients with Human Papillomavirus Type 16- and 18Positive Cervical Cancer  

Microsoft Academic Search

Human papillomavirus (HPV) type 16 (HPV 16) and HPV type 18 (HPV 18) are implicated in the induction and progression of the majority of cervical cancers. Since the E6 and E7 oncoproteins of these viruses are expressed in these lesions, such proteins might be potential tumor-specific targets for immunotherapy. In this report, we demonstrate that recombinant, full-length E7-pulsed autologous dendritic

ALESSANDRO D. SANTIN; PAUL L. HERMONAT; ANTONELLA RAVAGGI; MAURIZIO CHIRIVA-INTERNATI; DEJIN ZHAN; SERGIO PECORELLI; GROESBECK P. PARHAM; MARTIN J. CANNON

1999-01-01

118

Preclinical safety and efficacy of TA-CIN, a recombinant HPV16 L2E6E7 fusion protein vaccine, in homologous and heterologous prime-boost regimens  

Microsoft Academic Search

Human papillomavirus (HPV) E6 and E7 oncoproteins are attractive targets for T-cell-based immunotherapy of cervical intraepithelial neoplasia (CIN) and cancer. A newly designed vaccine, comprising the HPV16 L2, E6 and E7 as a single fusion protein (TA-CIN), was shown to elicit HPV16-specific CTL, T-helper cells and antibodies in a pre-clinical mouse model. These immune responses effectively prevented outgrowth of HPV16-positive

S. H. van der Burg; K. M. C. Kwappenberg; T. O'Neill; R. M. P. Brandt; C. J. M. Melief; J. K. Hickling; R. Offringa

2001-01-01

119

A prime/boost strategy by DNA/fowlpox recombinants expressing a mutant E7 protein for the immunotherapy of HPV-associated cancers.  

PubMed

Development of effective therapeutic vaccines against human papilloma virus (HPV) infections remains a priority, considering the high number of new cases of cervical cancer each year by high-risk HPVs, in particular by HPV-16. Vaccines expressing the E7 oncoprotein, which is detectable in all HPV-positive pre-cancerous and cancer cells, might clear already established tumors and support the treatment of HPV-related lesions. In this study, DNA or fowlpox virus recombinants expressing the harmless variant E7GGG of the HPV-16 E7 oncoprotein (DNA(E7GGG) and FP(E7GGG)) were generated. Two immunization regimens were tested in a pre-clinical mouse model by homologous (FP/FP) or heterologous (DNA/FP) prime-boost protocols to evaluate the immune response and therapeutic efficacy of the proposed HPV-16 vaccine. Low levels of anti-E7-specific antibodies were elicited after immunization, and in vivo experiments resulted in a higher number of tumor-free mice after the heterologous immunization. These results establish a preliminary indication for therapy of HPV-related tumors by the combined use of DNA and avipox recombinants, which might represent safer immunogens than vaccinia-based vaccines. PMID:22951311

Radaelli, Antonia; De Giuli Morghen, Carlo; Zanotto, Carlo; Pacchioni, Sole; Bissa, Massimiliano; Franconi, Rosella; Massa, Silvia; Paolini, Francesca; Muller, Antonio; Venuti, Aldo

2012-08-19

120

Fowlpox virus recombinants expressing HPV16 E6 and E7 oncogenes for the therapy of cervical carcinoma elicit humoral and cell-mediated responses in rabbits  

Microsoft Academic Search

BACKGROUND: Around half million new cases of cervical cancer arise each year, making the development of an effective therapeutic vaccine against HPV a high priority. As the E6 and E7 oncoproteins are expressed in all HPV-16 tumour cells, vaccines expressing these proteins might clear an already established tumour and support the treatment of HPV-related precancerous lesions. METHODS: Three different immunisation

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

2010-01-01

121

Prophylactic, therapeutic and anti-metastatic effects of an HPV16 mE6?\\/mE7\\/TBhsp70? fusion protein vaccine in an animal model  

Microsoft Academic Search

Human papillomaviruses (HPVs), particularly HPV-16, are not only causally linked to cervical cancers but also play an important role in the development of other cancers. The oncoproteins, E6 and E7, are consistently coexpressed in the majority of HPV-containing carcinomas and their metastatic lesions, and are critical to the induction and maintenance of malignant phenotype, and also can cause tumor metastasis.

Xinlai Qian; Yuanzhi Lu; Qiao Liu; Ke Chen; Qingzheng Zhao; Jietao Song

2006-01-01

122

Bovine papillomavirus oncoprotein E5 affects the arachidonic acid metabolism in cells  

Microsoft Academic Search

The bovine papillomavirus type 1 (BPV-1) oncoprotein encoded by the E5 ORF is a small highly hydrophobic protein, which is capable of inducing oncogenic transformation of cells. We studied the effect of the BPV-1 E5 protein expression on the arachidonic acid metabolism in monkey (COS1) and human (C33A) cells. At relatively low protein concentrations the phospholipase A2 (PLA2) activity and

Ülo Väli; Ann Kilk; Mart Ustav

2001-01-01

123

Cutaneous Papillomavirus E6 oncoproteins associate with MAML1 to repress transactivation and NOTCH signaling  

PubMed Central

Papillomavirus E6 oncoproteins associate with LXXLL motifs on target cellular proteins to alter their function. Using a proteomic approach, we found the E6 oncoproteins of cutaneous papillomaviruses Bovine Papillomavirus Type 1 (BE6) and HPV types 1 and 8 (1E6 and 8E6) associated with the MAML1 transcriptional co-activator. All three E6 proteins bind to an acidic LXXLL motif at the carboxy-terminus of MAML1 and repress transactivation by MAML1. MAML1 is best known as the co-activator and effector of NOTCH induced transcription, and BPV-1 E6 represses synthetic NOTCH responsive promoters, endogenous NOTCH responsive promoters, and is found in a complex with MAML1 in stably transformed cells. BPV-1 induced papillomas show characteristics of repressed NOTCH signal transduction, including suprabasal expression of integrins, talin, and basal type keratins, and delayed expression of the NOTCH dependent HES1 transcription factor. These observations give rise to a model whereby papillomavirus oncoproteins including BPV-1 E6 and the cancer associated HPV-8 E6 repress Notch induced transcription, thereby delaying keratinocyte differentiation.

Brimer, Nicole; Lyons, Charles; Wallberg, Annika E.; Vande Pol, Scott B.

2011-01-01

124

Cutaneous papillomavirus E6 oncoproteins associate with MAML1 to repress transactivation and NOTCH signaling.  

PubMed

Papillomavirus E6 oncoproteins associate with LXXLL motifs on target cellular proteins to alter their function. Using a proteomic approach, we found the E6 oncoproteins of cutaneous papillomaviruses Bovine Papillomavirus Type 1 (BPV-1) E6 and human papillomavirus (HPV) types 1 and 8 (1E6 and 8E6) associated with the MAML1 transcriptional co-activator. All three E6 proteins bind to an acidic LXXLL motif at the carboxy-terminus of MAML1 and repress transactivation by MAML1. MAML1 is best known as the co-activator and effector of NOTCH-induced transcription, and BPV-1 E6 represses synthetic NOTCH-responsive promoters, endogenous NOTCH-responsive promoters, and is found in a complex with MAML1 in stably transformed cells. BPV-1-induced papillomas show characteristics of repressed NOTCH signal transduction, including suprabasal expression of integrins, talin and basal type keratins, and delayed expression of the NOTCH-dependent HES1 transcription factor. These observations give rise to a model whereby papillomavirus oncoproteins, including BPV-1 E6, and the cancer-associated HPV-8 E6 repress NOTCH-induced transcription, thereby delaying keratinocyte differentiation. PMID:22249263

Brimer, N; Lyons, C; Wallberg, A E; Vande Pol, S B

2012-01-16

125

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

2012-12-04

126

Serum growth factors and oncoproteins in firefighters.  

PubMed

Firefighters are potentially at increased risk for cancer and non-malignant respiratory disease due to their toxic exposures on the job. Growth factors and oncogene proteins are thought to play a role in the development of various malignancies and pulmonary fibrotic diseases. Therefore, a cohort of firefighters and matched controls have been screened for the presence of nine different growth factors and oncoproteins using an immunoblotting assay. Fourteen of the firefighters were found to be positive for beta-transforming growth factor (beta-TGF) related proteins compared to no positives in the controls (P = 0.0017). These results suggest that beta-TGF may be a possible biomarker for monitoring firefighters and other exposed workers for the potential development of cancer or non-malignant respiratory disease. PMID:1533320

Ford, J; Smith, S; Luo, J C; Friedman-Jimenez, G; Brandt-Rauf, P; Markowitz, S; Garibaldi, K; Niman, H

1992-02-01

127

Systematic Analysis of the Amino Acid Residues of Human Papillomavirus Type 16 E7 Conserved Region 3 Involved in Dimerization and Transformation ?  

PubMed Central

The human papillomavirus (HPV) E7 oncoprotein exists as a dimer and acts by binding to many cellular factors, preventing or retargeting their function and thereby making the infected cell conducive for viral replication. Dimerization of E7 is attributed primarily to the C-terminal domain, referred to as conserved region 3 (CR3). CR3 is highly structured and is necessary for E7's transformation ability. It is also required for binding of numerous E7 cellular targets. To systematically analyze the molecular mechanisms by which HPV16 E7 CR3 contributes to carcinogenesis, we created a comprehensive panel of mutations in residues predicted to be exposed on the surface of CR3. We analyzed our novel collection of mutants, as well as mutants targeting predicted hydrophobic core residues of the dimer, for the ability to dimerize. The same set of mutants was also assessed functionally for transformation capability in a baby rat kidney cell assay in conjugation with activated ras. We show that some mutants of HPV16 E7 CR3 failed to dimerize yet were still able to transform baby rat kidney cells. Our results identify several novel E7 mutants that abrogate transformation and also indicate that E7 does not need to exist as a stable dimer in order to transform cells.

Todorovic, Biljana; Massimi, Paola; Hung, Katherine; Shaw, Gary S.; Banks, Lawrence; Mymryk, Joe S.

2011-01-01

128

Structural Studies of the pRB Tumor Suppressor Complexed with Human Papillomavirus E7 Proteins.  

National Technical Information Service (NTIS)

Since viral oncoproteins are expected to compete with and imitate interactions that pRB has with cyclin DI, understanding high affinity pRB-viral oncoprotein complexes will provide tremendous insight into the specific interactions required for the develop...

A. M. Cements

1999-01-01

129

Structural Studies of the pRB Tumor Suppressor Complexed with Human Papillomavirus E7 Proteins.  

National Technical Information Service (NTIS)

Since viral oncoproteins are expected to compete with and imitate interactions that pRB has with cyclin Dl, understanding high affinity pRB-viral oncoprotein complexes will provide tremendous insight into the specific interactions required for the develop...

A. Clements

2000-01-01

130

Cooperative Interactions of HER-2 and HPV-16 Oncoproteins in the Malignant Transformation of Human Mammary Epithelial Cells1  

PubMed Central

Abstract To better understand the mechanisms of transformation by the oncogene HER-2, we transduced the human mammary epithelial (HME) cell line MCF-10A with HER-2 and developed a cell line that appeared to moderately overexpress HER-2. These MCF-10HER-2 cells were unable to grow in the absence of epidermal growth factor (EGF). However, coexpression of HER-2 with the HPV-16 oncoproteins E6 and E7 resulted in EGF-independent cells that expressed very high levels of constitutively activated HER-2. Interestingly, coexpression of E7 with HER-2 resulted in cells that were EGF-independent for growth but did not express HER-2 to high levels, and coexpression of E6 with HER-2 resulted in cells expressing higher levels of HER-2, which were still dependent on EGF for growth and survival. The MCF-10HER-2E7 and HER-2/E6E7 cells exhibited constitutive activation of a form of epidermal growth factor receptor (EGFR) that had a faster electrophoretic mobility than EGFR activated by exogenous growth factors. Exposure of cells with EGFR activation to ZD1839 (Iressa), at concentrations specific for EGFR, had little or no influence on proliferation of cells with amplified HER-2 but little or no EGFR. These results indicate that HER-2, E6, and E7 cooperate with endogenous EGFR to yield fully transformed cells.

Woods Ignatoski, Kathleen M; Dziubinski, Michele L; Ammerman, Cheryl; Ethier, Stephen P

2005-01-01

131

Activation of human papillomavirus type 18 E6-E7 oncogene expression by transcription factor Sp1.  

PubMed Central

The human papillomavirus 18 (HPV18) E6 and E7 proteins are considered to be primarily responsive for the transforming activity of the virus. In order to analyse the molecular mechanisms resulting in viral oncoprotein expression, it is necessary to identify the factors involved in the transcriptional regulation of the E6/E7 genes. Here we define by gel retardation experiments a sequence aberrant Sp1 binding site present in the promoter proximal part of the viral transcriptional control region (Upstream Regulatory Region, URR). Functional analyses employing transient reporter assays reveal that this Sp1 element is required for an efficient stimulation of the HPV18 E6/E7-promoter. Mutation of the Sp1 element in the natural context of the HPV18 URR leads to a strong decrease in the activity of the E6/E7-promoter in several cell lines. The magnitude of reduction varies between different cell types and is higher in cell lines of epithelial origin when compared with nonepithelial cells. Cotransfection assays using Sp1 expression vector systems further define the promoter proximal HPV18 Sp1 binding motif as a functional Sp1 element in vivo and show that its integrity is essential for the stimulation of the E6/E7-promoter by augmented levels of Sp1. These results indicate, that the cellular transcription factor Sp1 plays an important role for the stimulation of the E6/E7-promoter by the viral URR and represents a major determinant for the expression of HPV18 transforming genes E6 and E7. Images

Hoppe-Seyler, F; Butz, K

1992-01-01

132

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.

Boon, Siaw Shi

2013-01-01

133

A Molecular Model for the Differential Activation of STAT3 and STAT6 by the Herpesviral Oncoprotein Tip  

PubMed Central

Constitutive STAT signaling provides growth promoting signals in many forms of malignancy. We performed molecular modeling and molecular dynamics studies of the interaction between the regulatory Src homology 2 (SH2) domains of STAT3 and 6 with phosphorylated peptides of the herpesviral oncoprotein Tip, which facilitates Src kinase mediated STAT-activation and T cell proliferation. The studies give insight into the ligand binding specificity of the STAT SH2 domains and provide the first model for the differential activation of STAT3 or STAT6 by two distinct regions of the viral Tip protein. The biological relevance of the modeled interactions was then confirmed by activation studies using corresponding recombinant oncoproteins, and finally by respective recombinant viruses. The functional data give experimental validation of the molecular dynamics study, and provide evidence for the involvement of STAT6 in the herpesvirus induced T cell proliferation.

Vogel, Benjamin; Heck, Elke; Scholz, Brigitte; Lengenfelder, Doris; Sticht, Heinrich; Ensser, Armin

2012-01-01

134

EWS–ETS oncoproteins: The linchpins of Ewing tumors  

Microsoft Academic Search

Ewing tumors, which comprise Ewing's sarcoma and peripheral primitive neuroectodermal tumors, are highly aggressive and mostly affect children and adolescents. Their molecular signature is a chromosomal translocation leading to the generation of EWS–ETS (or very rarely FUS–ETS) fusion proteins that are capable of transforming cells. These oncoproteins act as aberrant transcription factors due to the fusion of an ETS DNA

Ralf Janknecht

2005-01-01

135

New Approach to Identify Novel Regulators of Myc Oncoprotein Stability.  

National Technical Information Service (NTIS)

The Myc oncoprotein is deregulated in the majority of breast cancers yet it has not been possible to develop a therapeutic to target Myc using traditional approaches. It has recently been shown that targeting Myc for degradation may offer a new therapeuti...

L. Z. Penn

2012-01-01

136

Degradation of nuclear oncoproteins by the ubiquitin system in vitro  

SciTech Connect

Nuclear oncoproteins are among the most rapidly degraded intracellular proteins. Previous work has implicated the ubiquitin-mediated proteolytic system in the turnover of short-lived intracellular proteins. In the present study, the authors have evaluated the potential role of the ubiquitin system in the degradation of the specific nuclear oncoproteins encoded by the N-myc, c-myc, c-fos, p53, and E1A genes. Each of these nuclear oncoproteins was synthesized in vitro by transcription of the appropriate cDNA and translation of the resulting mRNA in the presence of ({sup 35}S)methionine. Degradation of labeled proteins was monitored in the ubiquitin cell-free system. ATP stimulated the degradation of all the proteins between 3- and 10-fold. The degradation was completely inhibited by neutralizing antibody directed against the ubiquitin-activating enzyme, E{sub 1}, the first enzyme in the ubiquitin-mediated proteolytic cascade. Morever, degradation in E{sub 1}-depleted lysates could be restored in each case by the addition of affinity-purified E{sub 1}. These data suggest that the ubiquitin system mediates the degradation of these oncoproteins in vitro. Degradation of other proteins, such as superoxide dismutase, cytochrome c, enolase, RNase A, and ornithine decarboxylase, is not mediated by the ubiquitin cell-free system. This suggests that the nuclear oncoproteins studies here possess specific signals that target them for rapid turnover by this proteolytic pathway. Furthermore, the relative sensitivity to degradation of various E1A mutants in vivo is also maintained in the cell-free system, suggesting that the ubiquitin pathway may play a role in the cellular degradation of these proteins as well.

Ciechanover, A.; Bercovich, B.; Orian, A. (Technion-Israel Inst. of Tech., Haifa (Israel)); DiGiuseppe, J.A.; Schwartz, A.L.; Brodeur, G.M. (Washington Univ. School of Medicine, St. Louis, MO (United States)); Richter, J.D. (Worcester Foundation for Experimental Biology, Shrewsbury, MA (United States))

1991-01-01

137

Polycation-? Interactions Are a Driving Force for Molecular Recognition by an Intrinsically Disordered Oncoprotein Family.  

PubMed

Molecular recognition by intrinsically disordered proteins (IDPs) commonly involves specific localized contacts and target-induced disorder to order transitions. However, some IDPs remain disordered in the bound state, a phenomenon coined "fuzziness", often characterized by IDP polyvalency, sequence-insensitivity and a dynamic ensemble of disordered bound-state conformations. Besides the above general features, specific biophysical models for fuzzy interactions are mostly lacking. The transcriptional activation domain of the Ewing's Sarcoma oncoprotein family (EAD) is an IDP that exhibits many features of fuzziness, with multiple EAD aromatic side chains driving molecular recognition. Considering the prevalent role of cation-? interactions at various protein-protein interfaces, we hypothesized that EAD-target binding involves polycation- ? contacts between a disordered EAD and basic residues on the target. Herein we evaluated the polycation-? hypothesis via functional and theoretical interrogation of EAD variants. The experimental effects of a range of EAD sequence variations, including aromatic number, aromatic density and charge perturbations, all support the cation-? model. Moreover, the activity trends observed are well captured by a coarse-grained EAD chain model and a corresponding analytical model based on interaction between EAD aromatics and surface cations of a generic globular target. EAD-target binding, in the context of pathological Ewing's Sarcoma oncoproteins, is thus seen to be driven by a balance between EAD conformational entropy and favorable EAD-target cation-? contacts. Such a highly versatile mode of molecular recognition offers a general conceptual framework for promiscuous target recognition by polyvalent IDPs. PMID:24086122

Song, Jianhui; Ng, Sheung Chun; Tompa, Peter; Lee, Kevin A W; Chan, Hue Sun

2013-09-26

138

Polycation-? Interactions Are a Driving Force for Molecular Recognition by an Intrinsically Disordered Oncoprotein Family  

PubMed Central

Molecular recognition by intrinsically disordered proteins (IDPs) commonly involves specific localized contacts and target-induced disorder to order transitions. However, some IDPs remain disordered in the bound state, a phenomenon coined “fuzziness”, often characterized by IDP polyvalency, sequence-insensitivity and a dynamic ensemble of disordered bound-state conformations. Besides the above general features, specific biophysical models for fuzzy interactions are mostly lacking. The transcriptional activation domain of the Ewing's Sarcoma oncoprotein family (EAD) is an IDP that exhibits many features of fuzziness, with multiple EAD aromatic side chains driving molecular recognition. Considering the prevalent role of cation-? interactions at various protein-protein interfaces, we hypothesized that EAD-target binding involves polycation- ? contacts between a disordered EAD and basic residues on the target. Herein we evaluated the polycation-? hypothesis via functional and theoretical interrogation of EAD variants. The experimental effects of a range of EAD sequence variations, including aromatic number, aromatic density and charge perturbations, all support the cation-? model. Moreover, the activity trends observed are well captured by a coarse-grained EAD chain model and a corresponding analytical model based on interaction between EAD aromatics and surface cations of a generic globular target. EAD-target binding, in the context of pathological Ewing's Sarcoma oncoproteins, is thus seen to be driven by a balance between EAD conformational entropy and favorable EAD-target cation-? contacts. Such a highly versatile mode of molecular recognition offers a general conceptual framework for promiscuous target recognition by polyvalent IDPs.

Tompa, Peter; Lee, Kevin A. W.; Chan, Hue Sun

2013-01-01

139

Induction of p21WAF1\\/CIP1 and cyclin D1 expression by the Src oncoprotein in mouse fibroblasts: role of activated STAT3 signaling  

Microsoft Academic Search

While the activated viral Src oncoprotein, v-Src, induces uncontrolled cell growth, the mechanisms underlying cell cycle deregulation by v-Src have not been fully defined. Previous studies demonstrated that v-Src induces constitutively active STAT3 signaling that is required for cell transformation and recent data have implicated STAT3 in the transcriptional control of critical cell cycle regulators. Here we show in mouse

Dominic Sinibaldi; Walker Wharton; James Turkson; Tammy Bowman; Warren J Pledger; Richard Jove

2000-01-01

140

Predicted alpha-helix/beta-sheet secondary structures for the zinc-binding motifs of human papillomavirus E7 and E6 proteins by consensus prediction averaging and spectroscopic studies of E7.  

PubMed Central

The E7 and E6 proteins are the main oncoproteins of human papillomavirus types 16 and 18 (HPV-16 and HPV-18), and possess unknown protein structures. E7 interacts with the cellular tumour-suppressor protein pRB and contains a zinc-binding site with two Cys-Xaa2-Cys motifs spaced 29 or 30 residues apart. E6 interacts with another cellular tumour-suppressor protein p53 and contains two zinc-binding sites, each with two Cys-Xaa2-Cys motifs at a similar spacing of 29 or 30 residues. By using the GOR I/III, Chou-Fasman, SAPIENS and PHD methods, the effectiveness of consensus secondary structure predictions on zinc-finger proteins was first tested with sequences for 160 transcription factors and 72 nuclear hormone receptors. These contain Cys2His2 and Cys2Cys2 zinc-binding regions respectively, and possess known atomic structures. Despite the zinc- and DNA-binding properties of these protein folds, the major alpha-helix structures in both zinc-binding regions were correctly identified. Thus validated, the use of these prediction methods with 47 E7 sequences indicated four well-defined alpha-helix (alpha) and beta-sheet (beta) secondary structure elements in the order beta beta alpha beta in the zinc-binding region of E7 at its C-terminus. The prediction was tested by Fourier transform infrared spectroscopy of recombinant HPV-16 E7 in H2O and 2H2O buffers. Quantitative integration showed that E7 contained similar amounts of alpha-helix and beta-sheet structures, in good agreement with the averaged prediction of alpha-helix and beta-sheet structures in E7 and also with previous circular dichroism studies. Protein fold recognition analyses predicted that the structure of the zinc-binding region in E7 was similar to a beta beta alpha beta motif found in the structure of Protein G. This is consistent with the E7 structure predictions, despite the low sequence similarities with E7. This predicted motif is able to position four Cys residues in proximity to a zinc atom. A model for the zinc-binding motif of E7 was constructed by combining the Protein G coordinates with those for the zinc-binding site in transcription factor TFIIS. Similar analyses for the two zinc-binding motifs in E6 showed that they have different alpha/beta secondary structures from that in E7. When compared with 12 other zinc-binding proteins, these results show that E7 and E6 are predicted to possess novel types of zinc-binding structure.

Ullman, C G; Haris, P I; Galloway, D A; Emery, V C; Perkins, S J

1996-01-01

141

EWS-ETS oncoproteins: the linchpins of Ewing tumors.  

PubMed

Ewing tumors, which comprise Ewing's sarcoma and peripheral primitive neuroectodermal tumors, are highly aggressive and mostly affect children and adolescents. Their molecular signature is a chromosomal translocation leading to the generation of EWS-ETS (or very rarely FUS-ETS) fusion proteins that are capable of transforming cells. These oncoproteins act as aberrant transcription factors due to the fusion of an ETS DNA binding domain to a highly potent EWS (or FUS) transactivation domain. Accordingly, many EWS-ETS target genes have been identified whose dysregulation could contribute to the development of tumor formation. Furthermore, EWS-ETS oncoproteins may impact on RNA splicing or affect other proteins through disturbing their ability to form functional complexes. The molecular knowledge gained so far from studying EWS-ETS oncoproteins has not only broadened our understanding of Ewing tumors but also improved the diagnosis of these highly undifferentiated tumors. In addition, several potential prognostic markers have been uncovered and novel therapies are suggested that may improve the still dismal survival rate of Ewing tumor patients. PMID:16202544

Janknecht, Ralf

2005-10-03

142

Interaction of HPV E6 oncoproteins with specific proteasomal subunits.  

PubMed

The Human Papillomavirus E6 oncoproteins have the capacity to target several of their cellular interacting partners for proteasome mediated degradation, and recent proteomic analyses suggest a close involvement of E6 with the cellular proteasome machinery. In this study we have performed an extensive analysis of the capacity of different E6 oncoproteins to interact with specific proteasome components. We demonstrate that multiple subunits of the proteasome can be bound by different HPV E6 oncoproteins. Furthermore, whilst most of these interactions appear independent of the E6AP ubiquitin ligase, the association of E6 with the major ubiquitin-accepting proteasome subunit, S5a, does require the presence of E6AP. One consequence of the interaction between E6/E6AP and S5a is enhanced ubiquitination of this proteasome subunit. These results suggest a complex interplay between E6 and the proteasome, only some aspects of which are dependent upon the E6AP ubiquitin ligase. PMID:24074603

Tomai?, Vjekoslav; Ganti, Ketaki; Pim, David; Bauer, Christina; Blattner, Christine; Banks, Lawrence

2013-09-17

143

Structural Studies of the pRB Tumor Suppressor Complexed with Human Papillomavirus E7.  

National Technical Information Service (NTIS)

Since viral oncoproteins are expected to compete with and imitate interactions that pRB has with cyclin D1, understanding high affinity pRB-viral oncoprotein complexes will provide tremendous insight into the specific interactions required for the develop...

A. M. Clements

1998-01-01

144

Intrinsic ubiquitination activity of PCAF controls the stability of the oncoprotein Hdm2.  

PubMed

The p300-CBP-associated factor (PCAF) is a histone acetyltransferase (HAT) involved in the reversible acetylation of various transcriptional regulators, including the tumour suppressor p53. It is implicated in many cellular processes, such as transcription, differentiation, proliferation and apoptosis. We observed that knockdown of PCAF expression in HeLa or U2OS cell lines induces stabilization of the oncoprotein Hdm2, a RING finger E3 ligase primarily known for its role in controlling p53 stability. To investigate the molecular basis of this effect, we examined whether PCAF is involved in Hdm2 ubiquitination. Here, we show that PCAF, in addition to its acetyltransferase activity, possesses an intrinsic ubiquitination activity that is critical for controlling Hdm2 expression levels, and thus p53 functions. Our data highlight a regulatory crosstalk between PCAF and Hdm2 activities, which is likely to have a central role in the subtle control of p53 activity after DNA damage. PMID:17293853

Linares, Laëtitia K; Kiernan, Rosemary; Triboulet, Robinson; Chable-Bessia, Christine; Latreille, Daniel; Cuvier, Olivier; Lacroix, Matthieu; Le Cam, Laurent; Coux, Olivier; Benkirane, Monsef

2007-02-11

145

A Humanized Mouse Model of HPV-Associated Pathology Driven by E7 Expression  

PubMed Central

Human papillomavirus (HPV) is the causative agent of human cervical cancer and has been associated with oropharyngeal squamous cell carcinoma development. Although prophylactic vaccines have been developed, there is a need to develop new targeted therapies for individuals affected with malignant infected lesions in these locations, which must be tested in appropriate models. Cutaneous beta HPV types appear to be involved in skin carcinogenesis. Virus oncogenicity is partly achieved by inactivation of retinoblastoma protein family members by the viral E7 gene. Here we show that the E7 protein of cutaneous beta HPV5 binds pRb and promotes its degradation. In addition, we described an in vivo model of HPV-associated disease in which artificial human skin prepared using primary keratinocytes engineered to express the E7 protein is engrafted onto nude mice. Expression of E7 in the transplants was stably maintained for up to 6 months, inducing the appearance of lesions that, in the case of HPV16 E7, histologically resembled human anogenital lesions caused by oncogenic HPVs. Moreover, it was confirmed through biomarker expression analysis via immunodetection and/or quantitative PCR from mRNA and miRNA that the 16E7-modified engrafted skin shares molecular features with human HPV-associated pretumoral and tumoral lesions. Finally, our findings indicate a decrease of the in vitro capacity of HPV5 E7 to reduce pRb levels in vivo, possibly explaining the phenotypical differences when compared with 16E7-grafts. Our model seems to be a valuable platform for basic research into HPV oncogenesis and preclinical testing of HPV-associated antitumor therapies.

Buitrago-Perez, Agueda; Hachimi, Mariam; Duenas, Marta; Lloveras, Belen; Santos, Almudena; Holguin, Almudena; Duarte, Blanca; Santiago, Juan Luis; Akgul, Baki; Rodriguez-Peralto, Jose L.; Storey, Alan; Ribas, Catalina; Larcher, Fernando; del Rio, Marcela; Paramio, Jesus M.; Garcia-Escudero, Ramon

2012-01-01

146

Modulation of oxidative stress by twist oncoproteins.  

PubMed

Expression of developmental genes Twist1 and Twist2 is reactivated in many human tumors. Among their oncogenic activities, induction of epithelial to mesenchymal transition is believed to increase cell motility and invasiveness and may be related to acquisition of cancer stem cell phenotype. In addition, Twist proteins promote malignant conversion by overriding two oncogene-induced failsafe programs: senescence and apoptosis. Reactive oxygen species (ROS) are also important mediators of apoptosis, senescence and motility and are tightly linked to disease, notably to cancer. We report here that Twist factors and ROS are functionally linked. In wild type cells both Twist1 and Twist2 exhibit antioxidant properties. We show that Twist-driven modulation of oncogene-induced apoptosis is linked to its effects on oxidative stress. Finally, we identify several targets that mediate Twist antioxidant activity. These findings unveil a new function of Twist factors that could be important in explaining their pleiotropic role during carcinogenesis. PMID:23967308

Floc'h, Nicolas; Kolodziejski, Jakub; Akkari, Leila; Simonin, Yannick; Ansieau, Stéphane; Puisieux, Alain; Hibner, Urszula; Lassus, Patrice

2013-08-13

147

Fowlpox virus recombinants expressing HPV-16 E6 and E7 oncogenes for the therapy of cervical carcinoma elicit humoral and cell-mediated responses in rabbits  

PubMed Central

Background Around half million new cases of cervical cancer arise each year, making the development of an effective therapeutic vaccine against HPV a high priority. As the E6 and E7 oncoproteins are expressed in all HPV-16 tumour cells, vaccines expressing these proteins might clear an already established tumour and support the treatment of HPV-related precancerous lesions. Methods Three different immunisation regimens were tested in a pre-clinical trial in rabbits to evaluate the humoral and cell-mediated responses of a putative HPV-16 vaccine. Fowlpoxvirus (FP) recombinants separately expressing the HPV-16 E6 (FPE6) and E7 (FPE7) transgenes were used for priming, followed by E7 protein boosting. Results All of the protocols were effective in eliciting a high antibody response. This was also confirmed by interleukin-4 production, which increased after simultaneous priming with both FPE6 and FPE7 and after E7 protein boost. A cell-mediated immune response was also detected in most of the animals. Conclusion These results establish a preliminary profile for the therapy with the combined use of avipox recombinants, which may represent safer immunogens than vaccinia-based vectors in immuno-compromised individuals, as they express the transgenes in most mammalian cells in the absence of a productive replication.

2010-01-01

148

A conserved E7-derived cytotoxic T lymphocyte epitope expressed on human papillomavirus 16-transformed HLA-A2+ epithelial cancers.  

PubMed

Human Papillomavirus 16 (HPV-16) has been identified as the causative agent of 50% of cervical cancers and many other HPV-associated tumors. The transforming potential/tumor maintenance capacity of this high risk HPV is mediated by two viral oncoproteins, E6 and E7, making them attractive targets for therapeutic vaccines. Of 21 E6 and E7 peptides computed to bind HLA-A*0201, 10 were confirmed through TAP-deficient T2 cell HLA stabilization assay. Those scoring positive were investigated to ascertain which were naturally processed and presented by surface HLA molecules for CTL recognition. Because IFN? ELISpot frequencies from healthy HPV-exposed blood donors against HLA-A*0201-binding peptides were unable to identify specificities for tumor targeting, their physical presence among peptides eluted from HPV-16-transformed epithelial tumor HLA-A*0201 immunoprecipitates was analyzed by MS(3) Poisson detection mass spectrometry. Only one epitope (E7(11-19)) highly conserved among HPV-16 strains was detected. This 9-mer serves to direct cytolysis by T cell lines, whereas a related 10-mer (E7(11-20)), previously used as a vaccine candidate, was neither detected by MS(3) on HPV-transformed tumor cells nor effectively recognized by 9-mer specific CTL. These data underscore the importance of precisely defining CTL epitopes on tumor cells and offer a paradigm for T cell-based vaccine design. PMID:20615877

Riemer, Angelika B; Keskin, Derin B; Zhang, Guanglan; Handley, Maris; Anderson, Karen S; Brusic, Vladimir; Reinhold, Bruce; Reinherz, Ellis L

2010-07-08

149

Characterization of Physical Binding between Human Papillomavirus 18 Protein E7 and Centromere Protein C  

Microsoft Academic Search

Human papillomaviruses (HPVs) have been linked to a variety of human diseases, most notably cancer of the cervix. In the majority of cases, HPV proteins E6 and E7 are continuously expressed and bind a variety of cellular proteins. The precise mechanism of HPV-induced carcinogenesis has not been fully elucidated; therefore, we attempted to identify the cellular proteins that interact with

Yuji Yaginuma; Kinya Yoda; Katsuhiro Ogawa

2010-01-01

150

Curcumin counteracts the proliferative effect of estradiol and induces apoptosis in cervical cancer cells  

Microsoft Academic Search

Cervical cancer is the most common cancer in Indian females and is associated with infection with high-risk Human papilloma\\u000a viruses (HPVs) which encode viral oncoprotein E6 and E7. Estradiol has been established as a risk factor for cervical cancer\\u000a and has been shown to play a synergistic role with viral oncoproteins. Curcumin (Diferuloyl methane), a chemopreventive agent,\\u000a is a natural

Mayank SinghNeeta Singh; Neeta Singh

2011-01-01

151

Modeling and molecular dynamics of the intrinsically disordered e7 proteins from high- and low-risk types of human papillomavirus.  

PubMed

Cervical cancer affects millions of women worldwide each year. Most cases of cervical cancer are caused by the sexually transmitted human papillomavirus (HPV). The approximately 40 HPV types that infect the cervix are designated high- or low-risk based on their potential to lead to high-grade lesions and cancer. The HPV E7 oncoprotein is directly involved in the onset of cervical cancer and associates with the pRb protein and other cellular targets that promote cell immortalization and carcinogenesis. This is the first description of the modeling and molecular dynamics analysis of complete three-dimensional structures of high-risk (HPV types 16 and 18), low-risk (HPV type 11), and HPV type 01 E7 proteins. The models were constructed by a hybrid approach using homology (MODELLER) and ab initio (Rosetta) modeling, and the protein dynamics were simulated for 50 ns under normal pressure and temperature (NPT) conditions. The intrinsic disorder of the E7 protein sequence was assessed in silico. Complete models of E7 were obtained despite the predicted intrinsic disorder of the N-termini from the high-risk HPV types. The N-terminal domains of all of the E7 proteins studied, even those from high-risk strains, exhibited secondary structure after modeling. Trajectory analysis of E7 proteins from HPV types 16 and 18 showed higher instability in their N-terminal domains than in those of HPV types 11 and 01; however, this variation did not affect the secondary structure during the simulation. ANCHOR analysis indicated that the CR1 and CR2 regions of HPV types 16 and 18 contain possible targets for future drug-discovery studies. PMID:23864166

Nicolau-Junior, Nilson; Giuliatti, Silvana

2013-07-18

152

Boosting with recombinant vaccinia increases HPV16 E7-specific T cell precursor frequencies of HPV16 E7-expressing DNA vaccines  

Microsoft Academic Search

We have previously linked the sorting signals of the lysosome-associated membrane protein-1 (LAMP-1) to HPV-16 E7 antigen, creating a chimera, Sig\\/E7\\/LAMP-1. We found that both Sig\\/E7\\/LAMP-1-containing recombinant vaccinia virus (Vac–Sig\\/E7\\/LAMP-1) and Sig\\/E7\\/LAMP-1 DNA can generate strong antitumor immunity. To determine whether combination of Sig\\/E7\\/LAMP-1 DNA and Vac–Sig\\/E7\\/LAMP-1 can further enhance immune responses, sequential vaccination with Sig\\/E7\\/LAMP-1 DNA and Vac–Sig\\/E7\\/LAMP-1 was

Chien-Hung Chen; Tian-Li Wang; Chien.-Fu Hung; Drew M Pardoll; T.-C Wu

2000-01-01

153

The Sumo-targeted ubiquitin ligase RNF4 regulates the localization and function of the HTLV-1 oncoprotein Tax.  

PubMed

The Really Interesting New Gene (RING) Finger Protein 4 (RNF4) represents a class of ubiquitin ligases that target Small Ubiquitin-like Modifier (SUMO)-modified proteins for ubiquitin modification. To date, the regulatory function of RNF4 appears to be ubiquitin-mediated degradation of sumoylated cellular proteins. In the present study, we show that the Human T-cell Leukemia Virus Type 1 (HTLV-1) oncoprotein Tax is a substrate for RNF4 both in vivo and in vitro. We mapped the RNF4-binding site to a region adjacent to the Tax ubiquitin/SUMO modification sites K280/K284. Interestingly, RNF4 modification of Tax protein results in relocalization of the oncoprotein from the nucleus to the cytoplasm. Overexpression of RNF4, but not the RNF4 RING mutant, resulted in cytoplasmic enrichment of Tax. The RNF4-induced nucleus-to-cytoplasm relocalization was associated with increased NF-?B-mediated and decreased cAMP Response Element-Binding (CREB)-mediated Tax activity. Finally, depletion of RNF4 by RNAi prevented the DNA damage-induced nuclear/cytoplasmic translocation of Tax. These results provide important new insight into STUbL-mediated pathways that regulate the subcellular localization and functional dynamics of viral oncogenes. PMID:22106342

Fryrear, Kimberly A; Guo, Xin; Kerscher, Oliver; Semmes, O John

2011-11-21

154

Human papillomavirus E6 and E7 oncoproteins alter cell cycle progression but not radiosensitivity of carcinoma cells treated with low-dose-rate radiation  

Microsoft Academic Search

Purpose: Low-dose-rate radiation therapy has been widely used in the treatment of urogenital malignancies. When continuously exposed to low-dose-rate ionizing radiation, target cancer cells typically exhibit abnormalities in replicative cell-cycle progression. Cancer cells that arrest in the G2 phase of the cell cycle when irradiated may become exquisitely sensitive to killing by further low-dose-rate radiation treatment. Oncogenic human papillomaviruses (HPVs),

Theodore L. DeWeese; Jonathan C. Walsh; Larry E. Dillehay; Theodore D. Kessis; Lora Hedrick; Kathleen R. Cho; William G. Nelson

1997-01-01

155

The lethal giant larvae tumour suppressor mutation requires dMyc oncoprotein to promote clonal malignancy  

PubMed Central

Background Neoplastic overgrowth depends on the cooperation of several mutations ultimately leading to major rearrangements in cellular behaviour. Precancerous cells are often removed by cell death from normal tissues in the early steps of the tumourigenic process, but the molecules responsible for such a fundamental safeguard process remain in part elusive. With the aim to investigate the molecular crosstalk occurring between precancerous and normal cells in vivo, we took advantage of the clonal analysis methods that are available in Drosophila for studying the phenotypes due to lethal giant larvae (lgl) neoplastic mutation induced in different backgrounds and tissues. Results We observed that lgl mutant cells growing in wild-type imaginal wing discs show poor viability and are eliminated by Jun N-terminal Kinase (JNK)-dependent cell death. Furthermore, they express very low levels of dMyc oncoprotein compared with those found in the surrounding normal tissue. Evidence that this is a cause of lgl mutant cells elimination was obtained by increasing dMyc levels in lgl mutant clones: their overgrowth potential was indeed re-established, with mutant cells overwhelming the neighbouring tissue and forming tumourous masses displaying several cancer hallmarks. Moreover, when lgl mutant clones were induced in backgrounds of slow-dividing cells, they upregulated dMyc, lost apical-basal cell polarity and were able to overgrow. Those phenotypes were abolished by reducing dMyc levels in the mutant clones, thereby confirming its key role in lgl-induced tumourigenesis. Furthermore, we show that the eiger-dependent Intrinsic Tumour Suppressor pathway plays only a minor role in eliminating lgl mutant cells in the wing pouch; lgl-/- clonal death in this region is instead driven mainly by dMyc-induced Cell Competition. Conclusions Our results provide the first evidence that dMyc oncoprotein is required in lgl tumour suppressor mutant tissue to promote invasive overgrowth in larval and adult epithelial tissues. Moreover, we show that dMyc abundance inside versus outside the mutant clones plays a key role in driving neoplastic overgrowth.

2010-01-01

156

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.

Gonzalez-Cintado, Leticia; Kowalczyk, Wioleta; Jimenez Torres, Ignacio; Calderita, Gloria; Rodriguez, Margarita; Gondar, Virginia; Bernal, Juan Jose; Ardavin, Carlos; Andreu, David; Zurcher, Thomas; von Kobbe, Cayetano

2012-01-01

157

Chimeric infectious bursal disease virus-like particles as potent vaccines for eradication of established HPV-16 E7-dependent tumors.  

PubMed

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

Martin Caballero, Juan; Garzón, Ana; 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

2012-12-31

158

Concomitant Oncoprotein Detection with Fluorescence in Situ Hybridization (CODFISH)  

PubMed Central

We sought the validation of a three-color fluorescence-based system that simultaneously profiles Her-2/neu oncogene copy by fluorescence in situ hybridization (FISH) and Her-2/neu encoded protein by the use of a versatile alkaline phosphatase chromogen fast red K in either fluorescence or bright-field mode. Nuclei were counterstained with DAPI. Nineteen infiltrating ductal carcinomas of breast were comprehensively evaluated for Her-2/neu amplification/overexpression by direct and indirect FISH using digoxigenin (DigFISH) and direct fluorescently labeled probes, autoradiographic RNA:RNA in situ hybridization, and immunohistochemistry using monoclonal antibody CB11. CODFISH results correlated well with DigFISH, direct-label FISH, mRNA expression, and oncoprotein expression as assessed with CB11, and enabled simultaneous visualization of gene copy and protein. In addition, qualitative immunohistochemistry may be followed by CODFISH gene copy enumeration to clarify ambiguous cases.

Tubbs, Raymond R.; Pettay, James; Roche, Pat; Stoler, Mark H.; Jenkins, Robert; Myles, Jon; Grogan, Thomas

2000-01-01

159

An improved rearranged Human Papillomavirus Type 16 E7 DNA vaccine candidate (HPV16 E7SH) induces an E7 wildtype-specific T cell response  

Microsoft Academic Search

A new and very promising approach in vaccine development is the application of naked DNA. In comparison to conventional vaccines it offers several advantages, especially if there is a need for the development of low cost vaccines. Infection with high-risk human papillomaviruses (hr-HPVs) is the major risk factor for the development of cervical cancer (cc), the third most common cancer

Peter Öhlschläger; Michaela Pes; Wolfram Osen; Matthias Dürst; Achim Schneider; Lutz Gissmann; Andreas M. Kaufmann

2006-01-01

160

New E 7(7) invariants and amplitudes  

NASA Astrophysics Data System (ADS)

We construct a new class of manifest E 7(7) duality invariants, which generalize the Cartan quartic invariant, familiar from studies of the black hole entropy. The new ones, being four-linear, are designed for studies of the four-vector amplitudes and to be used, upon supersymmetrization, as initial sources of deformation for the non-linear higher-derivative generalizations of the linear twisted self-duality condition. We show, however, that the new invariants are inconsistent with the expected UV divergent amplitudes in extended supergravities with non-degenerate duality groups of type E7. When E 7(7) degenerates into U(1) the new invariants reproduce the recently discovered source of deformation for the Born-Infeld duality invariant model with higher derivatives relevant to UV divergences of the D3 brane action. These facts may explain the UV properties of perturbative supergravity.

Kallosh, Renata; Ort?n, Tomás

2012-09-01

161

Prognostic significance of immunohistochemical expression of the HER2\\/neu oncoprotein in bone metastatic prostate cancer  

Microsoft Academic Search

ObjectivesTo investigate the usefulness of the overexpression of the human epidermal growth factor receptor (HER-2) oncoprotein in patients with bone metastatic prostate cancer as a marker for the time to recurrence and outcome after endocrine therapy.

Yoshitaka Nishio; Yoshiaki Yamada; Hiroto Kokubo; Kogenta Nakamura; Shigeyuki Aoki; Tomohiro Taki; Nobuaki Honda; Atsuko Nakagawa; Shinsuke Saga; Kazuo Hara

2006-01-01

162

Actin-dependent activation of serum response factor in T cells by the viral oncoprotein tip  

PubMed Central

Serum response factor (SRF) acts as a multifunctional transcription factor regulated by mutually exclusive interactions with ternary complex factors (TCFs) or myocardin-related transcription factors (MRTFs). Binding of Rho- and actin-regulated MRTF:SRF complexes to target gene promoters requires an SRF-binding site only, whereas MAPK-regulated TCF:SRF complexes in addition rely on flanking sequences present in the serum response element (SRE). Here, we report on the activation of an SRE luciferase reporter by Tip, the viral oncoprotein essentially contributing to human T-cell transformation by Herpesvirus saimiri. SRE activation in Tip-expressing Jurkat T cells could not be attributed to triggering of the MAPK pathway. Therefore, we further analyzed the contribution of MRTF complexes. Indeed, Tip also activated a reporter construct responsive to MRTF:SRF. Activation of this reporter was abrogated by overexpression of a dominant negative mutant of the MRTF-family member MAL. Moreover, enrichment of monomeric actin suppressed the Tip-induced reporter activity. Further upstream, the Rho-family GTPase Rac, was found to be required for MRTF:SRF reporter activation by Tip. Initiation of this pathway was strictly dependent on Tip's ability to interact with Lck and on the activity of this Src-family kinase. Independent of Tip, T-cell stimulation orchestrates Src-family kinase, MAPK and actin pathways to induce SRF. These findings establish actin-regulated transcription in human T cells and suggest its role in viral oncogenesis.

2012-01-01

163

The oncoprotein gankyrin interacts with RelA and suppresses NF-{kappa}B activity  

SciTech Connect

Gankyrin is an oncoprotein commonly overexpressed in hepatocellular carcinomas. It interacts with multiple proteins and accelerates degradation of tumor suppressors Rb and p53. Since gankyrin consists of 7 ankyrin repeats and is structurally similar to I{kappa}Bs, we investigated its interaction with NF-{kappa}B. We found that gankyrin directly binds to RelA. In HeLa and 293 cells, overexpression of gankyrin suppressed the basal as well as TNF{alpha}-induced transcriptional activity of NF-{kappa}B, whereas down-regulation of gankyrin increased it. Gankyrin did not affect the NF-{kappa}B DNA-binding activity or nuclear translocation of RelA induced by TNF{alpha} in these cells. Leptomycin B that inhibits nuclear export of RelA suppressed the NF-{kappa}B activity, which was further suppressed by gankyrin. The inhibitory effect of gankyrin was abrogated by nicotinamide as well as down-regulation of SIRT1, a class III histone deacetylase. Thus, gankyrin binds to NF-{kappa}B and suppresses its activity at the transcription level by modulating acetylation via SIRT1.

Higashitsuji, Hiroaki [Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan)], E-mail: hhigashi@virus.kyoto-u.ac.jp; Higashitsuji, Hisako; Liu, Yu; Masuda, Tomoko; Fujita, Takanori; Abdel-Aziz, H. Ismail [Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Kongkham, Supranee; Dawson, Simon; John Mayer, R. [Laboratory of Intracellular Proteolysis, School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH (United Kingdom); Itoh, Yoshito [Molecular Gastroenterology and Hepatology, Graduate School of Medical Sciences, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Sakurai, Toshiharu; Itoh, Katsuhiko [Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Fujita, Jun [Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan)], E-mail: jfujita@virus.kyoto-u.ac.jp

2007-11-23

164

Papillomavirus E6 oncoprotein up-regulates occludin and ZO-2 expression in ovariectomized mice epidermis.  

PubMed

We have studied the expression of the tight junction proteins (TJ) occludin, claudin-1 and ZO-2 in the epidermis of female mice. We observed a peak of expression of these proteins at postnatal day 7 and a decrease in 6 week-old mice to values similar to those found in newborn animals. We explored if the expression of the E6 oncoprotein from high-risk human papilloma virus type 16 (HPV16) in the skin of transgenic female mice (K14E6), altered TJ protein expression in a manner sensitive to ovarian hormones. We observed that in ovariectomized mice E6 up-regulates the expression of occludin and ZO-2 in the epidermis and that this effect was canceled by 17?-estradiol. Progesterone instead induced occludin and ZO-2 over-expression. However, the decreased expression of occludin and ZO-2 induced by 17?-estradiol in the epidermis was not overturned by E6 or progesterone. In addition, we employed MDCK cells transfected with E6, and observed that ZO-2 delocalizes from TJs and accumulates in the cell nuclei due to a decrease in the turnover rate of the protein. These results reinforce the view of 17?-estradiol and E6 as risk factors for the development of cancer through effects on expression and mislocalization of TJ proteins. PMID:23948304

Hernández-Monge, Jesús; Garay, Erika; Raya-Sandino, Arturo; Vargas-Sierra, Orlando; Díaz-Chávez, José; Popoca-Cuaya, Marco; Lambert, Paul F; González-Mariscal, Lorenza; Gariglio, Patricio

2013-08-12

165

The HPV16 E6 and E7 proteins and the radiation resistance of cervical carcinoma  

Microsoft Academic Search

Using a murine transplantation model, we have investigated the function of the HPV16 E6 and E7 proteins in the development of radiation resistance in advanced cervical carcinoma. Constitutive high-level expression of the HPV16 E6 oncogene in HPV negative human C33A cervical carcinoma cells was shown to induce rapid onset and radiation resistance in transplanted tumors when compared with tumors derived

Lynne Hampson; James V. Moore; Henry Kitchener; Ian N. Hampson

2001-01-01

166

HPV18 E1^E4 is assembled into aggresome-like compartment and involved in sequestration of viral oncoproteins.  

PubMed

Papillomavirus is the etiological agent for warts and several squamous carcinomas. Skin cancer induced by cottontail rabbit papillomavirus was the first animal model for virus-induced carcinogenesis. The target organ of the virus infection is stratified epithelium and virus replication is tightly regulated by the differentiation program of the host cell. E1^E4 protein is a viral gene product, and although it is considered to be involved in the control of virus replication, little is known about the biological role. We found that HPV18 E1^E4 was assembled into an aggresome-like compartment and was involved in sequestration of virus oncoproteins, which might contribute to the differentiation-dependent lifecycle of papillomavirus. PMID:23986755

Kajitani, Naoko; Satsuka, Ayano; Yoshida, Satoshi; Sakai, Hiroyuki

2013-08-27

167

Detection of human papillomavirus DNA and oncoprotein overexpression are associated with distinct morphological patterns of tonsillar squamous cell carcinoma.  

PubMed Central

Human papillomavirus (HPV) DNA has been detected in approximately 15% of squamous cell carcinomas (SCCs) of the head and neck. Recent studies have shown a predilection of HPV for certain anatomical sites, especially the tonsillar region, with viral DNA identified in approximately 60% of SCCs of the Waldeyer's tonsillar ring. This study was undertaken to determine whether there are differences in morphology or in oncogene expression in SCC of the tonsil with and without detectable HPV DNA. Twenty-two SCCs of the tonsil were analyzed for the presence of HPV DNA by polymerase chain reaction (PCR) using both a consensus primer set (My09/My11) and type-specific primers. Viral transcription was established in both primary and metastatic tumors by RNA in situ hybridization. The morphology of invasive SCC was classified into three subtypes: well keratinized (K-SCC), intermediate keratinized (I-SCC), and poorly keratinized (P-SCC). Expression of p53, pRB, and cyclin D1 (bcl-1) were studied by immunohistochemistry. In these cases (6 K-SCCs, 2 I-SCCs, and 14 P-SCCs), HPV DNA was detected in 14 (64%), with 11 containing HPV-16 (10 P-SCCs, 1 I-SCCs, and 0 K-SCCs) and 1 each containing HPV-33, HPV-59, and an unclassified HPV type (all P-SCCs). Viral oncoprotein E6/E7 transcription was demonstrated in 7 of 7 HPV-16-positive tumors. Cyclin D1 protein overexpression was detected in the majority of HPV-negative tumors (7 of 8 cases), whereas it was minimal or absent in 13 HPV-positive tumors. Overexpression of p53 protein was detected in 3 HPV-negative K-SCCs. In the HPV-positive tumors, fewer malignant cells expressed pRB and the staining was less intense than in the HPV-negative cancers. HPV DNA and E6/E7 expression, especially HPV-16, is detected in the majority of tonsillar SCCs and is almost exclusively associated with a poorly keratinized tumor histology. Decreased expression of cyclin D1, pRB, and p53 in tumors with HPV DNA is consistent with the known effects of the viral oncoproteins on the cellular protein. The morphology of the HPV-positive tumors suggests that HPV may have a predilection for a population of nonkeratinizing squamous cells or that the virally transformed cells inhibit keratinization of the tumor cells. Well keratinized tonsillar SCCs lack HPV DNA and are associated with overexpression of cyclin D1 protein and/or p53, suggesting that mechanisms that alter the cell cycle regulatory proteins, either by interaction with viral oncoproteins or by changes in the cellular proteins themselves, is critical for tumorigenesis of tonsillar SCC. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Wilczynski, S. P.; Lin, B. T.; Xie, Y.; Paz, I. B.

1998-01-01

168

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

169

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

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

2010-07-04

170

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.

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

2010-01-01

171

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

PubMed Central

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.

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

2013-01-01

172

The v-sis protein retains biological activity as a type II membrane protein when anchored by various signal-anchor domains, including the hydrophobic domain of the bovine papilloma virus E5 oncoprotein  

PubMed Central

Membrane-anchored forms of the v-sis oncoprotein have been previously described which are oriented as type I transmembrane proteins and which efficiently induce autocrine transformation. Several examples of naturally occurring membrane-anchored growth factors have been identified, but all exhibit a type I orientation. In this work, we wished to construct and characterize membrane-anchored growth factors with a type II orientation. These experiments were designed to determine whether type II membrane-anchored growth factors would in fact exhibit biological activity. Additionally, we wished to determine whether the hydrophobic domain of the E5 oncoprotein of bovine papilloma virus (BPV) can function as a signal-anchor domain to direct type II membrane insertion. Type II derivatives of the v-sis oncoprotein were constructed, with the NH2 terminus intracellular and the COOH terminus extracellular, by substituting the NH2 terminal signal sequence with the signal-anchor domain of a known type II membrane protein. The signal-anchor domains of neuraminidase (NA), asialoglycoprotein receptor (ASGPR) and transferrin receptor (TR) all yielded biologically active type II derivatives of the v-sis oncoprotein. Although transforming all of the type II signal/anchor-sis proteins exhibited a very short half-life. The short half-life exhibited by the signal/anchor-sis constructs suggests that, in some cases, cellular transformation may result from the synthesis of growth factors so labile that they activate undetectable autocrine loops. The E5 oncoprotein encoded by BPV exhibits amino acid sequence similarity with PDGF, activates the PDGF beta-receptor, and thus resembles a miniature membrane-anchored growth factor with a putative type II orientation. The hydrophobic domain of the E5 oncoprotein, when substituted in place of the signal sequence of v-sis, was indistinguishable compared with the signal-anchor domains of NA, TR, and ASGPR, demonstrating its ability to function as a signal-anchor domain. NIH 3T3 cells transformed by the signal/anchor-sis constructs exhibited morphological reversion upon treatment with suramin, indicating a requirement for ligand/receptor interactions in a suramin- sensitive compartment, most likely the cell surface. In contrast, NIH 3T3 cells transformed by the E5 oncoprotein did not exhibit morphological reversion in response to suramin.

1993-01-01

173

Interactions with Pocket Proteins Contribute to the Role of Human Papillomavirus Type 16 E7 in the Papillomavirus Life Cycle  

PubMed Central

Human papillomaviruses (HPVs), most commonly the HPV16 genotype, are the principle etiological determinant for cervical cancer, a common cancer worldwide resulting in over 200,000 deaths annually. The oncogenic properties of HPVs are attributable in part to the virally encoded protein E7, best known for its ability to bind to and induce the degradation of the retinoblastoma tumor suppressor, pRb, and related “pocket proteins” p107 and p130. Previously, we defined a role for E7 in the productive stage of the HPV16 life cycle, which takes place in stratified squamous epithelia. HPV perturbs the normal processes of cell growth and differentiation of stratified squamous epithelia. HPVs reprogram cells to support continued DNA synthesis and inhibit their differentiation in the suprabasal compartment of the epithelia, where cells normally have withdrawn from the cell cycle and initiated a well-defined pattern of terminal differentiation. These virus-induced perturbations, which contribute to the production of progeny HPVs, are dependent on E7. In this study, we define the mechanism of action by which E7 contributes to the productive stage of the HPV16 life cycle. We found that the ability of HPV16 to reprogram suprabasal cells to support DNA synthesis correlates with E7's ability to bind pocket proteins but not its ability to induce their degradation. In contrast, the ability of HPV16 to perturb differentiation correlated with both E7's binding to and degradation of pocket proteins. These data indicate that different hallmarks of the productive stage of the HPV16 life cycle rely upon different sets of requirements for E7.

Collins, Asha S.; Nakahara, Tomomi; Do, Anh; Lambert, Paul F.

2005-01-01

174

N-myc gene expression and oncoprotein characterisation in medulloblastoma.  

PubMed Central

Although medulloblastoma and neuroblastoma share many common biological, histological and immunological features, the frequency of N-myc amplification differs markedly between the two tumours. In this study, Southern blot analysis revealed that the N-myc gene was not amplified in any of the nine medulloblastoma samples analysed. In contrast, over-expression of the gene was found in six of 11 samples as determined by immunocytochemistry and/or Western blot analysis, using an antiserum raised against a synthetic peptide representing a sequence unique to the N-myc gene product. The specificity of this reagent was demonstrated by studies on a variety of cell lines expressing N-myc and/or c-myc oncoproteins. Of the 12 medulloblastoma samples collected over a two-year period and analysed in the course of this project, a trend towards longer disease-free survival was noted in the patients having low levels of the N-myc protein in their tumour. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Garson, J. A.; Pemberton, L. F.; Sheppard, P. W.; Varndell, I. M.; Coakham, H. B.; Kemshead, J. T.

1989-01-01

175

Structure of the oncoprotein Rcl bound to three nucleotide analogues.  

PubMed

Rcl is a novel N-glycoside hydrolase found in mammals that shows specificity for the hydrolysis of 5'-monophosphate nucleotides. Its role in nucleotide catabolism and the resulting production of 2-deoxyribose 5-phosphate has suggested that it might fuel cancer growth. Its expression is regulated by c-Myc, but its role as an oncoprotein remains to be clarified. In parallel, various nucleosides have been shown to acquire pro-apoptotic properties upon 5'-monophosphorylation in cells. These include triciribine, a tricyclic nucleoside analogue that is currently in clinical trials in combination with a farnesyltransferase inhibitor. Similarly, an N(6)-alkyl-AMP has been shown to be cytotoxic. Interestingly, Rcl has been shown to be inhibited by such compounds in vitro. In order to gain better insight into the precise ligand-recognition determinants, the crystallization of Rcl with these nucleotide analogues was attempted. The first crystal structure of Rcl was solved by molecular replacement using its NMR structure in combination with distantly related crystal structures. The structures of Rcl bound to two other nucleotides were then solved by molecular replacement using the previous crystal structure as a template. The resulting structures, solved at high resolution, led to a clear characterization of the protein-ligand interactions that will guide further rational drug design. PMID:23385460

Padilla, André; Amiable, Claire; Pochet, Sylvie; Kaminski, Pierre Alexandre; Labesse, Gilles

2013-01-19

176

Control of cervicovaginal HPV-16 E7-expressing tumors by the combination of therapeutic HPV vaccination and vascular disrupting agents.  

PubMed

Abstract Antigen-specific immunotherapy and vascular disrupting agents, such as 5,6-dimethylxanthenone-4-acetic acid (DMXAA), have emerged as attractive approaches for the treatment of cancers. In the current study, we tested the combination of DMXAA treatment with therapeutic human papillomavirus type 16 (HPV-16) E7 peptide-based vaccination for their ability to generate E7-specific CD8+ T-cell immune responses, as well as their ability to control E7-expressing tumors in a subcutaneous and a cervicovaginal tumor model. We found that the combination of DMXAA treatment with E7 long peptide (amino acids 43-62) vaccination mixed with polyriboinosinic:polyribocytidylic generated significantly stronger E7-specific CD8+ T-cell immune responses and antitumor effects compared with treatment with DMXAA alone or HPV peptide vaccination alone in the subcutaneous model. Additionally, we found that the DMXAA-mediated enhancement of E7-specific CD8+ T-cell immune responses generated by the therapeutic HPV peptide-based vaccine was dependent on the timing of administration of DMXAA. Treatment with DMXAA in tumor-bearing mice was also shown to lead to increased dendritic cell maturation and increased production of inflammatory cytokines in the tumor. Furthermore, we observed that the combination of DMXAA with HPV-16 E7 peptide vaccination generated a significant enhancement in the antitumor effects in the cervicovaginal TC-1 tumor growth model, which closely resembles the tumor microenvironment of cervical cancer. Taken together, our data demonstrated that administration of the vascular disrupting agent, DMXAA, enhances therapeutic HPV vaccine-induced cytotoxic T-lymphocyte responses and antitumor effects against E7-expressing tumors in two different locations. Our study has significant implications for future clinical translation. PMID:21128743

Zeng, Qi; Peng, Shiwen; Monie, Archana; Yang, Ming; Pang, Xiaowu; Hung, Chien-Fu; Wu, T-C

2011-03-09

177

A Conserved E7-derived Cytotoxic T Lymphocyte Epitope Expressed on Human Papillomavirus 16-transformed HLA-A2+ Epithelial Cancers  

PubMed Central

Human Papillomavirus 16 (HPV-16) has been identified as the causative agent of 50% of cervical cancers and many other HPV-associated tumors. The transforming potential/tumor maintenance capacity of this high risk HPV is mediated by two viral oncoproteins, E6 and E7, making them attractive targets for therapeutic vaccines. Of 21 E6 and E7 peptides computed to bind HLA-A*0201, 10 were confirmed through TAP-deficient T2 cell HLA stabilization assay. Those scoring positive were investigated to ascertain which were naturally processed and presented by surface HLA molecules for CTL recognition. Because IFN? ELISpot frequencies from healthy HPV-exposed blood donors against HLA-A*0201-binding peptides were unable to identify specificities for tumor targeting, their physical presence among peptides eluted from HPV-16-transformed epithelial tumor HLA-A*0201 immunoprecipitates was analyzed by MS3 Poisson detection mass spectrometry. Only one epitope (E711–19) highly conserved among HPV-16 strains was detected. This 9-mer serves to direct cytolysis by T cell lines, whereas a related 10-mer (E711–20), previously used as a vaccine candidate, was neither detected by MS3 on HPV-transformed tumor cells nor effectively recognized by 9-mer specific CTL. These data underscore the importance of precisely defining CTL epitopes on tumor cells and offer a paradigm for T cell-based vaccine design.

Riemer, Angelika B.; Keskin, Derin B.; Zhang, Guanglan; Handley, Maris; Anderson, Karen S.; Brusic, Vladimir; Reinhold, Bruce; Reinherz, Ellis L.

2010-01-01

178

Podophyllotoxin directly binds a hinge domain in E2 of HPV and inhibits an E2/E7 interaction in vitro.  

PubMed

Podophyllotoxin (PT), a strong cytotoxic agent from berberidaceae, has been known to inhibit tubulin polymerization. Although PT has been used for developing anticancer drugs as one of seed compounds, clinical treatment by itself has been unsuccessful because of the side effects, except one example in the treatments of warts. In this study, we screened peptides binding to PT with T7 phage display clonings in order to obtain more information about molecular mechanism of the action. A selected phage clone has a specific amino acid sequence to be SVPSRRRPDGRTHRSSRG. A homology search by protein database BLAST showed that this sequence had a similarity to a hinge domain (HD) of E2 protein in human papillomavirus (HPV) type 1a which is known to cause plantar warts. Surface plasmon resonance (SPR) analysis showed that PT bound to a recombinant HPV 1a E2 protein giving a K(D)=24.1microM which has compared with those of other domains of E2 protein. Also we demonstrated whether PT inhibited HD interaction or not. E7 protein of HPV has been known to be an oncoprotein and was reported to interact with HD of E2 protein. We demonstrated that an E2/E7 interaction was inhibited by the addition of PT in this report. And we showed the bindings of PT to other types of HPV. Our results suggest that PT is potential as a tool for clarifying the molecular mechanism of HPV. PMID:18396405

Saitoh, Takeki; Kuramochi, Kouji; Imai, Takahiko; Takata, Kei-ichi; Takehara, Masahide; Kobayashi, Susumu; Sakaguchi, Kengo; Sugawara, Fumio

2008-03-25

179

SnoN oncoprotein enhances estrogen receptor-? transcriptional activity.  

PubMed

Estrogen receptor-? (ER?) and transforming growth factor-beta (TGF-?) signaling pathways are essential regulators during mammary gland development and tumorigenesis. Ski-related novel gene (SnoN) is an oncoprotein and a negative feedback inhibitor of TGF-? signaling. We have previously reported that low expression of SnoN in ER? positive breast carcinomas is associated with favorable prognosis (Zhang et al. Cancer Res. (2003) 63, 5005-5010). Here we have studied the mechanism of a possible cross-talk between ER? and SnoN. We find that SnoN interacts with the estrogen-activated form of ER? in the nucleus. SnoN contains two highly conserved nuclear receptor binding LxxLL-like motifs and we show that mutations in these motifs reduce the interaction of SnoN with ER?. Over-expression of SnoN enhanced the transcriptional activity of ER? in estrogen response element (ERE)-reporter assays, augmented the expression of several ER? target genes and increased the proliferation of MCF7 breast carcinoma cells in an estrogen-dependent manner. Chromatin immunoprecipitation demonstrated that SnoN interacts with ER? at the TTF1 (pS2) gene promoter. Conversely, silencing of SnoN reduced both ERE-reporter activity and the expression of ER? target genes in MCF7 and T-47D breast cancer cells. Histone deacetylase inhibition increased the level of SnoN and SnoN-dependent enhancement of ER?-dependent transcription and SnoN supported the recruitment of p300 histone acetylase to ER?. This study reveals a novel mechanism that interconnects ER? and TGF-? signaling pathways by SnoN. Accordingly, the results indicate that high SnoN level promotes ER? signaling and possibly breast cancer progression. PMID:22227247

Band, Arja M; Laiho, Marikki

2011-12-29

180

E6 and E7 of human papillomavirus type 18 and UVB irradiation corporately regulate interleukin-6 and interleukin-8 expressions in basal cell carcinoma.  

PubMed

The lack of a human papillomavirus (HPV)-infected skin cancer cell line has hampered the investigation of the interaction of UV and HPV in skin carcinogenesis. We identified a human basal cell carcinoma (BCC-1/KMC) cell line integrated with E6 and E7 genes of high-risk HPV type 18 and demonstrated that repression of E6 and E7 results in proliferation inhibition. Sublethal ultraviolet-B (UVB) irradiation induced the expressions of interleukin-6 (IL-6) and interleukin-8 (IL-8), as well as viral E6 and E7 genes, in BCC-1/KMC cells. When E6 and E7 expressions were inhibited, IL-6/IL-8 expressions were repressed. Furthermore, IL-6/IL-8 remained inducible by UVB irradiation when E6 and E7 were inhibited. These results indicated that IL-6 and IL-8 can be upregulated by viral E6 and E7 proteins without UVB irradiation. Moreover, chronic exposure to UVB upregulates IL-6 and IL-8 when E6/E7 is induced by UVB. PMID:24079741

Hsiao, Yu-Ping; Yang, Jen-Hung; Wu, Wen-Jun; Lin, Meng-Hsuan; Sheu, Gwo-Tarng

2013-10-01

181

E(7(7)) and d=11 supergravity  

NASA Astrophysics Data System (ADS)

This thesis firstly investigates whether D=11 supergravity can be lifted to a higher dimensional theory without introducing additional bosonic fields by interpreting the E(7(7))-symmetry of N=8 d=4 supergravity as part of a coordinate symmetry acting in a 60 dimensional restricted or exceptional geometry. It is proved that the supersymmetry variations of D=11 supergravity, truncated to d=7, can be reproduced from this exceptional geometry in the expected manner. Secondly, Borisov's and Ogievetsky's procedure to construct a theory with diffeomorphism covariance from the joint non-linear realization of the affine linear subgroup of diffeomorphisms with the conformal one is reviewed in detail, which is then extended by discussing torsion in this context.

Hillmann, Christian

2009-02-01

182

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.

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

2011-01-01

183

MUC1-C Oncoprotein Interacts Directly with ATM and Promotes the DNA Damage Response to Ionizing Radiation  

PubMed Central

The ataxia-telangiectasia mutated (ATM) kinase is activated in the cellular response to ionizing radiation (IR) and is of importance to the repair of DNA double-strand breaks (DSBs). The MUC1 oncoprotein is aberrantly overexpressed in human breast carcinomas. The present work demonstrates that the MUC1 C-terminal subunit (MUC1-C) constitutively interacts with ATM in human breast cancer cells. The authors show that the MUC1-C cytoplasmic domain binds directly to ATM HEAT repeats. The results also demonstrate that the MUC1-C cytoplasmic domain binds to the ATM substrate H2AX. The functional significance of these interactions is supported by the finding that MUC1-C promotes removal of IR-induced nuclear ?H2AX foci. MUC1-C also protects against IR-induced chromosomal aberrations. In concert with these results, MUC1-C blocks IR-induced death by promoting repair of potentially lethal DNA damage. These findings indicate that the overexpression of MUC1 can protect against IR-induced DNA DSBs and may represent a physiologic response that has been exploited by malignant cells.

Huang, Lei; Liao, Xiaodong; Beckett, Michael; Li, Yuan; Khanna, Kum Kum; Wang, Zhugang; Kharbanda, Surender; Weichselbaum, Ralph; Kufe, Donald

2010-01-01

184

High-risk HPV E5-induced cell fusion: a critical initiating event in the early stage of HPV-associated cervical cancer  

PubMed Central

Background Cervical cancer is strongly associated with high-risk human papillomavirus (HPV) and viral oncoproteins E5, E6 and E7 can transform cells by various mechanisms. It is proposed that oncogenic virus-induced cell fusion may contribute to oncogenesis if p53 or apoptosis is perturbed simultaneously. Recently, HPV-16 E5 was found to be necessary and sufficient for the formation of tetraploid cells, which are frequently found in precancerous cervical lesions and its formation is strongly associated with HPV state. Presentation of the hypothesis We propose that high-risk HPV E5-induced cell fusion is a critical initiating event in the early stage of HPV-associated cervical cancer. Testing the hypothesis Our hypothesis can be tested by comparing the likelihood for colony formation or tumorigenic ability in nude mice between normal HaCaT cells expressing all three oncogenic proteins and E5-induced bi-nucleated HaCaT cells expressing E6 and E7. Moreover, investigating premature chromosome condensation (PCC) in HPV-positive and negative precancerous cervical cells is another way to assess this hypothesis. Implication of the hypothesis This viewpoint would change our understanding of the mechanisms by which HPV induces cervical cancer. According to this hypothesis, blocking E5-induced cell fusion is a promising way to prevent the progression of cervical cancer. Additionally, establishment of a role of cell fusion in cervical carcinogenesis is of reference value for understanding the pathogenesis of other virus-associated cancers.

2010-01-01

185

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

186

MUC1 Oncoprotein Promotes Refractoriness to Chemotherapy in Thyroid Cancer Cells  

Microsoft Academic Search

Overexpression of MUC1 oncoprotein is frequently observed in cancer and contributes to confer resistance to genotoxic agents. Papillary, follicular, and anaplastic thyroid carcino- mas are the three forms of thyroid epithelial cancer. Anaplastic tumors are less differentiated and extremely aggressive, characterized by a poor prognosis. Little is known about the role of MUC1 in thyroid cancer. We recently showed that

Mauro Siragusa; Monica Zerilli; Flora Iovino; Maria Giovanna Francipane; Ylenia Lombardo; Lucia Ricci-Vitiani; Giuseppe Di Gesu; Matilde Todaro; Ruggero De Maria; Giorgio Stassi

2007-01-01

187

HSP70 and modified HPV 16 E7 fusion gene without the addition of a signal peptide gene sequence as a candidate therapeutic tumor vaccine.  

PubMed

Millions of women are currently infected with high-risk human papillomavirus (HPV), which is considered to be a major risk factor for cervical cancer. Thus, it is urgent to develop therapeutic vaccines to eliminate the established infections or HPV-related diseases. In the present study, using the mycobacterium tuberculosis heat shock protein 70 (MtHSP70) gene linked to the modified HPV 16 E7 (mE7) gene, we generated two potential therapeutic HPV DNA vaccines, mE7/MtHSP70 and SigmE7/MtHSP70, the latter was linked to the signal peptide gene sequence of human CD33 at the upstream of the fusion gene. We found that vaccination with the mE7/MtHSP70 DNA vaccine induced a stronger E7-specific CD8+ T cell response and resulted in a more significant therapeutic effect against E7-expressing tumor cells in mice. Our results demonstrated that HSP70 can play a more important role in mE7 and MtHSP70 fusion DNA vaccine without the help of a signal peptide. This may facilitate the use of HSP70 and serve as a significant reference for future study. PMID:24065282

Zong, Jinbao; Wang, Changyuan; Wang, Qingyong; Peng, Qinglin; Xu, Yufei; Xie, Xixiu; Xu, Xuemei

2013-09-20

188

Boosting with Recombinant Vaccinia Increases HPV16 E7Specific T Cell Precursor Frequencies and Antitumor Effects of HPV16 E7Expressing Sindbis Virus Replicon Particles  

Microsoft Academic Search

Immunotherapy using the heterologous prime–boost regimen has emerged as an attractive approach for generating antigen-specific T-cell-mediated immune responses against tumors and infectious diseases. We have previously linked the Mycobacterium tuberculosis heat-shock protein 70 (HSP70) to the HPV-16 E7 antigen creating a chimera, E7\\/HSP70. We found that nucleic acid vaccines encoding E7\\/HSP70 can generate strong antitumor immunity. Recently, replication-defective Sindbis virus

Cheng-Tao Lin; Chien-Fu Hung; Jeremy Juang; Liangmei He; Ken-Yu Lin; Tae WooKim; T.-C. Wu

2003-01-01

189

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

190

Human papillomavirus type 16 E6/E7-specific cytotoxic T lymphocytes for adoptive immunotherapy of HPV-associated malignancies.  

PubMed

Vaccines prevent human papillomavirus (HPV)-associated cancer but, although these tumors express foreign, viral antigens (E6 and E7 proteins), they have little benefit in established malignancies, likely due to negative environmental cues that block tumor recognition and induce T-cell anergy in vivo. We postulated that we could identify mechanisms by which ex vivo stimulation of T cells could reactivate and expand tumor-directed T-cell lines from HPV cancer patients for subsequent adoptive immunotherapy. A total of 68 patients with HPV-associated cancers were studied. Peripheral blood T cells were stimulated with monocyte-derived dendritic cells loaded with pepmixes [peptide libraries of 15-mers overlapping by 11 amino acids (aa)] spanning E6/E7, in the presence or absence of specific accessory cytokines. The resulting T-cell lines were further expanded with pepmix-loaded activated B-cell blasts. Interferon-? release and cytotoxic responses to E6/E7 were assessed. We successfully reactivated and expanded (>1200-fold) E6-specific/E7-specific T cells from 8/16 cervical and 33/52 oropharyngeal cancer patients. The presence of the cytokines interleukin (IL)-6, IL-7, IL-12, and IL-15 is critical for this process. These T-cell lines possess the desirable characteristics of polyclonality, multiple T-cell subset representation (including the memory compartment) and a TH1 bias, and may eliminate E6/E7 targets. In conclusion, we have shown it is possible to robustly generate HPV16 E6/E7-directed T-cell lines from patients with HPV16-associated cancers. Because our technique is scalable and good-manufacturing procedures-compliant, these lines could be used for adoptive cellular immunotherapy of patients with HPV16 cancers. PMID:23211628

Ramos, Carlos A; Narala, Neeharika; Vyas, Gayatri M; Leen, Ann M; Gerdemann, Ulrike; Sturgis, Erich M; Anderson, Matthew L; Savoldo, Barbara; Heslop, Helen E; Brenner, Malcolm K; Rooney, Cliona M

2013-01-01

191

Preclinical development of highly effective and safe DNA vaccines directed against HPV 16 E6 and E7.  

PubMed

To allow vaccination irrespective of HLA type, DNA vaccines encoding full-length antigens are required. However, here, we demonstrate that the immunogenicity of DNA vaccines encoding the full-length human papillomavirus (HPV) type 16 E7 and E6 proteins is highly reduced compared to vaccines encoding only the immunodominant epitope. Furthermore, the low remaining immunogenicity is essentially lost for both E7 and E6 when a nononcogenic "gene-shuffled" variant is utilized. To address these issues, we tested whether alterations in transgene design can restore the immunogenicity of full-length and gene-shuffled DNA vaccines. Remarkably, genetic fusion of E7 with tetanus toxin fragment C (TTFC) resulted in a dramatic increase in immunogenicity both for the full-length and the gene-shuffled version of E7. Moreover, the TTFC fusion vaccines were more immunogenic than a vaccine encoding a fusion of E7 and mycobacterial heat shock protein-70, which has recently been tested in a clinical trial. Interestingly, vaccination with these TTFC fusion vaccines also resulted in extremely persistent T-cell responses. The E7-specific CD8(+) T cells induced by TTFC fusion vaccines were functional in terms of IFN-? production, formation of immunological memory, in vivo cytolytic activity and tumor eradication. Finally, we show that genetic fusion with TTFC also improves the immunogenicity of a gene-shuffled E6 DNA vaccine. These data demonstrate that genetic fusion with tetanus toxin fragment C can dramatically improve the immunogenicity of full-length and gene-shuffled DNA vaccines. The DNA fusion vaccines developed here will be evaluated for the treatment of HPV-positive carcinomas in future studies. PMID:21207427

Oosterhuis, Koen; Ohlschläger, Peter; van den Berg, Joost H; Toebes, Mireille; Gomez, Raquel; Schumacher, Ton N; Haanen, John B

2011-04-27

192

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

193

Myb-Ets fusion oncoprotein inhibits thyroid hormone receptor/c-ErbA and retinoic acid receptor functions: a novel mechanism of action for leukemogenic transformation by E26 avian retrovirus.  

PubMed Central

The E26 and avian erythroblastosis virus (AEV) avian retroviruses induce acute leukemia in chickens. E26 can block both erythroid and myeloid differentiation at an early multipotent stage. Moreover, E26 can block erythroid differentiation at the erythroid burst-forming unit/erythroid CFU (BFU-E/CFU-E) stage, which also corresponds to the differentiation stage blocked by AEV. AEV carries two oncogenes, v-erbA and v-erbB, whereas E26 encodes a single 135-kDa Gag-Myb-Ets fusion oncoprotein. v-ErbA is responsible for the erythroid differentiation arrest through negative interferences with both the retinoic acid receptor (RAR) and the thyroid hormone receptor (T3R/c-ErbA). We investigated whether Myb-Ets could block erythroid differentiation in a manner similar to v-ErbA. We show here that Myb-Ets inhibits both RAR and c-ErbA activities on specific hormone response elements in transient-expression assays. Moreover, Myb-Ets abrogates the inactivation of transcription factor AP-1 by RAR and T3R, another feature shared with v-ErbA. Myb-Ets also antagonizes the biological response of erythrocytic progenitor cells to retinoic acid and T3. Analysis of a series of mutants of Myb-Ets reveals that the domains of the oncoprotein involved in these inhibitory activities are the same as those involved in oncogenic transformation of hematopoietic cells. These data demonstrate that the Myb-Ets oncoprotein shares properties with the v-ErbA oncoprotein and that inhibition of ligand-dependent RAR and c-ErbA functions by Myb-Ets is responsible for blocking the differentiation of hematopoietic progenitors.

Rascle, A; Ferrand, N; Gandrillon, O; Samarut, J

1996-01-01

194

Increased serum remnant lipoproteins in patients with apolipoprotein E7 (apo E Suita)  

Microsoft Academic Search

Apolipoprotein (apo) E7 was originally identified by Yamamura et al. in subjects with atherosclerotic cardiovascular diseases (J. Clin. Invest. 1984;74:1229). However, the lipoprotein abnormalities associated with apo E7 phenotype have not been elucidated. In the current study, to clarify the physiological roles of apo E7, lipoprotein abnormalities were studied in 12 apo E7 heterozygotes. A total of seven subjects were

Koji Yanagi; Shizuya Yamashita; Hisatoyo Hiraoka; Masato Ishigami; Shinji Kihara; Ken-ichi Hirano; Naohiko Sakai; Shuichi Nozaki; Tohru Funahashi; Kaoru Kameda-Takemura; Masaharu Kubo; Katsuto Tokunaga; Yuji Matsuzawa

1997-01-01

195

Induction of apoptosis in human papillomaviruspositive cancer cells by peptide aptamers targeting the viral E6 oncoprotein  

Microsoft Academic Search

Certain types of human papillomaviruses (HPVs) are closely linked to the development of human cancers. Herein, it is shown that intracellular targeting of the HPV16 E6 oncoprotein by E6-binding peptide aptamers resulted in the apoptotic elimination of HPV16-positive cancer cells, whereas HPV-negative cells were not affected. These results provide direct experimental evidence that the HPV E6 oncoprotein has antiapoptotic activity

Karin Butz; Claudia Denk; Angela Ullmann; Martin Scheffner; Felix Hoppe-Seyler

2000-01-01

196

The HECT-domain ubiquitin ligase Huwe1 controls neural differentiation and proliferation by destabilizing the N-Myc oncoprotein  

Microsoft Academic Search

Development of the nervous system requires that timely withdrawal from the cell cycle be coupled with initiation of differentiation. Ubiquitin-mediated degradation of the N-Myc oncoprotein in neural stem\\/progenitor cells is thought to trigger the arrest of proliferation and begin differentiation. Here we report that the HECT-domain ubiquitin ligase Huwe1 ubiquitinates the N-Myc oncoprotein through Lys 48-mediated linkages and targets it

Xudong Zhao; Julian Ik-Tsen Heng; Daniele Guardavaccaro; Richeng Jiang; Michele Pagano; Francois Guillemot; Antonio Iavarone; Anna Lasorella

2008-01-01

197

Establishment and characterization of murine small cell lung carcinoma cell lines derived from HPV-16 E6/E7 transgenic mice.  

PubMed

We have established two murine cell lines derived from Small Cell Lung Carcinomas (SCLCs) developed by HPV-E6/E7 transgenic mice. These cells named PPAP-9 and PPAP-10 were isolated from mice bearing tumors, 9 and 10 months old, respectively. The cells, 5 microm in diameter, express HPV oncoproteins and sustain tumor formation after subcutaneous injection in syngenic mice. A detailed analysis indicated the epithelial origin and the neuroendocrine differentiation of these cells. We showed by confocal immunofluorescence the expression of the epithelial marker cytokeratin 5, whose gene promoter was used to direct the expression of HPV E6/E. Cells express several neuroendocrine markers such as CGRP, MAP-2, Ash1, CgrA, Scg2. The neuroendocrine differentiation of these cells was further confirmed by electron microscopy demonstrating neuropeptides secreting granules in their cytoplasm. Furthermore, in agreement with the altered expression observed in the majority of human SCLC we showed in these cells the absence of both p53 and pRB and a dramatic reduction in the expression of Caveolin-1. PMID:16356832

Carraresi, Laura; Martinelli, Rosanna; Vannoni, Alessandro; Riccio, Massimo; Dembic, Maja; Tripodi, Sergio; Cintorino, Marcella; Santi, Spartaco; Bigliardi, Elisa; Carmellini, Mario; Rossini, Mara

2006-01-01

198

Casein Kinase II Motif-Dependent Phosphorylation of Human Papillomavirus E7 Protein Promotes p130 Degradation and S-Phase Induction in Differentiated Human Keratinocytes?  

PubMed Central

The E7 proteins of human papillomaviruses (HPVs) promote S-phase reentry in differentiated keratinocytes of the squamous epithelia to support viral DNA amplification. In this study, we showed that nuclear p130 was present in the differentiated strata of several native squamous epithelia susceptible to HPV infection. In contrast, p130 was below the level of detection in HPV-infected patient specimens. In submerged and organotypic cultures of primary human keratinocytes, the E7 proteins of the high-risk mucosotrophic HPV-18, the benign cutaneous HPV-1, and, to a lesser extent, the low-risk mucosotropic HPV-11 destabilized p130. This E7 activity depends on an intact pocket protein binding domain and a casein kinase II (CKII) phosphorylation motif. Coimmunoprecipitation experiments showed that both E7 domains were important for binding to p130 in extracts of organotypic cultures. Metabolic labeling in vivo demonstrated that E7 proteins were indeed phosphorylated in a CKII motif-dependent manner. Moreover, the efficiencies of the E7 proteins of various HPV types or mutations to induce S-phase reentry in spinous cells correlated with their relative abilities to bind and to destabilize p130. Collectively, these data support the notion that p130 controls the homeostasis of the differentiated keratinocytes and is therefore targeted by E7 for degradation to establish conditions permissive for viral DNA amplification.

Genovese, Nicholas J.; Banerjee, N. Sanjib; Broker, Thomas R.; Chow, Louise T.

2008-01-01

199

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

200

Autophagic degradation of the BCR-ABL oncoprotein and generation of antileukemic responses by arsenic trioxide  

PubMed Central

We provide evidence that arsenic trioxide (As2O3) targets the BCR-ABL oncoprotein via a novel mechanism involving p62/SQSTM1-mediated localization of the oncoprotein to the autolysosomes and subsequent degradation mediated by the protease cathepsin B. Our studies demonstrate that inhibitors of autophagy or cathepsin B activity and/or molecular targeting of p62/SQSTM1, Atg7, or cathepsin B result in partial reversal of the suppressive effects of AS2O3 on BCR-ABL expressing leukemic progenitors, including primitive leukemic precursors from chronic myelogenous leukemia (CML) patients. Altogether, these findings indicate that autophagic degradation of BCR-ABL is critical for the induction of the antileukemic effects of As2O3 and raise the potential for future therapeutic approaches to target BCR-ABL expressing cells by modulating elements of the autophagic machinery to promote BCR-ABL degradation.

Goussetis, Dennis J.; Gounaris, Elias; Wu, Edward J.; Vakana, Eliza; Sharma, Bhumika; Bogyo, Matthew; Altman, Jessica K.

2012-01-01

201

Platelet-derived growth factor oncoprotein detection using three-dimensional carbon microarrays.  

PubMed

The potential of aptamers as ligand binding molecule has opened new avenues in the development of biosensors for cancer oncoproteins. In this paper, a label-free detection strategy using signaling aptamer/protein binding complex for platelet-derived growth factor (PDGF-BB) oncoprotein detection is reported. The detection mechanism is based on the release of fluorophore (TOTO intercalating dye) from the target binding aptamer's stem structure when it captures PDGF. Amino-terminated three-dimensional carbon microarrays fabricated by pyrolyzing patterned photoresist were used as a detection platform. The sensor showed near linear relationship between the relative fluorescence difference and protein concentration even in the sub-nanomolar range with an excellent detection limit of 5pmol. This detection strategy is promising in a wide range of applications in the detection of cancer biomarkers and other proteins. PMID:22841446

Penmatsa, Varun; Ruslinda, A Rahim; Beidaghi, Majid; Kawarada, Hiroshi; Wang, Chunlei

2012-07-20

202

Proliferative indices and oncoprotein expression in benign and malignant breast biopsies  

Microsoft Academic Search

Background: Prognostic factors are used routinely in the management of breast cancer. However, their potential for identifying precursor malignant lesions has not been assessed.\\u000aMethods: We have examined 285 breast biopsy specimens (140 benign, 145 malignant) for DNA ploidy, S-phase fraction, Ki-67 nuclear antigen proliferative indices, and HER-2\\/neu and epidermal growth factor receptor oncoproteins.\\u000aResults: When proliferative indices were compared

Steven T. Brower; Paul I. Tartter; Sharmila Ahmed; Cristina M. Brusco; Kathi Bossolt; Cheryl Hayden; Ira Bleiweiss

1995-01-01

203

Circulating oncoproteins HER2\\/neu, EGFR and CAIX (MN) as novel cancer biomarkers  

Microsoft Academic Search

Pharmaceutical companies have developed targeted therapies such as trastuzumab and lapatinib for human epidermal growth factor receptor (HER)2\\/neu-positive tumors, while others have developed antiepidermal growth factor receptor (EGFR) therapies, such as tarceva and erbitux for EGFR-positive tumors. A drug called rencarex is targeted to an oncoprotein designated carbonic anhydrase IX (CAIX), which is being evaluated in renal cell carcinoma patients.

Walter P Carney

2007-01-01

204

Overexpression of the Oncoprotein Prothymosin A Triggers a p53 Response that Involves p53 Acetylation  

Microsoft Academic Search

Activation of the tumor suppressor protein p53 is a critical cellular response to various stress stimuli and to inappropri- ate activity of growth-promoting proteins, such as Myc, Ras, E2F, and B-catenin. Protein stability and transcriptional activity of p53 are modulated by protein-protein interactions and post-translational modifications, including acetylation. Here, we show that inappropriate activity of prothymosin A (PTMA), an oncoprotein

Takahiko Kobayashi; Masaji Maezawa; Masanobu Kobayashi; Shunsuke Ohnishi; Kazuteru Hatanaka; Shuhei Hige; Yuichi Shimizu; Mototsugu Kato; Masahiro Asaka; Junji Tanaka; Masahiro Imamura; Kiminori Hasegawa; Yoshiyuki Tanaka; Rainer K. Brachmann

205

Human T-cell leukemia virus type-1 Tax oncoprotein regulates G-protein signaling  

Microsoft Academic Search

Human T-cell leukemia virus type-1 (HTLV-1) is associated with adult T-cell leukemia (ATL) and neurological syn- dromes. HTLV-1 encodes the oncoprotein Tax-1, which modulates viral and cellular gene expression leading to T-cell transfor- mation. Guanine nucleotide-binding pro- teins (G proteins) and G protein-coupled receptors (GPCRs) constitute the largest family of membrane proteins known and are involved in the regulation of

Jean-Claude Twizere; Jean-Yves Springael; Mathieu Boxus; Arsene Burny; Franck Dequiedt; Jean-Francois Dewulf; Julie Duchateau; Daniel Portetelle; Patrice Urbain; Carine Van Lint; Patrick L. Green; Renaud Mahieux; Marc Parmentier; Luc Willems; Richard Kettmann

2007-01-01

206

Role of oligomerization of the S13 Env-Sea oncoprotein in cell transformation.  

PubMed Central

The env-sea oncogene is a fusion of the S13 viral envelope gene, env, and cell-derived sequences encoding a tyrosine kinase domain, termed sea. The Env-Sea oncoprotein is synthesized as a precursor of 155 kDa which undergoes proteolytic processing to generate a disulfide-linked complex of the proteins gp85 and gp70. We analyzed the oligomeric state of the Env-Sea oncoprotein in S13-transformed cells and demonstrate that both gp155 and the gp85-gp70 complex can oligomerize. To address the relevance of these oligomers in transformation by S13, a mutant that is temperature sensitive for the transformed phenotype was used. The tyrosine-phosphorylated oligomers of gp155 were found at the nonpermissive temperature, and thus oligomerization per se appears to be insufficient to elicit a transformed phenotype. Efficient intracellular transport of gp155 appears to be required to generate a tyrosine-phosphorylated oligomer of the gp85-gp70 complex, the presence of which correlates with the transformed phenotype. This gp85-gp70 complex appeared to have a higher level of kinase activity than the other forms of the Env-Sea protein. These results suggest that oligomerization, transport, and intracellular localization represent levels at which the oncogenic activity of the Env-Sea oncoprotein may be regulated. Images

Morimoto, A M; Hayman, M J

1994-01-01

207

Prophylactic and therapeutic efficacy of an attenuated Listeria monocytogenes-based vaccine delivering HPV16 E7 in a mouse model.  

PubMed

Listeria monocytogenes (L. monocytogenes) has been developed as a cancer vaccine vector due to its ability to elicit strong innate and adaptive immune responses. For clinical application, it is necessary to exploit a Listeria platform strain that is safe and that also retains its immunogenicity to develop vaccine candidates against cancer. In this study, a highly attenuated strain with a deletion of actA/plcB was employed as a vector to deliver the human papillomavirus type 16 (HPV16) E7 antigen, which was stably inserted into the chromosome of L. monocytogenes. The prophylactic and therapeutic efficacy of the recombinant L. monocytogenes strain expressing E7 (LM1-2-E7) were evaluated in C57BL/6 mice. In prophylactic tumor challenge assays, immunization with the recombinant strain LM1-2-E7 was able to protect against tumor formation in 87.5% of the mice, even after a second challenge, suggesting that this prophylactic immunization can provide long-lasting immunity. In the therapeutic setting, immunization with LM1-2-E7 led to tumor regression in 50% of the mice and suppressed tumor growth in the remaining mice. The results showed that the recombinant strain was cleared by the immune system within 5 days after immunization and induced a Th1 immune response against E7 peptide and E7-specific cytotoxic T-lymphocyte (CTL) killing activity without severe inflammatory responses in the spleen and liver. Markedly, recombinant Listeria strain resulted in preferential accumulation within tumor tissues and induced higher numbers of CD8+ T cells that infiltrated into the tumor, which were associated with retardation of tumor growth. Collectively, these data indicate that LM1-2-E7 is a possible vaccine candidate against cervical cancer. PMID:23027427

Jia, Yanyan; Yin, Yuelan; Duan, Feifei; Fu, Hong; Hu, Maozhi; Gao, Yunfei; Pan, Zhiming; Jiao, Xinan

2012-09-20

208

Adenoviral oncoprotein E1B55K mediates colocalization of SSBP2 and PML in response to stress  

PubMed Central

Transient expression of adenoviral oncoprotein E1B55K in normal cells induces aggresome formation and sequestration of critical host proteins in aggresomes. Our previous studies reported that Sequence Specific Binding Protein 2 (SSBP2), a candidate tumor suppressor is recruited to aggresomes in adenovirally transformed human embryonal kidney 293 (HEK293) cells. To understand the extent and significance of the E1B55K-SSBP2 interactions in these cells, we have examined SSBP2 localization under conditions of stress in HEK293 cells. SSBP2 localizes to PML- Nuclear Bodies (PML-NBs) in response to inhibition of nuclear export, treatment with etoposide, hydroxyurea or gamma irradiation only in HEK293 cells. Furthermore, the PML-NBs grow in size and number in response to radiation over a 24 hour period in HEK293 cells analogous to previous findings for other cell types. Nonetheless, we conclude that E1B55K subverts SSBP2 function in HEK293 cells. These findings demonstrate the limitations in using HEK293 cells to study DNA damage response and other cellular processes since SSBP2 and similar regulatory proteins are aberrantly localized due to constitutive E1B55K expression.

2010-01-01

209

Activation of MEK-1 and SEK-1 by Tpl-2 proto-oncoprotein, a novel MAP kinase kinase kinase.  

PubMed Central

The Tpl-2 protein serine/threonine kinase was originally identified, in a C-terminally deleted form, as the product of an oncogene associated with the progression of Moloney murine leukemia virus-induced T cell lymphomas in rats. The kinase domain of Tpl-2 is homologous to the Saccharomyces cerevisiae gene product, STE11, which encodes a MAP kinase kinase kinase. This suggested that Tpl-2 might have a similar activity. Consistent with this hypothesis, immunoprecipitated Tpl-2 and Tpl-2deltaC (a C-terminally truncated mutant) phosphorylated and activated recombinant fusion proteins of the mammalian MAP kinase kinases, MEK-1 and SEK-1, in vitro. Furthermore, transfection of Tpl-2 into COS-1 cells or Jurkat T cells. markedly activated the MAP kinases, ERK-1 and SAP kinase (JNK), which are substrates for MEK-1 and SEK-1, respectively. Tpl-2, therefore, is a MAP kinase kinase kinase which can activate two MAP kinase pathways. After Raf and Mos, Tpl-2 is the third serine/threonine oncoprotein kinase that has been shown to function as a direct activator of MEK-1. Images

Salmeron, A; Ahmad, T B; Carlile, G W; Pappin, D; Narsimhan, R P; Ley, S C

1996-01-01

210

Inhibition of HPV16 E6\\/E7 Immortalization of Normal Keratinocytes by Hairpin Ribozymes  

Microsoft Academic Search

HPV-16 E6 and E7 genes are required to efficiently immortalize a broad spectrum of cell types including cervical keratinocytes. Therefore, the E6\\/E7 genes can be considered relevant targets for anti-cancer therapy. We produced several engineered hairpin (HP) ribozymes to specifically disrupt HPV-16 E6\\/E7 mRNA. After extensive biochemical characterization, one anti-E6 HP ribozyme (R434) was selected for in vivo testing because

Luis M. Alvarez-Salas; Amy E. Cullinan; Andrew Siwkowski; Arnold Hampel; Joseph A. Dipaolo

1998-01-01

211

Efficacy of TRAIL treatment against HPV16 infected cervical cancer cells undergoing senescence following siRNA knockdown of E6/E7 genes.  

PubMed

In this study we investigated E6 and E7 oncogenes from the Human Papilloma Virus as targets for siRNA knockdown in order to boost the efficacy of the anti-cancer drug 'tumor necrosis factor-related apoptosis inducing ligand' (TRAIL). SiHa cells were treated with TRAIL following transfection with E6/E7 siRNA and the expression of death receptors DR4 and DR5, cell viability, apoptosis, senescence and cell cycle analysis were undertaken using flow cytometry, MTT viability assay and cellular ?-galactosidase activity assays. E6/E7 siRNA resulted in significant upregulation of death receptors DR4 and DR5 but did not result in an enhanced sensitivity to TRAIL. Our results indicate that E6/E7-siRNA induces senescence rather than apoptosis in SiHa cells. The occurrence of senescence in drug resistant cervical cancer cells such as the SiHa cell line by E6/E7 siRNA, among other factors, may prevent TRAIL induced activation of extrinsic and intrinsic pathways that lead to apoptotic cell death. Our findings are significant for combinatorial strategies for cancer therapy since the induction of senescence can preclude apoptosis rendering cells to be recalcitrant to TRAIL treatment. PMID:21167816

Eaton, Seron; Wiktor, Peter; Thirstrup, Derek; Lake, Douglas; Nagaraj, Vinay Janthakahalli

2010-12-16

212

Type-Specific Human Papillomavirus E6/E7 mRNA Detection by Real-Time PCR Improves Identification of Cervical Neoplasia ?  

PubMed Central

DNA-based human papillomavirus (HPV) assays show high sensitivity but poor specificity in detecting high-grade cervical lesions. Assays detecting mRNA of the oncoproteins E6 and E7 show higher specificity but lack either detection of all high-risk HPV genotypes or the capacity to specify the detected genotypes. Therefore, a real-time PCR assay detecting type-specific E6/E7 mRNA was developed and the clinical performance evaluated. A total of 210 cervical LBC (liquid-based cytology) samples from 204 women were analyzed for HPV DNA and mRNA with the in-house real-time PCR as well as PreTect HPV-Proofer. The sensitivity of real-time PCR mRNA detection to identify histologically confirmed CIN2+ (cervical intraepithelial neoplasia, grade 2 or higher) was 0.91, compared to 0.95 for DNA analysis. The specificity was 0.68 compared to 0.38, and the positive predictive value (PPV) was higher for mRNA (0.67 versus 0.52) without any loss in negative predictive value (NPV). The sensitivity of the real-time PCR mRNA test was somewhat higher than that for PreTect HPV-Proofer (0.83 versus 0.75) in analyses for the same genotypes. The specificities were similar (0.76 versus 0.77). In analyses for mRNA of the eight most common genotypes in cervical cancer (HPV16, -18, -31, -33, -35, -45, -52, and -58), the sensitivity of detection of CIN2+ lesions was 0.87 and the specificity 0.74, with a PPV of 0.70. In conclusion, real-time PCR for detection of HPV E6/E7 mRNA transcripts can be a sensitive and specific tool in screening and investigation of cervical neoplasia. The composition of HPV types in mRNA testing needs to be further investigated to optimize sensitivity and specificity.

Andersson, Elin; Karrberg, Cecilia; Radberg, Thomas; Blomqvist, Lennart; Zetterqvist, Britt-Marie; Ryd, Walter; Lindh, Magnus; Horal, Peter

2011-01-01

213

E7 proteins from high- and low-risk human papillomaviruses bind to TGF-beta-regulated Smad proteins and inhibit their transcriptional activity.  

PubMed

Human papillomaviruses (HPV) infect keratinocytes of skin and mucosa. Persistent infection can lead to the formation of benign tumors. In cases of high-risk HPV, such as HPV16 or 18, these may further progress to cancer. In order to support viral replication in suprabasal keratinocytes, the HPV E7 protein employs various strategies to keep keratinocytes in cycle and counteracts anti-proliferative signals from outside. HPV16 E7 can directly interfere with transforming growth factor-beta (TGF-beta) signalling by binding to Smad proteins mediating growth arrest. It has been speculated that this property of HPV16 E7 contributes to HPV-associated carcinogenesis. Here, we show that E7 proteins from different low- and high-risk HPV types bind to Smad 1 to 4. The E7 protein from HPV1, a low-risk HPV causing plantar warts, efficiently inhibited Smad 3-induced transcription. Our data strongly indicate that the Smad-binding capacity of E7 proteins from different HPVs may preserve keratinocyte proliferation required for the productive viral life cycle rather than promoting carcinogenesis. PMID:16710631

Habig, M; Smola, H; Dole, V S; Derynck, R; Pfister, H; Smola-Hess, S

2006-05-19

214

Identification and characterization of mechanism of action of P61-E7, a novel phosphine catalysis-based inhibitor of geranylgeranyltransferase-I.  

PubMed

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 p21(CIP1/WAF1) level in human cancer cells. P61-E7 also increases p27(Kip1) protein level and inhibits phosphorylation of p27(Kip1) 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 p21(CIP1/WAF1) and p27(Kip1) 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

2011-10-18

215

A novel fusion protein-based vaccine comprising a cell penetrating and immunostimulatory peptide linked to human papillomavirus (HPV) type 16 E7 antigen generates potent immunologic and anti-tumor responses in mice.  

PubMed

The ultimate success of cancer vaccination is dependent upon the generation of tumor-specific CTLs. In this study, we designed and evaluated a novel fusion protein comprising a cell penetrating and immunostimulatory peptide corresponding to residues 32-51 of the Limulus polyphemus protein (LALF(32-51)) linked to human papillomavirus (HPV) 16 E7 antigen (LALF(32-51)-E7). We demonstrated that LALF(32-51) penetrates the cell membrane and delivers E7 into cells. In a preclinical model of HPV16-induced cervical carcinoma we showed that vaccination with adjuvant-free LALF(32-51)-E7 fusion protein significantly improves the presentation of E7-derived peptides to T-cells in vitro and induces suppression of tumor growth. PMID:21145912

Granadillo, Milaid; Vallespi, Maribel G; Batte, Aileen; Mendoza, Osmany; Soria, Yordanka; Lugo, Victoria M; Torrens, Isis

2010-12-09

216

Combined E7-dendritic cell-based immunotherapy and human sodium/iodide symporter radioiodine gene therapy with monitoring of antitumor effects by bioluminescent imaging in a mouse model of uterine cervical cancer.  

PubMed

Using a uterine cervical cancer cell line expressing human papillomavirus (HPV) 16 E7 antigen and bioluminescent imaging (BLI), we evaluated the therapeutic potential of combined immunotherapy using transfected dendritic cells (DC-E7) and human sodium/iodide symporter (hNIS) radioiodine gene therapy in a xenograft animal cancer model. Dendritic cells expressing either E7 antigen (DC-E7) or no-insert (DC-no insert) were made for immunization materials, and murine uterine cervical cancer cell line coexpressing E7, firefly luciferase, hNIS, and EGFP genes (TC-1/FNG) were prepared for the animal tumor model. C57BL/6 mice were divided into five therapy groups (phosphate-buffered saline [PBS], DC-no insert, DC-E7, I-131, and DC-E7+I-131 groups). Single therapy with either DC-E7 or I-131 induced greater retardation in tumor growth compared with PBS or DC-no insert groups, and it resulted in some tumor-free mice (DC-E7 and I-131 groups, 40% and 20%, respectively). Combination therapy with DC-E7 and I-131 dramatically inhibited tumor growth, thus causing complete disappearance of tumors in all mice, and these effects were further confirmed by BLI in vivo. In conclusion, complete disappearance of the tumor was achieved with combined DC-E7 vaccination and hNIS radioiodine gene therapy in a mouse model with E7-expressing uterine cervical cancer, and serial BLIs successfully demonstrated antitumor effects in vivo. PMID:22091632

Jeon, Yong Hyun; Lee, Ho Won; Lee, You La; Kim, Jung Eun; Hwang, Mi-Hye; Jeong, Shin Young; Lee, Sang-Woo; Ahn, Byeong-Cheol; Ha, Jeoung-Hee; Lee, Jaetae

2011-11-17

217

Rare peptide segments are found significantly more often in proto-oncoproteins than control proteins: implications for immunology and oncology  

PubMed Central

There is some evidence to suggest that peptide segments that are found rarely or never in the host proteome play a role in the immune response to disease-related proteins, both those derived from microbes and those derived from the host itself. We conjecture that this pattern may extend to human proto-oncoproteins. Our hypothesis in this study is that the frequency of rare peptide segments in sets of human proto-oncoproteins is significantly higher than in sets of control proteins, and we show that this is the case. Possible immunological implications of this observation are discussed.

Trost, Brett; Kanduc, Darja; Kusalik, Anthony

2008-01-01

218

HPV E7 expression in skeletal muscle cells distinguishes initiation of the postmitotic state from its maintenance  

Microsoft Academic Search

The E7 oncogene is an essential tool used by papillomaviruses to interfere with the cell cycle and cellular differentiation. We investigated the effects of E7 expression on both cellular functions in skeletal muscle cells, a terminally differentiating system. When expressed in myoblasts, E7 impaired differentiation only partially, but allowed continuation of DNA synthesis during and after differentiation. Surprisingly, E7 expression

Alessandra Sacco; Francesca Siepi; Marco Crescenzi

2003-01-01

219

Induction of robust cellular immunity against HPV6 and HPV11 in mice by DNA vaccine encoding for E6/E7 antigen  

PubMed Central

Due to the strong relationship between the Human Papillomavirus (HPV) “high-risk” subtypes and cervical cancers, most HPV-related studies have been focusing on the “high-risk” HPV subtypes 16 and 18. However, it has been suggested that the “low-risk” subtypes of HPV, HPV6 and HPV11, are the major cause of recurrent respiratory papillomatosis and genital warts. In addition, HPV 6 and 11 are also associated with otolaryngologic malignancies, carcinoma of the lung, tonsil, larynx and low-grade cervical lesions. Therefore, development of HPV therapeutic vaccines targeting on subtypes 6 and 11 E6 or E7 are in great need. In this report, we describe two novel engineered DNA vaccines that encode HPV 6 and 11 consensus E6/E7 fusion proteins (p6E6E7 and p11E6E7) by utilizing a multi-phase strategy. Briefly, after generating consensus sequences, several modifications were performed to increase the expression of both constructs, including codon/RNA optimization, addition of a Kozak sequence and a highly efficient leader sequence. An endoproteolytic cleavage site was also introduced between E6 and E7 protein for proper protein folding and for better CTL processing. The expressions of both constructs were confirmed by western blot analysis and immunofluorescence assay. Vaccination with these DNA vaccines could elicit robust cellular immune responses. The epitope mapping assay was performed to further characterize the cellular immune responses induced by p6E6E7 and p11E6E7. The HPV 6 and 11 E6 or E7-specific immunodominant and subdominant epitopes were verified, respectively. The intracellular cytokine staining revealed that the magnitude of IFN-? and TNF-? secretion in antigen-specific CD8+ cells was significantly enhanced, indicating that the immune responses elicited by p6E6E7 and p11E6E7 was heavily skewed toward driving CD8+ T cells. Such DNA immunogens are interesting candidates for further studies on HPV 6 and 11-associated diseases.

Shin, Thomas; Pankhong, Panyupa; Yan, Jian; Khan, Amir S.; Sardesai, Niranjan Y.; Weiner, David B.

2012-01-01

220

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.

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

2001-01-01

221

A family of transcriptional adaptor proteins targeted by the E1A oncoprotein.  

PubMed

The cellular protein p300 is a target of the adenoviral E1A oncoprotein and is thought to participate in preventing the G0/G1 transition in the cell cycle, activating certain enhancers and stimulating differentiation pathways. CBP is a protein that is associated with and coactivates the transcription factor CREB, mediating the induction by cyclic AMP of certain responsive promoters. The sequences of p300 and CBP are highly related. We show here that p300, like CBP2, can stimulate transcription. This activity is directly and specifically inhibited by E1A. We also find that CBP exists in a DNA-bound complex containing a member of the CREB family and that E1A and CBP interact with one another in vivo. In keeping with the idea that E1A functionally targets CBP, cAMP-dependent transcription is repressed by E1A. Thus, p300 and CBP define a family of transcriptional adaptor proteins that are specifically targeted by the E1A oncoprotein. PMID:7870178

Arany, Z; Newsome, D; Oldread, E; Livingston, D M; Eckner, R

1995-03-01

222

Human T-cell leukemia virus type-1 Tax oncoprotein regulates G-protein signaling  

PubMed Central

Human T-cell leukemia virus type-1 (HTLV-1) is associated with adult T-cell leukemia (ATL) and neurological syndromes. HTLV-1 encodes the oncoprotein Tax-1, which modulates viral and cellular gene expression leading to T-cell transformation. Guanine nucleotide–binding proteins (G proteins) and G protein–coupled receptors (GPCRs) constitute the largest family of membrane proteins known and are involved in the regulation of most biological functions. Here, we report an interaction between HTLV-1 Tax oncoprotein and the G-protein ? subunit. Interestingly, though the G-protein ? subunit inhibits Tax-mediated viral transcription, Tax-1 perturbs G-protein ? subcellular localization. Functional evidence for these observations was obtained using conditional Tax-1–expressing transformed T-lymphocytes, where Tax expression correlated with activation of the SDF-1/CXCR4 axis. Our data indicated that HTLV-1 developed a strategy based on the activation of the SDF-1/CXCR4 axis in the infected cell; this could have tremendous implications for new therapeutic strategies.

Twizere, Jean-Claude; Springael, Jean-Yves; Boxus, Mathieu; Burny, Arsene; Dequiedt, Franck; Dewulf, Jean-Francois; Duchateau, Julie; Portetelle, Daniel; Urbain, Patrice; Lint, Carine Van; Green, Patrick L.; Mahieux, Renaud; Parmentier, Marc; Willems, Luc; Kettmann, Richard

2007-01-01

223

Human T-cell leukemia virus type-1 Tax oncoprotein regulates G-protein signaling.  

PubMed

Human T-cell leukemia virus type-1 (HTLV-1) is associated with adult T-cell leukemia (ATL) and neurological syndromes. HTLV-1 encodes the oncoprotein Tax-1, which modulates viral and cellular gene expression leading to T-cell transformation. Guanine nucleotide-binding proteins (G proteins) and G protein-coupled receptors (GPCRs) constitute the largest family of membrane proteins known and are involved in the regulation of most biological functions. Here, we report an interaction between HTLV-1 Tax oncoprotein and the G-protein beta subunit. Interestingly, though the G-protein beta subunit inhibits Tax-mediated viral transcription, Tax-1 perturbs G-protein beta subcellular localization. Functional evidence for these observations was obtained using conditional Tax-1-expressing transformed T-lymphocytes, where Tax expression correlated with activation of the SDF-1/CXCR4 axis. Our data indicated that HTLV-1 developed a strategy based on the activation of the SDF-1/CXCR4 axis in the infected cell; this could have tremendous implications for new therapeutic strategies. PMID:16990599

Twizere, Jean-Claude; Springael, Jean-Yves; Boxus, Mathieu; Burny, Arsène; Dequiedt, Franck; Dewulf, Jean-François; Duchateau, Julie; Portetelle, Daniel; Urbain, Patrice; Van Lint, Carine; Green, Patrick L; Mahieux, Renaud; Parmentier, Marc; Willems, Luc; Kettmann, Richard

2006-09-21

224

Arginine methylation controls the subcellular localization and functions of the oncoprotein splicing factor SF2/ASF.  

PubMed

Alternative splicing and posttranslational modifications (PTMs) are major sources of protein diversity in eukaryotic proteomes. The SR protein SF2/ASF is an oncoprotein that functions in pre-mRNA splicing, with additional roles in other posttranscriptional and translational events. Functional studies of SR protein PTMs have focused exclusively on the reversible phosphorylation of Ser residues in the C-terminal RS domain. We confirmed that human SF2/ASF is methylated at residues R93, R97, and R109, which were identified in a global proteomic analysis of Arg methylation, and further investigated whether these methylated residues regulate the properties of SF2/ASF. We show that the three arginines additively control the subcellular localization of SF2/ASF and that both the positive charge and the methylation state are important. Mutations that block methylation and remove the positive charge result in the cytoplasmic accumulation of SF2/ASF. The consequent decrease in nuclear SF2/ASF levels prevents it from modulating the alternative splicing of target genes, results in higher translation stimulation, and abrogates the enhancement of nonsense-mediated mRNA decay. This study addresses the mechanisms by which Arg methylation and the associated positive charge regulate the activities of SF2/ASF and emphasizes the significance of localization control for an oncoprotein with multiple functions in different cellular compartments. PMID:20308322

Sinha, Rahul; Allemand, Eric; Zhang, Zuo; Karni, Rotem; Myers, Michael P; Krainer, Adrian R

2010-03-22

225

Homodimerization of the Meq Viral Oncoprotein Is Necessary for Induction of T-Cell Lymphoma by Marek's Disease Virus ?  

PubMed Central

Marek's disease virus (MDV) is a lymphotropic alphaherpesvirus that induces fatal rapid-onset T-cell lymphomas in chickens, its natural host. The MDV-encoded nuclear oncoprotein Meq is essential for lymphomagenesis and acts as a regulator of transcription. Meq has structural features, including a basic domain adjacent to a leucine zipper motif (B-ZIP), that suggest it is related to the Jun/Fos family of transcription factors. Via the leucine zipper, Meq can form homodimers or heterodimerize with c-Jun. Meq/Meq homodimers are associated with transrepression, and Meq/Jun heterodimers can transactivate target genes carrying an AP-1-like binding site. In order to determine the role of the leucine zipper and of Meq dimerization in T lymphomagenesis, specific point mutations were engineered into the highly oncogenic RB-1B strain of MDV to produce virus completely lacking a functional Meq leucine zipper (RB-1B MeqBZIP/BZIP) or virus encoding Meq that cannot homodimerize but can still bind to c-Jun and an AP-1-like site on DNA (RB-1B MeqHom/Hom). Both of these mutant viruses were capable of replication in cultured chicken embryo fibroblasts. However both mutations resulted in a complete loss of oncogenicity, since no lymphomas were produced up to 90 days postinfection in experimentally infected chicks. We conclude that the leucine zipper is necessary for the oncogenic activity of Meq and/or the efficient establishment of long-term MDV latency in T cells. Moreover, it appears that the ability to form homodimers is an absolute requirement and the ability to bind c-Jun alone is insufficient for the T-cell lymphomagenesis associated with virulent MDV.

Brown, Andrew C.; Smith, Lorraine P.; Kgosana, Lydia; Baigent, Susan J.; Nair, Venugopal; Allday, Martin J.

2009-01-01

226

Expression of the Stress Response Oncoprotein LEDGF/p75 in Human Cancer: A Study of 21 Tumor Types  

PubMed Central

Oxidative stress-modulated signaling pathways have been implicated in carcinogenesis and therapy resistance. The lens epithelium derived growth factor p75 (LEDGF/p75) is a transcription co-activator that promotes resistance to stress-induced cell death. This protein has been implicated in inflammatory and autoimmune conditions, HIV-AIDS, and cancer. Although LEDGF/p75 is emerging as a stress survival oncoprotein, there is scarce information on its expression in human tumors. The present study was performed to evaluate its expression in a comprehensive panel of human cancers. Transcript expression was examined in the Oncomine cancer gene microarray database and in a TissueScan Cancer Survey Panel quantitative polymerase chain reaction (Q-PCR) array. Protein expression was assessed by immunohistochemistry (IHC) in cancer tissue microarrays (TMAs) containing 1735 tissues representing single or replicate cores from 1220 individual cases (985 tumor and 235 normal tissues). A total of 21 major cancer types were analyzed. Analysis of LEDGF/p75 transcript expression in Oncomine datasets revealed significant upregulation (tumor vs. normal) in 15 out of 17 tumor types. The TissueScan Cancer Q-PCR array revealed significantly elevated LEDGF/p75 transcript expression in prostate, colon, thyroid, and breast cancers. IHC analysis of TMAs revealed significant increased levels of LEDGF/p75 protein in prostate, colon, thyroid, liver and uterine tumors, relative to corresponding normal tissues. Elevated transcript or protein expression of LEDGF/p75 was observed in several tumor types. These results further establish LEDGF/p75 as a cancer-related protein, and provide a rationale for ongoing studies aimed at understanding the clinical significance of its expression in specific human cancers.

Basu, Anamika; Rojas, Heather; Banerjee, Hiya; Cabrera, Irena B.; Perez, Kayla Y.; De Leon, Marino; Casiano, Carlos A.

2012-01-01

227

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

Code of Federal Regulations, 2012 CFR

...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 awards?...

2012-10-01

228

Human Papillomavirus Type 16 Nucleoprotein E7 is a Tumor Rejection Antigen  

Microsoft Academic Search

It has been speculated that immunological mechanisms play an important role in the control of carcinomas associated with human papillomavirus (HPV), such as cervical cancers. We have now demonstrated that immunization of C3H\\/HeN mice by syngeneic nontumorigenic fibroblast-like cells that contain the transfected HPV-16 E7 gene conferred protection against transplanted cells from a HPV-16 E7-positive syngeneic tumor. This protection was

Lieping Chen; Elaine Kinney Thomas; Shiu-Lok Hu; Ingegerd Hellstrom; Karl Erik Hellstrom

1991-01-01

229

Methyl jasmonate reduces the survival of cervical cancer cells and downregulates HPV E6 and E7, and survivin.  

PubMed

The present study further investigated the mode of action of methyl jasmonate (MJ) in different cervical cancer cell lines. We show that in addition to the short term cytotoxicity, MJ effectively reduced the survival of cervical cancer cells (clonogenicity assays). MJ induced apoptosis in all cervical cancer cells. In some cell lines, MJ caused elevation of the mitochondrial superoxide anion, notably, in HeLa and CaSki. Changes in the expression of p53 and bax were variable, yet, downregulation of survivin was common to all cervical cancer cells. MJ significantly reduced the levels of the human papillomavirus (HPV) E6 and E7 proteins without alteration of the mRNA levels. Moreover, ectopic expression of E6, E7 or both in cervical cancer cells that lack HPV (C33A), did not alter significantly their response to MJ. Our studies point to MJ as an effective anticancer agent against a variety of cervical cancer cells acting through shared and different pathways to induce cell death regardless of the presence of HPV. PMID:22198483

Milrot, Elad; Jackman, Anna; Kniazhanski, Tatiana; Gonen, Pinhas; Flescher, Eliezer; Sherman, Levana

2011-12-23

230

RNA (E6 and E7) Assays versus DNA (E6 and E7) Assays for Risk Evaluation for Women Infected with Human Papillomavirus?  

PubMed Central

In the majority of cases, high-risk human papillomavirus (HR HPV) infections regress spontaneously, with only a small percentage progressing to high-grade lesions. Current screening methods are based on DNA detection. An alternative would be to monitor expression of the E6 and E7 viral oncogenes continuously expressed by malignant phenotypes. In the work reported in this paper, we compared the two methods for a group of women with high-risk HPV infections. Cervical specimens from 400 women, previously found to be HPV DNA positive, were analyzed for HPV DNA by a liquid hybridization assay and typed by multiplex PCR (for types 16, 18, 31, and 33). Identification of HR HPV E6 and E7 RNA transcripts was performed using real-time reverse transcription-PCR and nucleic acid sequence-based amplification assays. Results were compared with concurrent cytological data. HR HPVs were found in 61.2% of patients. The most common genotype was HPV type 16 (HPV-16) (47.1%), followed by HPV-18, HPV-31, and HPV-33. Nine percent of cases involved other genotypes. Among 223 HPV DNA-positive samples, only 118 were positive in the RNA test. Among HPV DNA-positive patients with normal cytology, we detected E6 and E7 RNA transcripts in two cases (18.2%). The rate of detection increased gradually with the grade of the observed lesions, rising from 20% for patients with atypical squamous cells of undetermined significance to 48.1% for women with low-grade squamous intraepithelial lesions and 86.3% for those with high-grade squamous intraepithelial lesions. These results suggest that testing for HPV E6 and E7 transcripts could be a useful tool for screening and patient management, providing more accurate predictions of risk than those obtained by DNA testing.

Cattani, Paola; Siddu, Alessia; D'Onghia, Sara; Marchetti, Simona; Santangelo, Rosaria; Vellone, Valerio G.; Zannoni, Gian Franco; Fadda, Giovanni

2009-01-01

231

COX-2/PGE2: molecular ambassadors of Kaposi's sarcoma-associated herpes virus oncoprotein-v-FLIP  

PubMed Central

Kaposi's sarcoma herpesvirus (KSHV) latent oncoprotein viral FLICE (FADD-like interferon converting enzyme)-like inhibitory protein (v-FLIP) or K13, a potent activator of NF-?B, has well-established roles in KSHV latency and oncogenesis. KSHV-induced COX-2 represents a novel strategy employed by KSHV to promote latency and inflammation/angiogenesis/invasion. Here, we demonstrate that v-FLIP/K13 promotes tumorigenic effects via the induction of host protein COX-2 and its inflammatory metabolite PGE2 in an NF-?B-dependent manner. In addition to our previous studies demonstrating COX-2/PGE2's role in transcriptional regulation of KSHV latency promoter and latent gene expression, the current study adds to the complexity that though LANA-1 (latency associated nuclear antigen) is utilizing COX-2/PGE2 as critical factors for its transcriptional regulation, it is the v-FLIP/K13 gene in the KSHV latency cluster that maintains continuous COX-2/PGE2 levels in the infected cells. We demonstrate that COX-2 inhibition, via its chemical inhibitors (NS-398 or celecoxib), reduced v-FLIP/K13-mediated NF-?B induction, and extracellular matrix (ECM) interaction-mediated signaling, mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) levels, and subsequently downregulated detachment-induced apoptosis (anoikis) resistance. vFLIP expression mediated the secretion of cytokines, and spindle cell differentiation activated the phosphorylation of p38, RSK, FAK, Src, Akt and Rac1-GTPase. The COX-2 inhibition in v-FLIP/K13-HMVECs reduced inflammation and invasion/metastasis-related genes, along with reduced anchorage-independent colony formation via modulating ‘extrinsic' as well as ‘intrinsic' cell death pathways. COX-2 blockade in v-FLIP/K13-HMVEC cells drastically augmented cell death induced by removal of essential growth/survival factors secreted in the microenvironment. Transformed cells obtained from anchorage-independent colonies of COX-2 inhibitor-treated v-FLIP/K13-HMVEC cells expressed lower levels of endothelial–mesenchymal transition genes such as slug, snail and twist, and higher expression of the tumor-suppressor gene, E-cadherin. Taken together, our study provides strong evidences that FDA-approved COX-2 inhibitors have great potential in blocking tumorigenic events linked to KSHV's oncogenic protein v-FLIP/K13.

Sharma-Walia, N; Patel, K; Chandran, K; Marginean, A; Bottero, V; Kerur, N; Paul, A G

2012-01-01

232

Mice Expressing the E7 Oncogene of HPV16 in Epithelium Show Central Tolerance, and Evidence of Peripheral Anergising Tolerance, to E7Encoded Cytotoxic T-Lymphocyte Epitopes  

Microsoft Academic Search

In order to derive mice which expressed both the E7 open reading frame transgene of human papillomavirus type 16 in skin and MHC class 1 restriction elements for several E7-encoded cytotoxic T-lymphocyte (CTL) epitopes, K14.HPV16E7 mice which express E7 in basal keratinocytes were crossed to the F1 generation with A2.1 Kbtransgenic mice which express the MHC binding cleft domains of

Tracy Doan; Melita Chambers; Michael Street; Karen Herd; Paul Lambert; Robert Tindle

1998-01-01

233

High Incidence of HPV-Associated Head and Neck Cancers in FA Deficient Mice Is Associated with E7's Induction of DNA Damage through Its Inactivation of Pocket Proteins.  

PubMed

Fanconi anemia (FA) patients are highly susceptible to solid tumors at multiple anatomical sites including head and neck region. A subset of head and neck cancers (HNCs) is associated with 'high-risk' HPVs, particularly HPV16. However, the correlation between HPV oncogenes and cancers in FA patients is still unclear. We previously learned that FA deficiency in mice predisposes HPV16 E7 transgenic mice to HNCs. To address HPV16 E6's oncogenic potential under FA deficiency in HNCs, we utilized HPV16 E6-transgenic mice (K14E6) and HPV16 E6/E7-bi-transgenic mice (K14E6E7) on genetic backgrounds sufficient or deficient for one of the fanc genes, fancD2 and monitored their susceptibility to HNCs. K14E6 mice failed to develop tumor. However, E6 and fancD2-deficiency accelerated E7-driven tumor development in K14E6E7 mice. The increased tumor incidence was more correlated with E7-driven DNA damage than proliferation. We also found that deficiency of pocket proteins, pRb, p107, and p130 that are well-established targets of E7, could recapitulate E7's induction of DNA damage. Our findings support the hypothesis that E7 induces HPV-associated HNCs by promoting DNA damage through the inactivation of pocket proteins, which explains why a deficiency in DNA damage repair would increase susceptibility to E7-driven cancer. Our results further demonstrate the unexpected finding that FA deficiency does not predispose E6 transgenic mice to HNCs, indicating a specificity in the synergy between FA deficiency and HPV oncogenes in causing HNCs. PMID:24086435

Park, Jung Wook; Shin, Myeong-Kyun; Pitot, Henry C; Lambert, Paul F

2013-09-23

234

High Incidence of HPV-Associated Head and Neck Cancers in FA Deficient Mice Is Associated with E7's Induction of DNA Damage through Its Inactivation of Pocket Proteins  

PubMed Central

Fanconi anemia (FA) patients are highly susceptible to solid tumors at multiple anatomical sites including head and neck region. A subset of head and neck cancers (HNCs) is associated with ‘high-risk’ HPVs, particularly HPV16. However, the correlation between HPV oncogenes and cancers in FA patients is still unclear. We previously learned that FA deficiency in mice predisposes HPV16 E7 transgenic mice to HNCs. To address HPV16 E6’s oncogenic potential under FA deficiency in HNCs, we utilized HPV16 E6-transgenic mice (K14E6) and HPV16 E6/E7-bi-transgenic mice (K14E6E7) on genetic backgrounds sufficient or deficient for one of the fanc genes, fancD2 and monitored their susceptibility to HNCs. K14E6 mice failed to develop tumor. However, E6 and fancD2-deficiency accelerated E7-driven tumor development in K14E6E7 mice. The increased tumor incidence was more correlated with E7-driven DNA damage than proliferation. We also found that deficiency of pocket proteins, pRb, p107, and p130 that are well-established targets of E7, could recapitulate E7’s induction of DNA damage. Our findings support the hypothesis that E7 induces HPV-associated HNCs by promoting DNA damage through the inactivation of pocket proteins, which explains why a deficiency in DNA damage repair would increase susceptibility to E7-driven cancer. Our results further demonstrate the unexpected finding that FA deficiency does not predispose E6 transgenic mice to HNCs, indicating a specificity in the synergy between FA deficiency and HPV oncogenes in causing HNCs.

Park, Jung Wook; Shin, Myeong-Kyun; Pitot, Henry C.; Lambert, Paul F.

2013-01-01

235

Suspected leukemia oncoproteins CREB1 and LYL1 regulate Op18/STMN1 expression.  

PubMed

Stathmin (STMN1) is a microtubule destabilizing protein with a key role in cell cycle progression and cell migration that is up-regulated in several cancers and may contribute to the malignant phenotype. However, the factors that regulate its expression are not well understood. Loss as well as gain-of-function p53 mutations up-regulate STMN1 and in acute myelogenous leukemia where p53 is predominantly wild-type, STMN1 is also over-expressed. Here we show regulatory control of STMN1 expression by the leucine zipper transcription factor (TF) CREB1 and the basic helix-loop-helix TF LYL1. By ChIP-chip experiments we demonstrate in vivo the presence of LYL1 and CREB1 in close proximity on the STMN1 promoter and using promoter assays we reveal co-regulation of STMN1 by CREB1 and LYL1. By contrast, TAL1, another suspected oncoprotein in leukemia and close relative of LYL1, exerts no regulatory effect on the STMN1 promoter. NLI, LMO2 and GATA2 are previously described co-activators of Tal1/Lyl1-E47 transcriptional complexes and potentiate Lyl1 activation of the STMN1 promoter while having no effect on TAL1 transactivation. Promoter mutations that abrogate CREB1 proximal binding or mutations of the DNA-binding domain of CREB1 abolish LYL1 transcriptional activation. These results show that CRE and Ebox sites function as coordinated units and support previous evidence of joint CREB1-and LYL1 transcription events activating an aberrant subset of promoters in leukemia. CREB1 or LYL1 shRNA knock-down down-regulate STMN1 expression. Because down-regulation of STMN1 has been shown to have anti-proliferative effects, while CREB1 and LYL1 are suspected oncoproteins, interference with CREB1-LYL1 interactions may complement standard chemotherapy and yield additional beneficial effects. PMID:23000483

San-Marina, Serban; Han, Youqi; Liu, Jian; Minden, Mark D

2012-09-19

236

Deletion analysis of BMI1 oncoprotein identifies its negative regulatory domain  

PubMed Central

Background The polycomb group (PcG) protein BMI1 is an important regulator of development. Additionally, aberrant expression of BMI1 has been linked to cancer stem cell phenotype and oncogenesis. In particular, its overexpression has been found in several human malignancies including breast cancer. Despite its established role in stem cell maintenance, cancer and development, at present not much is known about the functional domains of BMI1 oncoprotein. In the present study, we carried out a deletion analysis of BMI1 to identify its negative regulatory domain. Results We report that deletion of the C-terminal domain of BMI1, which is rich in proline-serine (PS) residues and previously described as PEST-like domain, increased the stability of BMI1, and promoted its pro-oncogenic activities in human mammary epithelial cells (HMECs). Specifically, overexpression of a PS region deleted mutant of BMI1 increased proliferation of HMECs and promoted an epithelial-mesenchymal transition (EMT) phenotype in the HMECs. Furthermore, when compared to the wild type BMI1, exogenous expression of the mutant BMI1 led to a significant downregulation of p16INK4a and an efficient bypass of cellular senescence in human diploid fibroblasts. Conclusions In summary, our data suggest that the PS domain of BMI1 is involved in its stability and that it negatively regulates function of BMI1 oncoprotein. Our results also suggest that the PS domain of BMI1 could be targeted for the treatment of proliferative disorders such as cancer and aging.

2010-01-01

237

Direct Activation of Cyclin-Dependent Kinase 2 by Human Papillomavirus E7  

PubMed Central

Addition of human papillomavirus (HPV) E7 CDK2/cyclin A or CDK2/cyclin E, purified from either insect cells or bacteria, dramatically upregulates histone H1 kinase activity. Activation is substrate specific, with a smaller effect noted for retinoblastoma protein (Rb). The CDK2 stimulatory activity is equivalent in high-risk (HPV type 16 [HPV16] and HPV31) and low-risk (HPV6b) E7. Mutational analyses of HPV16 E7 indicate that the major activity resides in amino acids 9 to 38, spanning CR1 and CR2, and does not require casein kinase II or Rb-binding domain functions. Synthetic peptides spanning HPV16 amino acid residues 9 to 38 also activate CDK2. Peptides containing this sequence that carry biotin on the carboxy terminus, as well as a photoactivated cross-linking group (benzophenone), also activate the complex and covalently associate with the CDK2/cyclin A complex in a specific manner requiring UV. Cross-linking studies that use protein monomers detect association of the E7 peptides with cyclin A but not CDK2. Together, our results indicate a novel mechanism whereby E7 promotes HPV replication by directly altering CDK2 activity and substrate specificity.

He, Wanxia; Staples, Doug; Smith, Clark; Fisher, Chris

2003-01-01

238

Regression of Established Human Papillomavirus Type 16 (HPV16) Immortalized Tumors In Vivo by Vaccinia Viruses Expressing Different Forms of HPV16 E7 Correlates with Enhanced CD8+ T-Cell Responses That Home to the Tumor Site  

Microsoft Academic Search

Using vaccinia virus as a live vector, we show that the expression of human papillomavirus type 16 (HPV-16) E7 fused to a nonhemolytic portion of the Listeria monocytogenes virulence factor, listeriolysin O (LLO), induces an immune response that causes the regression of established HPV-16 immortalized tumors in C57BL\\/6 mice. The vaccinia virus construct expressing LLO fused to E7 (VacLLOE7) was

ABIGAIL LAMIKANRA; ZHEN-KUN PAN; STUART N. ISAACS; T.-C. Wu; Y. Paterson

2001-01-01

239

Enhanced therapeutic effects conferred by an experimental DNA vaccine targeting human papillomavirus-induced tumors.  

PubMed

Abstract Human papillomavirus (HPV) infection is responsible for all cervical cancer cases, other anogenital cancers, and head and neck tumors. The epidemiological relevance of HPV-induced tumors reinforces the need for the development of therapeutic antitumor vaccines. Clinical trials with different vaccine formulations, particularly DNA vaccines, have provided promising results but have still been unable to achieve the immunogenicity required for use in infected patients. In experimental conditions, anticancer HPV-specific vaccines induced E7-specific CD8(+) T-cell responses but did not confer full therapeutic antitumor protection in mice with transplanted HPV-expressing TC-1 cells, which are the most frequently used nonclinical protection correlate for antitumor effects. Our group has developed a DNA vaccine strategy based on the fusion of HPV oncoproteins to the herpes virus gD protein. This vaccine promoted the induction of antigen-specific cytotoxic CD8(+) T-cell responses and partial antitumor therapeutic effects based on the blockade of coinhibitory signals and the enhancement of coactivation mechanisms. In the present study, we report conditions leading to full therapeutic antitumor effects using the TC-1 cell murine model after a single vaccine dose. The combination of a coadministered plasmid encoding IL-2, optimization of the coding sequence for mammalian cells, and the use of different delivery routes resulted in enhancements of the E7-specific cytotoxic CD8(+) T-cell responses and full therapeutic protection under experimental conditions. The combination of these strategies augmented the potency of the DNA vaccine formulation to levels not previously achieved by other therapeutic antitumor vaccines under similar experimental conditions, including some that have been taken to clinical trials. PMID:24007495

Diniz, Mariana O; Cariri, Francisco A M O; Aps, Luana R M M; Ferreira, Luís C S

2013-10-01

240

Recombinant Adeno-Associated Virus Expressing Human Papillomavirus Type 16 E7 Peptide DNA Fused with Heat Shock Protein DNA as a Potential Vaccine for Cervical Cancer  

Microsoft Academic Search

In this study, we explore a potential vaccine for human papillomavirus (HPV)-induced tumors, using heat shock protein as an adjuvant, a peptide vaccine for safety, and adeno-associated virus (AAV) as a gene delivery vector. The tumor vaccine was devised by constructing a chimeric gene which contained HPV type 16 E7 cytotoxic T-lymphocyte (CTL) epitope DNA (M. C. Feltkamp, H. L.

DAI-WEI LIU; YEOU-PING TSAO; JOHN T. KUNG; YU-AN DING; HUEY-KANG SYTWU; XIAO XIAO; SHOW-LI CHEN

2000-01-01

241

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

242

Antitumor therapeutic and antimetastatic activity of electroporation-delivered human papillomavirus 16 E7 DNA vaccines: a possible mechanism for enhanced tumor control.  

PubMed

DNA vaccines are known to be lacking in immunogenicity in humans. Presently, electroporation (EP) is thought to overcome this limitation. Here, we investigate whether human papillomavirus 16 E7 DNA vaccines delivered by EP might elicit potent antitumor activity in animal cervical cancer models, with a focus on the underlying mechanism(s). Intramuscular (IM)-EP delivery of E7 DNA vaccines induced more potent antitumor therapeutic and antimetastatic activity compared with IM delivery. Moreover, the tumor-controlled animals by IM-EP possessed long-term memory responses to parental tumor cells. This improved antitumor effect was concomitant with augmented Ag-specific CTL activities. IM-EP also induced IgG and Th-cell responses higher than IM delivery. Finally, IM-EP resulted in more antigen production in and more attraction of immune cells into the site of DNA injection, suggesting that these biological and immunological changes made by IM-EP might be responsible for enhanced CTL activities and antitumor resistance. Thus, this study shows that IM-EP can induce more potent antitumor activity by augmenting CTL responses possibly through more antigen production in and more attraction of immune cells into the muscle sites. This study also suggests that IM-EP of E7 DNA vaccines might be a potential approach toward treating patients with cervical cancer. PMID:21649506

Lee, In Hee; Park, Jae-Bok; Cheong, Minseon; Choi, Youn Seok; Park, Daehan; Sin, Jeong-Im

2011-06-07

243

Production of Neutral Heavy Leptons by Neutrinos in the E7 Gauge Model of Weak Interactions.  

National Technical Information Service (NTIS)

An attempt, is made, in the framework of the Guersey-Sikivie gauge model of weak interactions based on the E7 group, to explain the recently observed neutrino-production of a relatively long-lived neutral heavy lepton in SKAT bubble chamber experiment. It...

A. Bottino C. W. Kim

1977-01-01

244

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

2013-08-14

245

Characterization of Human Myocardial Fibroblasts Immortalized by HPV16 E6–E7 Genes  

Microsoft Academic Search

Human myocardial fibroblasts (HMF) have proved to be useful as a species specific cell culture system in various studies on myocarditis and cardiac remodelling. However, their use is limited, since they are hard to obtain and lifespan is short due to replicative senescence. To overcome these disadvantages, we transfected primary HMF with the E6 and E7 genes of the oncogenic

W. Harms; T. Rothämel; K. Miller; G. Harste; M. Grassmann; A. Heim

2001-01-01

246

c-Fos Proto-Oncoprotein Is Degraded by the Proteasome Independently of Its Own Ubiquitinylation In Vivo  

Microsoft Academic Search

Prior ubiquitinylation of the unstable c-Fos proto-oncoprotein is thought to be required for recognition and degradation by the proteasome. Contradicting this view, we report that, although c-Fos can form conjugates with ubiquitin in vivo, nonubiquitinylatable c-Fos mutants show regulated degradation identical to that of the wild-type protein in living cells under two classical conditions of study: transient c-fos gene expression

Guillaume Bossis; Patrizia Ferrara; Claire Acquaviva; Isabelle Jariel-Encontre; Marc Piechaczyk

2003-01-01

247

Human Papillomavirus Type 5 E6 Oncoprotein Represses the Transforming Growth Factor   Signaling Pathway by Binding to SMAD3  

Microsoft Academic Search

Mechanisms of cellular transformation associated with human papillomavirus type 5 (HPV5), which is responsible for skin carcinomas in epidermodysplasia verruciformis (EV) patients, are poorly understood. Using a yeast two-hybrid screening and molecular and cellular biology experiments, we found that HPV5 oncoprotein E6 interacts with SMAD3, a key component in the transforming growth factor 1 (TGF-1) signaling pathway. HPV5 E6 inhibits

Jose-Andres Mendoza; Yves Jacob; Patricia Cassonnet; Michel Favre

2006-01-01

248

RAGE-Dependent Activation of the Oncoprotein Pim1 Plays a Critical Role in Systemic Vascular Remodeling Processes  

PubMed Central

Objective Vascular remodeling diseases (VRD) are mainly characterized by inflammation and a vascular smooth muscle cells (VSMCs) proproliferative and anti-apoptotic phenotype. Recently, the activation of the advanced glycation endproducts receptor (RAGE) has been shown to promote VSMC proliferation and resistance to apoptosis in VRD in a signal transducer and activator of transcription (STAT)3-dependant manner. Interestingly, we previously described in both cancer and VRD that the sustainability of this proproliferative and antiapoptotic phenotype requires activation of the transcription factor NFAT (nuclear factor of activated T-cells). In cancer, NFAT activation is dependent of the oncoprotein provirus integration site for Moloney murine leukemia virus (Pim1), which is regulated by STAT3 and activated in VRD. Therefore, we hypothesized that RAGE/STAT3 activation in VSMC activates Pim1, promoting NFAT and thus VSMC proliferation and resistance to apoptosis. Methods/Results In vitro, freshly isolated human carotid VSMCs exposed to RAGE activator N?-(carboxymethyl)lysine (CML) for 48 hours had (1) activated STAT3 (increased P-STAT3/STAT3 ratio and P-STAT3 nuclear translocation); (2) increased STAT3-dependent Pim1 expression resulting in NFATc1 activation; and (3) increased Pim1/NFAT-dependent VSMC proliferation (PCNA, Ki67) and resistance to mitochondrial-dependent apoptosis (TMRM, Annexin V, TUNEL). Similarly to RAGE inhibition (small interfering RNA [siRNA]), Pim1, STAT3 and NFATc1 inhibition (siRNA) reversed these abnormalities in human carotid VSMC. Moreover, carotid artery VSMCs isolated from Pim1 knockout mice were resistant to CML-induced VSMC proliferation and resistance to apoptosis. In vivo, RAGE inhibition decreases STAT3/Pim1/NFAT activation, reversing vascular remodeling in the rat carotid artery-injured model. Conclusion RAGE activation accounts for many features of VRD including VSMC proliferation and resistance to apoptosis by the activation of STAT3/Pim1/NFAT axis. Molecules aimed to inhibit RAGE could be of a great therapeutic interest for the treatment of VRD.

Meloche, Jolyane; Paulin, Roxane; Courboulin, Audrey; Lambert, Caroline; Barrier, Marjorie; Bonnet, Pierre; Bisserier, Malik; Roy, Melanie; Sussman, Mark A.; Agharazii, Mohsen; Bonnet, Sebastien

2012-01-01

249

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

PubMed Central

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. 1H-NMR results for the rHbICN PheB10Tyr derivative showed chemical shifts of TyrB10 OH? at 31.00ppm, GlnE7 N?1H/N?2H at 10.66ppm/?3.27ppm, and PheE11 C?H at 11.75ppm, indicating the presence of a crowded, collapsed, and constrained distal pocket. Strong dipolar contacts and inter-residues crosspeaks between Gln E7/6-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 hemeligand moiety.

Ramos-Santana, Brenda J.; Lopez-Garriga, Juan

2012-01-01

250

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.

Oteiza, Alexandra; Mechti, Nadir

2011-01-01

251

The MUC1-C Oncoprotein Binds to the BH3 Domain of the Pro-apoptotic BAX Protein and Blocks BAX Function*  

PubMed Central

The pro-apoptotic BAX protein contains a BH3 domain that is necessary for its dimerization and for activation of the intrinsic apoptotic pathway. The MUC1 (mucin 1) heterodimeric protein is overexpressed in diverse human carcinomas and blocks apoptosis in the response to stress. In this study, we demonstrate that the oncogenic MUC1-C subunit associates with BAX in human cancer cells. MUC1-C·BAX complexes are detectable in the cytoplasm and mitochondria and are induced by genotoxic and oxidative stress. The association between MUC1-C and BAX is supported by the demonstration that the MUC1-C cytoplasmic domain is sufficient for the interaction with BAX. The results further show that the MUC1-C cytoplasmic domain CQC motif binds directly to the BAX BH3 domain at Cys-62. Consistent with binding to the BAX BH3 domain, MUC1-C blocked BAX dimerization in response to (i) truncated BID in vitro and (ii) treatment of cancer cells with DNA-damaging agents. In concert with these results, MUC1-C attenuated localization of BAX to mitochondria and the release of cytochrome c. These findings indicate that the MUC1-C oncoprotein binds directly to the BAX BH3 domain and thereby blocks BAX function in activating the mitochondrial death pathway.

Ahmad, Rehan; Alam, Maroof; Rajabi, Hasan; Kufe, Donald

2012-01-01

252

Papilloma formation by cottontail rabbit papillomavirus requires E1 and E2 regulatory genes in addition to E6 and E7 transforming genes.  

PubMed Central

The present study used the cottontail rabbit papillomavirus DNA-rabbit system to evaluate whether the regulatory genes E1 and E2 and the transforming gene E6 are required for papilloma formation. Frameshift mutations were generated in the individual genes in the context of a full-length cottontail rabbit papillomavirus genome, and the mutant DNAs were intradermally inoculated into domestic rabbits. None of the mutants induced papillomas. Marker rescue experiments confirmed that the defects were due to mutations that we deliberately introduced. Marker rescue also confirmed our previous report that the upstream region of E7 around position 9 was critical for papilloma induction. These results demonstrate that the E1 and E2 regulatory genes as well as the E6 and E7 transforming genes are each required for papilloma formation. Each gene may provide molecular targets for therapeutic intervention.

Wu, X; Xiao, W; Brandsma, J L

1994-01-01

253

An E7-based therapeutic vaccine protects mice against HPV16 associated cancer.  

PubMed

Plant-derived vaccines represent an attractive strategy for cancer immunotherapy due to their relative safety and cost-effectiveness. We evaluated the anti-tumour activity of a Nicotiana benthamiana produced vaccine candidate based on the non-transforming E7 protein of HPV-16 fused to beta-1,3-1,4-glucanase of Clostridium thermocellum. Two doses of vaccine at two week intervals were administered to groups of C57BL/6 mice starting 3 or 6 days after challenge with tumourigenic E7-expressing TC-1* cells. Inhibition of tumour growth and increased survival was observed in both groups treated with vaccine. These data suggest the potential of plants as a platform for producing therapeutic vaccines. PMID:19200826

Venuti, Aldo; Massa, Silvia; Mett, Vadim; Vedova, Laura Dalla; Paolini, Francesca; Franconi, Rosella; Yusibov, Vidadi

2009-02-05

254

The Heterogeneous Structural Behavior of E7 from HPV16 Revealed by NMR Spectroscopy.  

PubMed

The E7 protein from human papillomavirus (HPV) plays a key role in oncogenesis; for this reason, it is a target of great biomedical interest. To date, no high resolution information is available for the full protein. We present here the NMR characterization of the entire E7 from HPV16, one of the most oncogenic variants of the virus. The protein is very heterogeneous in terms of structural and dynamic properties with a highly flexible N-terminal module and a more structured C terminus. This opens possibilities for studies of molecular-level interactions and post-translational modifications of the protein to unravel functional details that might be linked to its highly oncogenic potential. PMID:23940009

Calçada, Eduardo O; Felli, Isabella C; Hošek, Tomáš; Pierattelli, Roberta

2013-08-12

255

Defective K-Ras oncoproteins overcome impaired effector activation to initiate leukemia in vivo.  

PubMed

Reversing the aberrant biochemical output of oncogenic Ras proteins is one of the great challenges in cancer therapeutics; however, it is uncertain which Ras effectors are required for tumor initiation and maintenance. To address this question, we expressed oncogenic K-Ras(D12) proteins with "second site" amino acid substitutions that impair PI3 kinase/Akt or Raf/MEK/ERK activation in bone marrow cells and transplanted them into recipient mice. In spite of attenuated signaling properties, defective K-Ras oncoproteins initiated aggressive clonal T-lineage acute lymphoblastic leukemia (T-ALL). Murine T-ALLs expressing second site mutant proteins restored full oncogenic Ras activity through diverse mechanisms, which included acquiring novel somatic third site Kras(D12) mutations and silencing PTEN. T-ALL cell lines lacking PTEN had elevated levels of phosphorylated Akt, a gene expression pattern similar to human early T-cell precursor ALL, and were resistant to the potent and selective MEK inhibitor PD0325901. Our data, which demonstrate strong selective pressure to overcome the defective activation of PI3 kinase/Akt and Raf/MEK/ERK, implicate both Ras effector pathways as drivers of aberrant growth in T-ALL and further suggest that leukemia cells will deploy multiple mechanisms to develop resistance to targeted inhibitors in vivo. PMID:23637129

Shieh, Angell; Ward, Ashley F; Donlan, Kegan L; Harding-Theobald, Emily R; Xu, Jin; Mullighan, Charles G; Zhang, Chao; Chen, Shann-Ching; Su, Xiaoping; Downing, James R; Bollag, Gideon E; Shannon, Kevin M

2013-05-01

256

The oncoprotein BCL11A binds to orphan nuclear receptor TLX and potentiates its transrepressive function.  

PubMed

Nuclear orphan receptor TLX (NR2E1) functions primarily as a transcriptional repressor and its pivotal role in brain development, glioblastoma, mental retardation and retinopathologies make it an attractive drug target. TLX is expressed in the neural stem cells (NSCs) of the subventricular zone and the hippocampus subgranular zone, regions with persistent neurogenesis in the adult brain, and functions as an essential regulator of NSCs maintenance and self-renewal. Little is known about the TLX social network of interactors and only few TLX coregulators are described. To identify and characterize novel TLX-binders and possible coregulators, we performed yeast-two-hybrid (Y2H) screens of a human adult brain cDNA library using different TLX constructs as baits. Our screens identified multiple clones of Atrophin-1 (ATN1), a previously described TLX interactor. In addition, we identified an interaction with the oncoprotein and zinc finger transcription factor BCL11A (CTIP1/Evi9), a key player in the hematopoietic system and in major blood-related malignancies. This interaction was validated by expression and coimmunoprecipitation in human cells. BCL11A potentiated the transrepressive function of TLX in an in vitro reporter gene assay. Our work suggests that BCL11A is a novel TLX coregulator that might be involved in TLX-dependent gene regulation in the brain. PMID:22675500

Estruch, Sara B; Buzón, Víctor; Carbó, Laia R; Schorova, Lenka; Lüders, Jens; Estébanez-Perpiñá, Eva

2012-06-04

257

The TCL1A Oncoprotein Interacts Directly with the NF-?B Inhibitor I?B  

PubMed Central

The T cell leukaemia/lymphoma 1A (TCL1A) oncoprotein plays key roles in several B and T cell malignancies. Lacking enzymatic activity, TCL1A's transforming action was linked to its capacity to co-activate the protein kinase AKT via binding to its pleckstrin homology (PH) domain. However, perturbation of AKT signalling alone was recently shown insufficient to explain TCL1A oncogenesis, suggesting that TCL1A has additional cellular partners. Searching for such additional targets, we found that TCL1A binds specifically and directly to the ankyrin domain of I?B, the inhibitor of the NF-?B transcription factors. Through binding assays and a structural analysis by small angle X-ray scattering, we show that TCL1A and I?B interact in yeast-two-hybrid systems, when transiently overexpressed in 293 cells, and as recombinant proteins in vitro. We further establish that the association between TCL1A and I?B is compatible with AKT binding to TCL1A, but incompatible with I?B binding to NF-?B. By interfering with the inhibition of NF-?B by I?B, TCL1A may increase the concentration of free NF-?B molecules sufficiently to trigger expression of anti-apoptotic genes. Thus our data suggest an additional route by which TCL1A might cause cancer.

Ropars, Virginie; Despouy, Gilles; Stern, Marc-Henri; Benichou, Serge; Roumestand, Christian; Arold, Stefan T.

2009-01-01

258

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.

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

2013-01-01

259

HPV16 E7 protein and hTERT proteins defective for telomere maintenance cooperate to immortalize human keratinocytes.  

PubMed

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

2013-04-04

260

Genus specific features of bovine papillomavirus E6, E7, E5 and E8 proteins  

Microsoft Academic Search

Six bovine papillomavirus (BPV) types, BPV-1 to -6, have been classified in genera Delta-papillomavirus (BPV-1 and -2), Epsilon-papillomavirus (BPV-5) and Xi-papillomavirus (BPV-3, -4 and -6). In addition, 16 unclassified putative BPV types have been reported. In the present study, we characterized genus specific features of E6, E7, E5 (formerly E8) and E8 proteins of seven putative BPV types, BAPV-1, -2,

Yoshimi Tomita; Tomoko Ogawa; Zhongri Jin; Hiroshi Shirasawa

2007-01-01

261

Inhibition of HPV16 E6yE7 immortalization of normal keratinocytes by hairpin ribozymes  

Microsoft Academic Search

HPV-16 E6 and E7 genes are required to efficiently immortalize a broad spectrum of cell types includ- ing cervical keratinocytes. Therefore, the E6yE7 genes can be considered relevant targets for anti-cancer therapy. We pro- duced several engineered hairpin (HP) ribozymes to specifi- cally disrupt HPV-16 E6yE7 mRNA. After extensive biochem- ical characterization, one anti-E6 HP ribozyme (R434) was selected for

LUIS M. ALVAREZ-SALAS; AMY E. CULLINAN; A NDREW SIWKOWSKI; A RNOLD HAMPEL; JOSEPH A. DIPAOLO

262

Inhibition of topoisomerase IIalpha expression by transforming growth factor-beta1 is abrogated by the papillomavirus E7 protein.  

PubMed

Transforming growth factor-beta (TGF-beta) protects normal cells from etoposide-induced cell death, yet the mechanism has remained speculative. Studies have shown that etoposide modifies the activity of the topoisomerase IIalpha (topo IIalpha) enzyme, thereby causing DNA damage and inducing cell death. Expression of topo IIalpha is necessary for etoposide-induced cell death, and peak expression of topo IIalpha normally occurs during the G2 phase of the cell cycle. We predicted that by arresting growth in the G1 phase, TGF-beta1 would prevent the induction of topo IIalpha expression that normally occurs subsequent to the G1-S transition, thereby protecting cells from etoposide-induced cell death. Accordingly, we hypothesized that the inhibition of topo IIalpha expression by TGF-beta1 would be dependent on the ability of TGF-beta1 to arrest cell cycle progression in G1. Using mink lung epithelial cells (MvlLu), we found that TGF-beta1 decreases topo IIalpha mRNA expression, and the decrease occurs as cells begin to accumulate in the G1 phase of the cell cycle. Topo IIalpha protein expression decreases subsequent to the fall in mRNA expression. In contrast, topo IIalpha expression is not affected by TGF-beta1 in cells that fail to undergo G1 arrest because of inactivation of the retinoblastoma tumor suppressor protein (pRb) by the papillomavirus type 16 E7 protein. Our studies suggest that inhibition of topo IIalpha by TGF-beta1 is the principal mechanism that protects mink lung epithelial cells (Mv1Lu) from etoposide-induced toxicity. Furthermore, the inhibition of topo IIalpha protein expression by TGF-beta1 is dependent on pRb-mediated cell cycle arrest, suggesting that TGF-beta1 will not reduce the sensitivity of pRb-deficient cancers to etoposide. PMID:11156401

Satterwhite, D J; White, R L; Matsunami, N; Neufeld, K L

2000-12-15

263

Cloning, purification and metal binding of the HNH motif from colicin E7.  

PubMed

The HNH family of endonucleases is characterized by a ??? metal-finger structural motif. Colicin E7 is a representative member of this family containing the strictly conserved HNH motif at its C-terminus. Structural and biochemical studies suggested that the HNH motif could contain all the residues necessary for metal ion binding and nuclease activity. In this work a 43 amino acid peptide extending from V534 to K576 of colicin E7 and encompassing the HNH motif was cloned and expressed in Escherichia coli as a ubiquitin fusion protein. The N-terminal fusion tag was cleaved off by a specific protease, and the HNH peptide was purified free of ubiquitin. Circular dichroism, fluorescence and mass spectrometry showed that the zinc-ion binding affinity of the purified HNH peptide was much weaker than that of the intact nuclease domain suggesting that the N-terminal part of the nuclease domain is essential for stabilizing the structure of the HNH motif. The coordination sphere of the metal ion was found to be not fully equipped by the ligand - leaving a free coordination site for the substrate. Neither DNA binding nor DNAse activity of the purified HNH peptide was detected. Comparison of the glutathion-S-transferase-fused N-terminal deletion mutants of the colicin E7 nuclease domain suggested that the presence of the DNA-binding site is still not sufficient for the catalytic activity. PMID:23563167

Gyurcsik, Béla; Czene, Anikó; Jankovics, Hajnalka; Jakab-Simon, Noémi I; ?laska-Kiss, Krystyna; Kiss, Antal; Kele, Zoltán

2013-04-04

264

Structure and Catalytic Mechanism of the Thioesterase CalE7 in Enediyne Biosynthesis*  

PubMed Central

The biosynthesis of the enediyne moiety of the antitumor natural product calicheamicin involves an iterative polyketide synthase (CalE8) and other ancillary enzymes. In the proposed mechanism for the early stage of 10-membered enediyne biosynthesis, CalE8 produces a carbonyl-conjugated polyene with the assistance of a putative thioesterase (CalE7). We have determined the x-ray crystal structure of CalE7 and found that the subunit adopts a hotdog fold with an elongated and kinked substrate-binding channel embedded between two subunits. The 1.75-? crystal structure revealed that CalE7 does not contain a critical catalytic residue (Glu or Asp) conserved in other hotdog fold thioesterases. Based on biochemical and site-directed mutagenesis studies, we proposed a catalytic mechanism in which the conserved Arg37 plays a crucial role in the hydrolysis of the thioester bond, and that Tyr29 and a hydrogen-bonded water network assist the decarboxylation of the ?-ketocarboxylic acid intermediate. Moreover, computational docking suggested that the substrate-binding channel binds a polyene substrate that contains a single cis double bond at the C4/C5 position, raising the possibility that the C4=C5 double bond in the enediyne moiety could be generated by the iterative polyketide synthase. Together, the results revealed a hotdog fold thioesterase distinct from the common type I and type II thioesterases associated with polyketide biosynthesis and provided interesting insight into the enediyne biosynthetic mechanism.

Kotaka, Masayo; Kong, Rong; Qureshi, Insaf; Ho, Qin Shi; Sun, Huihua; Liew, Chong Wai; Goh, Lan Pei; Cheung, Peter; Mu, Yuguang; Lescar, Julien; Liang, Zhao-Xun

2009-01-01

265

Transforming growth factor beta1 induces differentiation in human papillomavirus-positive keratinocytes.  

PubMed Central

Human papillomaviruses (HPVs) are implicated in the etiology of anogenital cancers. Expression of the HPV E6 and E7 oncoproteins is believed to contribute to the carcinogenic process. Progressive loss of the ability to differentiate and resistance to the growth-inhibitory effects of endogenous signals also appear important in multistep tumorigenesis. Transforming growth factor beta1 (TGF-beta1) is a potent growth inhibitor for a variety of cultured cells. There have been conflicting reports on the ability of TGF-beta1 to inhibit the growth of HPV-positive keratinocytes in monolayer cultures. We have employed the organotypic (raft) tissue culture system, which more accurately mimics the in vivo cellular environment and architecture. We have investigated the TGF-beta1 response of HPV-positive keratinocytes derived from neoplastic cervical biopsies. Growth of these cell lines as raft tissues showed that many were altered in the ability to stratify and synthesize differentiation-specific proteins. When the organotypic tissues were treated with TGF-beta1, a more complete differentiation of the keratinocytes was induced. Treatment with 12-0-tetradecanoylphorbol-13-acetate gave similar results. TGF-beta1 treatment of HPV-positive raft epithelia led to a dose-dependent increase in E7 RNA expression in contrast to results from previous studies with monolayer cultures. Furthermore, TGF-beta1 interfered with the proliferation of HPV-positive cell lines grown in monolayer cultures. Our results suggest that loss of the ability to express markers of differentiation, a characteristic of malignancy, is a two-step process. The first step is reversible; the second is irreversible.

Ozbun, M A; Meyers, C

1996-01-01

266

A "public" T-helper epitope of the E7 transforming protein of human papillomavirus 16 provides cognate help for several E7 B-cell epitopes from cervical cancer-associated human papillomavirus genotypes.  

PubMed Central

We have identified a major T-cell epitope, amino acids 48-54 (DRAHYNI, in one-letter code) in the E7 open reading frame protein of human papillomavirus (HPV) type 16. Lymph node cells from mice immunized with synthetic peptides containing DRAHYNI proliferated and produced interleukin when challenged in vitro with peptide or whole HPV-16 E7 fusion protein. The T epitope was recognized in association with all five major histocompatibility complex class II I-A and I-E alleles tested. Synthetic peptides consisting of DRAHYNI linked to major B-cell epitopes on the E7 molecule formed immunogens capable of eliciting strong antibody responses to HPV-16 E7. The T epitope could provide help for the production of antibody to several B epitopes simultaneously, including a B epitope of HPV-18 E7 protein. Mice immunized with a peptide containing DRAHYNI and B epitope and, at a later date, infected with recombinant vaccinia E7 virus, displayed secondary antibody responses to E7. Because E7 has a role in cell transformation and is the most abundant viral protein in HPV-associated neoplastic cervical epithelial cells, the data have implications for vaccine strategies.

Tindle, R W; Fernando, G J; Sterling, J C; Frazer, I H

1991-01-01

267

Polymer\\/Liquid Crystal Composites: Phase Separation and Morphology of Blends of PBMA or PMMA and E7  

Microsoft Academic Search

Phase separation behaviour has been investigated for composite films made of the nematic mixture E7 embedded in a thermoplastic matrix of PBMA or PMMA Different approaches, based on optical and calorimetric analyses, have been applied to PDLC films, prepared by solvent coating techniques followed by thermal treatments, in order to determine the solubility limit of E7 in the matrices and

Luca Carpaneto; Annamaria Ristagno; Paola Stagnaro; Barbara Valenti

1996-01-01

268

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

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

1993-01-01

269

Binding and Internalization of Iron Oxide Nanoparticles Targeted to Nuclear Oncoprotein  

PubMed Central

A targeted nanoconjugate is being developed for non-invasive detection of gene expression in cells expressing the JC virus oncoprotein, T-antigen, which has been associated with medulloblastoma and other cancers. JC virus T-antigen localizes predominantly to the nucleus via a classical monopartite nuclear localization signal (NLS). An antibody fragment which recognizes JC virus T-antigen was attached to cross-linked dextran coated iron oxide nanoparticles. Radiolabeled conjugates were added to mouse medulloblastoma cells expressing the target T-antigen to test their ability to bind to tumor cells and be internalized by the cells. All conjugates containing targeting antibody bound to cells and were internalized, with increasing levels over time. There was no difference in cell binding or internalization among conjugates containing 2, 4, 6 or 8 antibody fragments per nanoparticle. Conjugates with only nonspecific antibody on nanoparticles, or unconjugated nonspecific antibody, had significantly lower total binding and internalization than conjugates with targeting antibody. Unconjugated targeting antibody had equivalent or lower cell uptake compared with targeted nanoparticle conjugates. Specificity of uptake was demonstrated by >80% reduction of nanoconjugate uptake in the presence of 100 fold excess of unconjugated antibody. The presence of a membrane translocation peptide (Tat) on the nanoparticles in addition to targeting antibody did not improve nanoconjugate internalization over the internalization caused by the antibody alone. This antibody nanoconjugate demonstrates feasibility of targeting a nuclear protein and suggests that a minimum number of antibody fragments per nanoparticle are sufficient for achieving binding specificity and efficient uptake into living cells.

Knight, Linda C.; Romano, Jan E.; Krynska, Barbara; Faro, Scott; Mohamed, Feroze B.; Gordon, Jennifer

2013-01-01

270

Highly potent and specific siRNAs against E6 or E7 genes of HPV16- or HPV18-infected cervical cancers.  

PubMed

Infection with high-risk types (type 16 or type 18) of human papillomaviruses (HPVs) increases a patient's risk of cervical cancer. Given the importance of the cervix and the severe side effects resulting from traditional cancer therapies, this study aimed to achieve targeted inhibition of viral oncogenes in tumor cells using small interfering RNAs (siRNA). To accomplish this, we developed nine siRNAs against either the E6 or E7 genes of HPV-16 or HPV-18 in several combinations, yielding siRNAs targeting 16E6, 16E7, 18E6 and 18E7. We measured the effectiveness of the siRNAs by examining E6 or E7 mRNA expression after transfection of the siRNAs into HPV-positive CaSki (HPV-16) or HeLa (HPV-18) cell lines. We found that the HPV-siRNAs significantly reduced cell growth and colony formation in both cell lines. Flow cytometry analysis revealed a significant increase in apoptosis. The siRNAs had no effect on cell growth, colony formation or apoptosis in HPV-negative C33A cells, demonstrating a lack of off-target effects. In addition, an in vivo xenograft study showed that intra-tumoral injection of the siRNAs reduced tumor growth in BALB/c nude mice. In conclusion, we have developed highly specific and potent HPV-siRNAs that successfully suppress tumor growth and induce apoptosis in HPV-positive cervical cancer cells. siRNA treatment has potential for further development as an adjuvant therapy for cervical cancer. PMID:20885450

Chang, J T-C; Kuo, T-F; Chen, Y-J; Chiu, C-C; Lu, Y-C; Li, H-F; Shen, C-R; Cheng, A-J

2010-10-01

271

Vaccination with HPV16 L2E6E7 fusion protein in GPI-0100 adjuvant elicits protective humoral and cell-mediated immunity  

PubMed Central

A vaccine comprising human papillomavirus type 16 (HPV16) L2, E6 and E7 in a single tandem fusion protein (termed TA-CIN) has the potential advantages of both broad cross-protection against HPV transmission through induction of L2 antibodies able to cross neutralize different HPV types and of therapy by stimulating T cell responses targeting HPV16 early proteins. However, patients vaccinated with TA-CIN alone develop weak HPV neutralizing antibody and E6/E7-specific T cell responses. Here we test TA-CIN formulated along with the adjuvant GPI-0100, a semi-synthetic quillaja saponin analog that was developed to promote both humoral and cellular immune responses. Subcutaneous administration to mice of TA-CIN (20 ?g) with 50 ?g GPI-0100, three times at biweekly intervals, elicited high titer HPV16 neutralizing serum antibody, robust neutralizing titers for other HPV16-related types, including HPV31 and HPV58, and neutralized to a lesser extent other genital mucosatropic papillomaviruses like HPV18, HPV45, HPV6 and HPV11. Notably, vaccination with TA-CIN in GPI-0100 protected mice from cutaneous HPV16 challenge as effectively as HPV16 L1 VLP without adjuvant. Formulation of TA-CIN with GPI-0100 enhanced the production of E7-specific, interferon ? producing CD8+ T cell precursors by 20-fold. Vaccination with TA-CIN in GPI-0100 also completely prevented tumor growth after challenge with 5 × 104 HPV16-transformed TC-1 tumor cells, whereas vaccination with TA-CIN alone delayed tumor growth. Furthermore, three monthly vaccinations with 125 ?g of TA-CIN and 1000 ?g GPI-0100 were well tolerated by pigtail macaques and induced both HPV16 E6/E7-specific T cell responses and serum antibodies that neutralized all HPV types tested.

Karanam, Balasubramanyam; Gambhira, Ratish; Peng, Shiwen; Jagu, Subhashini; Kim, Dae-Jin; Ketner, Gary W.; Stern, Peter L.; Adams, Robert J.; Roden, Richard B.S.

2010-01-01

272

The HECT-domain ubiquitin ligase Huwe1 controls neural differentiation and proliferation by destabilizing the N-Myc oncoprotein.  

PubMed

Development of the nervous system requires that timely withdrawal from the cell cycle be coupled with initiation of differentiation. Ubiquitin-mediated degradation of the N-Myc oncoprotein in neural stem/progenitor cells is thought to trigger the arrest of proliferation and begin differentiation. Here we report that the HECT-domain ubiquitin ligase Huwe1 ubiquitinates the N-Myc oncoprotein through Lys 48-mediated linkages and targets it for destruction by the proteasome. This process is physiologically implemented by embryonic stem (ES) cells differentiating along the neuronal lineage and in the mouse brain during development. Genetic and RNA interference-mediated inactivation of the Huwe1 gene impedes N-Myc degradation, prevents exit from the cell cycle by opposing the expression of Cdk inhibitors and blocks differentiation through persistent inhibition of early and late markers of neuronal differentiation. Silencing of N-myc in cells lacking Huwe1 restores neural differentiation of ES cells and rescues cell-cycle exit and differentiation of the mouse cortex, demonstrating that Huwe1 restrains proliferation and enables neuronal differentiation by mediating the degradation of N-Myc. These findings indicate that Huwe1 links destruction of N-Myc to the quiescent state that complements differentiation in the neural tissue. PMID:18488021

Zhao, Xudong; Heng, Julian Ik-Tsen; Guardavaccaro, Daniele; Jiang, Richeng; Pagano, Michele; Guillemot, Francois; Iavarone, Antonio; Lasorella, Anna

2008-05-18

273

The HECT-domain ubiquitin ligase Huwe1 controls neural differentiation and proliferation by destabilizing the N-Myc oncoprotein  

PubMed Central

Development of the nervous system requires that timely withdrawal from the cell cycle be coupled with initiation of differentiation. Ubiquitin-mediated degradation of the N-Myc oncoprotein in neural stem/progenitor cells is thought to trigger the arrest of proliferation and begin differentiation. Here we report that the HECT-domain ubiquitin ligase Huwe1 ubiquitinates the N-Myc oncoprotein through Lys 48-mediated linkages and targets it for destruction by the proteasome. This process is physiologically implemented by embryonic stem (ES) cells differentiating along the neuronal lineage and in the mouse brain during development. Genetic and RNA interference-mediated inactivation of the Huwe1 gene impedes N-Myc degradation, prevents exit from the cell cycle by opposing the expression of Cdk inhibitors and blocks differentiation through persistent inhibition of early and late markers of neuronal differentiation. Silencing of N-myc in cells lacking Huwe1 restores neural differentiation of ES cells and rescues cell-cycle exit and differentiation of the mouse cortex, demonstrating that Huwe1 restrains proliferation and enables neuronal differentiation by mediating the degradation of N-Myc. These findings indicate that Huwe1 links destruction of N-Myc to the quiescent state that complements differentiation in the neural tissue.

Zhao, Xudong; Heng, Julian Ik-Tsen; Guardavaccaro, Daniele; Jiang, Richeng; Pagano, Michele; Guillemot, Francois; Iavarone, Antonio; Lasorella, Anna

2009-01-01

274

Cooperative Interaction between the MUC1-C Oncoprotein and the Rab31 GTPase in Estrogen Receptor-Positive Breast Cancer Cells  

PubMed Central

Rab31 is a member of the Ras superfamily of small GTPases that has been linked to poor outcomes in patients with breast cancer. The MUC1-C oncoprotein is aberrantly overexpressed in most human breast cancers and also confers a poor prognosis. The present results demonstrate that MUC1-C induces Rab31 expression in estrogen receptor positive (ER+) breast cancer cells. We show that MUC1-C forms a complex with estrogen receptor ? (ER?) on the Rab31 promoter and activates Rab31 gene transcription in an estrogen-dependent manner. In turn, Rab31 contributes to the upregulation of MUC1-C abundance in breast cancer cells by attenuating degradation of MUC1-C in lysosomes. Expression of an inactive Rab31(S20N) mutant in nonmalignant breast epithelial cells confirmed that Rab31 regulates MUC1-C expression. The functional significance of the MUC1-C/Rab31 interaction is supported by the demonstration that Rab31 confers the formation of mammospheres by a MUC1-C-dependent mechanism. Analysis of microarray databases further showed that (i) Rab31 is expressed at higher levels in breast cancers as compared to that in normal breast tissues, (ii) MUC1+ and ER+ breast cancers have increased levels of Rab31 expression, and (iii) patients with Rab31-positive breast tumors have a significantly decreased ten-year overall survival as compared to those with Rab31-negative tumors. These findings indicate that MUC1-C and Rab31 function in an autoinductive loop that contributes to overexpression of MUC1-C in breast cancer cells.

Jin, Caining; Rajabi, Hasan; Pitroda, Sean; Li, Ailing; Kharbanda, Akriti; Weichselbaum, Ralph; Kufe, Donald

2012-01-01

275

RNA interference against HPV16 E7 oncogene leads to viral E6 and E7 suppression in cervical cancer cells and apoptosis via upregulation of Rb and p53  

Microsoft Academic Search

The simultaneous expression of human papillomavirus type 16 (HPV16) E6 and E7 oncogenes is pivotal for malignant transformation\\u000a and maintenance of malignant phenotypes. Silencing these oncogenes is considered to be applicable in molecular therapies of\\u000a human cervical cancer. However, it remains to be determined whether HPV16 E6 and E7 could be both silenced to obtain most\\u000a efficient antitumor activity by

Ni Sima; Wei Wang; Debo Kong; Dongrui Deng; Qian Xu; Jianfeng Zhou; Gang Xu; Li Meng; Yunping Lu; Shixuan Wang; Ding Ma

2008-01-01

276

The S100A4 Oncoprotein Promotes Prostate Tumorigenesis in a Transgenic Mouse Model  

PubMed Central

S100A4, a calcium-binding protein, is known for its role in the metastatic spread of tumor cells, a late event of cancer disease. This is the first report showing that S100A4 is not merely a metastatic protein but also an oncoprotein that plays a critical role in the development of tumors. We earlier showed that S100A4 expression progressively increases in prostatic tissues with the advancement of prostate cancer (CaP) in TRAMP, an autochthonous mouse model. To study the functional significance of S100A4 in CaP, we generated a heterozygously deleted S100A4 (TRAMP/S100A4+/?) genotype by crossing TRAMP with S100A4?/? mice. TRAMP/S100A4+/? did not show a lethal phenotype, and transgenes were functional. As compared to age-matched TRAMP littermates, TRAMP/S100A4+/? mice exhibited 1) an increased tumor latency period (P < 0.001), 2) a 0% incidence of metastasis, and 3) reduced prostatic weights (P < 0.001). We generated S100A4-positive clones from S100A4-negative CaP cells and tested their potential. S100A4-positive tumors grew at a faster rate than S100A4-negative tumors in vitro and in a xenograft mouse model. The S100A4 protein exhibited growth factor–like properties in multimode (intracellular and extracellular) forms. We observed that 1) the growth-promoting effect of S100A4 is due to its activation of NF?B, 2) S100A4-deficient tumors exhibit reduced NF?B activity, 3) S100A4 regulates NF?B through the RAGE receptor, and 4) S100A4 and RAGE co-localize in prostatic tissues of mice. Keeping in view its growth-promoting role, we suggest that S100A4 qualifies as an excellent candidate to be exploited for therapeutic agents to treat CaP in humans.

Siddique, Hifzur R.; Adhami, Vaqar M.; Parray, Aijaz; Johnson, Jeremy J.; Siddiqui, Imtiaz A.; Shekhani, Mohammad T.; Murtaza, Imtiyaz; Ambartsumian, Noona; Konety, Badrinath R.; Mukhtar, Hasan

2013-01-01

277

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...

278

Correlation of cell cycle regulatory proteins (p53 and p16(ink)?(a)) and bcl-2 oncoprotein with mitotic index and thickness of primary cutaneous malignant melanoma.  

PubMed

The purpose of the study was to determine the frequency of expression p53 and p16INK4a proteins and bcl-2 oncoprotein in malignant skin melanoma and to determine their correlation with the proliferative index and tumor thickness. The study involved 53 patients: 27 (51%) male and 26 (49%) female. Mitotic index showed a correlation with p53 protein expression, a negative correlation with p16INK4a protein expression. Statistically significant correlations were determined between the Breslow tumor thickness, Clark invasion level and p53 protein expression, as well as Breslow tumor thickness and bcl-2 oncoprotein expression (p<0.05), whereas there was no correlation between the p16INK4a protein expression and melanoma thicknes and Clark invasion level. Overexpression p53 protein and bcl-2 oncoprotein, with the loss p16INK4a protein of expression in the nodular melanoma, confirms a frequent loss of function of these tumor suppressor gene and oncogene, and indicates a vertical tumor growth phase. The loss of tumor suppression function the p53 protein and bcl-2 oncoprotein overexpression in cutaneous melanoma correlates with larger tumor thickness, whereas the overexpression of mutated p53 protein and loss p16INK4a protein of expression indicate a higher proliferative tumour potential. Therefore, these evaluated proteins may be the aggressive biological tumour activity markers. PMID:21108607

Kostov, Miloš; Mijovi?, Zaklina; Mihailovi?, Dragan; Cerovi?, Snežana; Stojanovi?, Miroslav; Jeli?, Marija

2010-11-01

279

Different contribution of bovine papillomavirus type 1 oncoproteins to the transformation of equine fibroblasts.  

PubMed

Equine sarcoids represent the most common skin tumours in equids worldwide, characterized by localized invasion, rare regression and high recurrence following surgical intervention. Bovine papillomavirus type 1 (BPV-1) and less commonly BPV-2 are now widely recognized as the causative agents of the disease. Fibroblasts isolated from sarcoids are highly invasive. Invasion is associated with a high level of viral gene expression and matrix metalloproteinase upregulation. However, it remains unclear to what extent BPV-1 proteins are involved in the transformation of equine cells. To address this question, the individual viral genes E5, E6 and E7 were overexpressed in normal equine fibroblasts (EqPalF cells) and in the immortal but not fully transformed sarcoid-derived EqS02a cell line. The proliferation and invasiveness of these cell lines were assessed. E5 and E6 were found to be responsible for the enhanced cell proliferation and induction of increased invasion in EqS02a cells, whilst E7 appeared to enhance cell anchorage independence. Knockdown of BPV-1 oncogene expression by small interfering RNA reversed the transformed phenotype of sarcoid fibroblasts. Together, these observations strongly suggest that BPV-1 proteins play indispensable roles in the transformation of equine fibroblasts. These data also suggest that BPV-1 proteins are potential drug targets for equine sarcoid therapy. PMID:21177927

Yuan, ZhengQiang; Gault, Elizabeth A; Campo, M Saveria; Nasir, Lubna

2010-12-22

280

Apolipoprotein E5 and E7 in apparently healthy Japanese males: Frequencies and relation to plasma lipid levels  

Microsoft Academic Search

Summary In order to determine the frequencies of apolipoproteins (apo) E5 and E7 and their relation to plasma lipid levels, apo E phenotypes were determined in 608 healthy Japanese male adults by two-dimensional gel electrophoresis. Apo E5 and E7 were observed in 2.8% of the subjects, in addition to the three common apo E isoforms, E2, E3, and E4. Apo

Yasuko Yamanouchi; Tadao Arinami; Shigeru Tsuchiya; Ryunosuke Miyazaki; Haruyoshi Takaki; Takako Takano; Hideo Hamaguchi

1994-01-01

281

Identification of RNA aptamers that internalize into HPV-16 E6/E7 transformed tonsillar epithelial cells.  

PubMed

Human papillomavirus type 16 (HPV-16) associated oropharyngeal cancers are on a significant increase and better therapeutic strategies are needed. The HPV-16 oncogenes E6 and E7 are expressed in HPV-associated cancers and are able to transform human tonsillar epithelial cells (HTECs). We used cell-Systematic Evolution of Ligands by Exponential Enrichment (SELEX) to select for RNA aptamers that entered into HPV-16 E6/E7-HTECs. After 12 rounds of cell-SELEX, a pool of aptamers was obtained that had significantly greater internalization capacity (~5-fold) into E6/E7-HTECs as compared to primary HTECs or fibroblasts. Analysis of individual aptamers from the pool indicated variable internalization into E6/E7-HTECs (1-8-fold as compared to a negative control). Most of the individual aptamers internalized into E6/E7 and primary HTECs with similar efficiency, while one aptamer exhibited ~3-fold better internalization into E6/E7-HTECs. Aptamers that internalize into cells may be useful for delivering therapeutic agents to HPV-16 associated malignancies. PMID:24074596

Gourronc, Francoise A; Rockey, William M; Thiel, William H; Giangrande, Paloma H; Klingelhutz, Aloysius J

2013-09-08

282

Detection of Immunoglobulin G against E7 of Human Papillomavirus in Non-Small-Cell Lung Cancer  

PubMed Central

Background. A significant number of non-small-cell lung cancers (NSCLC) have human papillomavirus (HPV) DNA integrated in their genome. This study sought to further establish HPV's possible etiologic link to NSCLC by evaluating an immune response to HPV's oncogene, E7, in patients with NSCLC. Patients and Methods. Antibodies (IgG) in serum against E7 for HPV 16 and 18 in 100 patients with NSCLC were examined by enzyme-linked immunosorbent assay (ELISA). Results. Sixteen NSCLC patients were found to have a high titration of IgG for HPV oncogenic E7 protein. 23.5% of adenocarcinomas (AC,) and 15.4% of squamous cell carcinomas (SCC) were positive for IgG against HPV E7. HPV-18 (11%) had a slightly higher frequency than HPV-16 (6%). Of the six positive cases for HPV-16, 3 were AC, 2 SCC, and 1 NOS (not otherwise specified). For the 11 HPV-18 positives, 7 were AC, and 4 SCC. The one case with IgG against HPV 16 and 18 was AC. One case had high cross-reactive levels against E7 of HPV 16 and 18. Two (28%) of 7 patients who reported never smoking were positive for HPV, and 12 (13.6%) of 88 smokers were HPV positive. Conclusions. The study detected high levels of IgG against E7 in 16% of NSCLC patients. This adds evidence to a potential role of HPV in the pathogenesis of NSCLC.

Joh, Joongho; Kwon, Amy; Jenson, A. Bennett; Ghim, Shin-je; Kloecker, Goetz H.

2013-01-01

283

HPV16 synthetic long peptide (HPV16-SLP) vaccination therapy of patients with advanced or recurrent HPV16-induced gynecological carcinoma, a phase II trial  

PubMed Central

Background Human papilloma virus type 16 (HPV16)-induced gynecological cancers, in particular cervical cancers, are found in many women worldwide. The HPV16 encoded oncoproteins E6 and E7 are tumor-specific targets for the adaptive immune system permitting the development of an HPV16-synthetic long peptide (SLP) vaccine with an excellent treatment profile in animal models. Here, we determined the toxicity, safety, immunogenicity and efficacy of the HPV16 SLP vaccine in patients with advanced or recurrent HPV16-induced gynecological carcinoma. Methods Patients with HPV16-positive advanced or recurrent gynecological carcinoma (n?=?20) were subcutaneously vaccinated with an HPV16-SLP vaccine consisting of a mix of 13 HPV16 E6 and HPV16 E7 overlapping long peptides in Montanide ISA-51 adjuvant. The primary endpoints were safety, toxicity and tumor regression as determined by RECIST. In addition, the vaccine-induced T-cell response was assessed by proliferation and associated cytokine production as well as IFN?-ELISPOT. Results No systemic toxicity beyond CTCAE grade II was observed. In a few patients transient flu-like symptoms were observed. In 9 out of 16 tested patients vaccine-induced HPV16-specific proliferative responses were detected which were associated with the production of IFN?, TNF?, IL-5 and/or IL-10. ELISPOT analysis revealed a vaccine-induced immune response in 11 of the 13 tested patients. The capacity to respond to the vaccine was positively correlated to the patient’s immune status as reflected by their response to common recall antigens at the start of the trial. Median survival was 12.6 ± 9.1?months. No regression of tumors was observed among the 12 evaluable patients. Nineteen patients died of progressive disease. Conclusions The HPV16-SLP vaccine was well tolerated and induced a broad IFN?-associated T-cell response in patients with advanced or recurrent HPV16-induced gynecological carcinoma but neither induced tumor regression nor prevented progressive disease. We, therefore, plan to use this vaccine in combination with chemotherapy and immunomodulation.

2013-01-01

284

Human cytomegalovirus mtrII oncoprotein binds to p53 and down-regulates p53-activated transcription.  

PubMed Central

The 79-amino-acid (79-aa) open reading frame (UL111a) gene within morphological transforming region II (mtrII) of human cytomegalovirus strain Towne has been shown to transform rodent cells in vitro (J. Thompson, J. Doniger, and L. J. Rosenthal, Arch. Virol. 136:161-172, 1994). Moreover, a translation termination linker (TTL) mutant of mtrII that coded for the first 49 aa of mtrII oncoprotein (designated TTL49) was sufficient for malignant transformation, whereas a TTL mutant that coded for the first 24 aa (designated TTL24) was not. The current study demonstrates the binding of mtrII oncoprotein to the tumor suppressor protein p53 both in vivo using transiently transfected cells and in vitro using labeled proteins. Furthermore, the C-terminally truncated mtrII protein TTL49, but not truncated protein TTL24, bound to p53. The mtrII binding domain mapped to the N-terminal region of p53, residues 1 to 106, with a critical region from aa 27 to 44, whereas the p53 binding domain of mtrII protein was the first 49 aa. Furthermore, mtrII inhibited p53-activated transcription, indicating its ability to alter p53-directed cellular regulatory mechanisms. mtrII oncoprotein was detected both in stably transfected NIH 3T3 cell lines and human cytomegalovirus-infected HEL 299 cells (as early as 12 h after infection) in the perinuclear region and in the nucleus. mtrII-transformed cell lines, at both early and late passage, exhibited high levels of p53 with a 15-fold-extended half-life. However, p53-activated transcription was suppressed in these cells in spite of the increased p53 levels. Finally, the results with wild-type mtrII and its TTL mutants with respect to p53 binding, p53-activated transcription, and transforming ability suggest that the mechanism of mtrII transformation is linked to both p53 binding and disruption of p53 cell regulation.

Muralidhar, S; Doniger, J; Mendelson, E; Araujo, J C; Kashanchi, F; Azumi, N; Brady, J N; Rosenthal, L J

1996-01-01

285

Enhanced anti-tumor effect of a gene gun-delivered DNA vaccine encoding the human papillomavirus type 16 oncoproteins genetically fused to the herpes simplex virus glycoprotein D.  

PubMed

Anti-cancer DNA vaccines have attracted growing interest as a simple and non-invasive method for both the treatment and prevention of tumors induced by human papillomaviruses. Nonetheless, the low immunogenicity of parenterally administered vaccines, particularly regarding the activation of cytotoxic CD8+ T cell responses, suggests that further improvements in both vaccine composition and administration routes are still required. In the present study, we report the immune responses and anti-tumor effects of a DNA vaccine (pgD-E7E6E5) expressing three proteins (E7, E6, and E5) of the human papillomavirus type 16 genetically fused to the glycoprotein D of the human herpes simplex virus type 1, which was administered to mice by the intradermal (id) route using a gene gun. A single id dose of pgD-E7E6E5 (2 µg/dose) induced a strong activation of E7-specific interferon-? (INF-?)-producing CD8+ T cells and full prophylactic anti-tumor effects in the vaccinated mice. Three vaccine doses inhibited tumor growth in 70% of the mice with established tumors. In addition, a single vaccine dose consisting of the co-administration of pgD-E7E6E5 and the vector encoding interleukin-12 or granulocyte-macrophage colony-stimulating factor further enhanced the therapeutic anti-tumor effects and conferred protection to 60 and 50% of the vaccinated mice, respectively. In conclusion, id administration of pgD-E7E6E5 significantly enhanced the immunogenicity and anti-tumor effects of the DNA vaccine, representing a promising administration route for future clinical trials. PMID:21445524

Diniz, M O; Ferreira, L C S

2011-04-01

286

Nucleotide 880 splice donor site required for efficient transformation and RNA accumulation by human papillomavirus type 16 E7 gene.  

PubMed Central

Mutations within coding sequences of the various human papillomavirus type 16 (HPV-16) genes have been used to demonstrate that the HPV-16 E7 gene is necessary and sufficient for transformation of rodent cells. We now provide evidence that, in addition to E7 coding sequences, a small cis-acting region immediately flanking the 3' end of E7 coding sequences is also required for transformation. This was shown by translation termination linker insertion, progressive deletion analysis, and site-directed mutagenesis. Disruption of the nucleotide (nt) 880 splice donor site within the 3'-flanking region by deletion of as few as 4 nt or substitution of 3 nt totally abolished transformation. Regeneration of the wild-type sequence in a previously transformation-incompetent splice site mutant restored transformation. Mutating the wild-type splice donor site to the consensus splice site resulted in a stronger transformation phenotype, while mutating the +2 position of the consensus sequence significantly reduced the frequency of transformation. It was shown with RNase protection assays that the amount of E7 mRNA in transformation-deficient splice site mutants was much lower. Nuclear runoff experiments revealed that there was no change in the rate of synthesis of E7 message in the nt 880 splice site mutant. Furthermore, mutations of HPV-16 sequences indicated that the two other early region splice donor sites have no more than minor roles in transformation and efficient RNA accumulation. These results indicate that the specific integrity of the nt 880 splice donor site is essential for both accumulation of E7 RNA and efficient E7-mediated transformation. Images

Belaguli, N S; Pater, M M; Pater, A

1992-01-01

287

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

PubMed

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. PMID:21821000

Lee, Kiwon; Lee, Ah-Young; Kwon, Yunhee Kim; Kwon, Hyockman

2011-07-29

288

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

2012-11-29

289

Novel oligomannose liposome-DNA complex DNA vaccination efficiently evokes anti-HPV E6 and E7 CTL responses.  

PubMed

The aim of this study was to establish an efficient human papilloma virus (HPV) type 16-targeting cancer immunotherapy. Persistent high-risk HPV infection causes cervical intra-epithelial neoplasia (CIN) and subsequent cervical carcinoma. HPV type16 (HPV16) is one of the common carcinogenic types and is found in about 50% of invasive cervical carcinomas. HPV16-derived viral proteins E6 and E7 are expressed in cancerous cells through the progression of the disease and have a role in carcinogenesis but are not expressed in normal cells. Thus, these proteins are regarded as ideal antigens for cervical carcinoma immunotherapy. In this study, we generated a novel HPV 16 E6 and E7 gene plasmid containing oligomannose liposomes (OML-HPV). We compared the cytotoxic T lymphocyte (CTL) induction efficiency of OML-HPV and that of standard liposome-HPV16 E6 and E7 DNA complex. HPV16 E6-specific CTLs could be generated from HPV 16-positive cervical carcinoma patient's peripheral blood mononuclear cells (PBMCs) by stimulating OML-HPV, but could not by stimulating standard liposome-HPV 16 E6, E7 DNA complex. Furthermore, we screened HLA-A24-restricted HPV16 E6- and E7-derived peptides, and found that one E6-derived peptide (E6 66-74) showed the highest immunogenicity with ELISPOT assay from 100% of HPV16-positive patients (4 out of 4). On the other hand, other E6- or E7-derived peptides, including E6 49-57, E6 82-90, E6 87-95, E6 98-106 and E7 83-93, showed less frequent reactivity. These results indicate that OML-HPV is a more effective approach than DNA vaccination using standard liposomes, and that a novel HLA-A24-restricted peptide, E6 66-74, might be a suitable target of cervical cancer immunotherapy. PMID:22032938

Mizuuchi, Masahito; Hirohashi, Yoshihiko; Torigoe, Toshihiko; Kuroda, Takafumi; Yasuda, Kazuyo; Shimizu, Yoshitaka; Saito, Tsuyoshi; Sato, Noriyuki

2011-10-15

290

Rational design of DNA vaccines for the induction of human papillomavirus type 16 E6- and E7-specific cytotoxic T-cell responses.  

PubMed

Many DNA vaccine candidates have been developed for the treatment of human papillomavirus type 16 (HPV16)-induced malignancies. Most of these vaccines consist of a fusion of E7 with a "carrier-protein" that functions to increase the potency of the vaccine. The nature of these carrier-proteins varies widely, and the mechanisms proposed to explain the enhanced immunogenicity of such fusions are often linked to the biological function of the carrier-protein. However, the potentiating effect of these carrier-proteins might also be explained by more general mechanisms, such as the provision of CD4+ T-cell help, increased antigen stability, or altered subcellular localization of the antigen. To assess whether these more generic mechanisms could suffice to generate highly immunogenic DNA vaccines, we evaluated a series of modular HPV16 E7 DNA vaccines in which the presence of CD4+ T-cell help, the presence of an endogenous carrier-protein, and the subcellular localization of the antigen could be systematically altered. Using this approach, we demonstrate that the addition of an element that provides CD4+ T-cell help, elements that enforce endoplasmic reticulum (ER) localization/retention are both necessary and sufficient to create markedly effective HPV16 E7-directed DNA vaccines. Importantly, the resulting design rules also apply to an HPV16 E6-directed DNA vaccine. The developed "HELP(ER)" HPV DNA vaccines encode only very limited additional sequences besides the antigen, thereby reducing the risk of antigenic competition and/or autoimmunity. PMID:22971245

Oosterhuis, Koen; Aleyd, Esil; Vrijland, Kim; Schumacher, Ton N; Haanen, John B

2012-10-31

291

MyD88 signal is required for more efficient induction of Ag-specific adaptive immune responses and antitumor resistance in a human papillomavirus E7 DNA vaccine model.  

PubMed

The function of MyD88 signals for induction of adaptive immunity is still controversial. Here we investigate using a human papillomavirus (HPV) 16 E7 DNA vaccine on MyD88 knock out mouse model whether MyD88 signals are required for induction of Ag-specific antibody and cellular responses, as well as antitumor resistance. When injected intramuscularly with E7 DNA vaccines, MyD88 deficient mice displayed antitumor protective responses to tumor cell challenges while having far lower responses than wild type mice. A similar finding was observed in antitumor therapeutic models by intramuscular-electroporation of E7 DNA vaccines. E7 DNA vaccines induced Ag-specific humoral and CD8+ CTL responses in MyD88 deficient mice. However, the levels were much less than those of wild type mice. These data suggest that the immune stimulatory sequence of E7 DNA vaccines and its signaling through MyD88 are not absolutely essential for induction of adaptive immune responses. However, MyD88 deficient mice co-delivered with MyD88 cDNA plus E7 DNA vaccines showed a recovery of Ag-specific IgG and CTL responses, and antitumor immunity to the levels of wild type mice, highlighting the importance of MyD88 signals for augmenting an adaptive immune response. Thus, these data clearly show that MyD88 signals are required only for more efficient induction of Ag-specific humoral and antitumor CD8+ CTL responses in this model. PMID:21496466

Sin, Jeong-Im

2011-04-13

292

Crosstalk Between BCR/ABL Oncoprotein and CXCR4 Signaling through a Src Family Kinase in Human Leukemia Cells  

PubMed Central

Stromal-derived factor (SDF)-1 and its G protein–coupled receptor, CXCR4, regulate stem/progenitor cell migration and retention in the marrow and are required for hematopoiesis. We show here an interaction between CXCR4 and the Src-related kinase, Lyn, in normal progenitors. We demonstrate that CXCR4-dependent stimulation of Lyn is associated with the activation of phosphatidylinositol 3-kinase (PI3-kinase). This chemokine signaling, which involves a Src-related kinase and PI3-kinase, appears to be a target for BCR/ABL, a fusion oncoprotein expressed only in leukemia cells. We show that the binding of phosphorylated BCR/ABL to Lyn results in the constitutive activation of Lyn and PI3-kinase, along with a total loss of responsiveness of these kinases to SDF-1 stimulation. Inhibition of BCR/ABL tyrosine kinase with STI571 restores Lyn responsiveness to SDF-1 signaling. Thus, BCR/ABL perturbs Lyn function through a tyrosine kinase-dependent mechanism. Accordingly, the blockade of Lyn tyrosine kinase inhibits both BCR/ABL-dependent and CXCR4-dependent cell movements. Our results demonstrate, for the first time, that Lyn-mediated pathological crosstalk exists between BCR/ABL and the CXCR4 pathway in leukemia cells, which disrupts chemokine signaling and chemotaxis, and increases the ability of immature cells to escape from the marrow. These results define a Src tyrosine kinases-dependent mechanism whereby BCR/ABL (and potentially other oncoproteins) dysregulates G protein–coupled receptor signaling and function of mammalian precursors.

Ptasznik, Andrzej; Urbanowska, Elzbieta; Chinta, Suneetha; Costa, Melinda A.; Katz, Benjamin A.; Stanislaus, Marisha A.; Demir, Gokhan; Linnekin, Diana; Pan, Zhixing K.; Gewirtz, Alan M.

2002-01-01

293

Sensitive detection of EML4-ALK fusion oncoprotein of lung cancer by in situ proximity ligation assay.  

PubMed

Abstract Background: EML4-ALK fusion oncogene has emerged as a novel molecular target in non-small cell lung cancer (NSCLC). Although break-apart fluorescent in situ hybridization (FISH) is the standard method for diagnosis, it is expensive, not readily available and sometimes difficult to interpret. In addition, ALK immunohistochemistry (IHC) may miss the diagnosis because of relatively low level of ALK transcription. Methods: In situ proximity ligation assay (PLA) originally developed for precise detection and quantification of proteins by dual recognition and amplification process was used for sensitive detection of EML4-ALK fusion oncoprotein in NSCLC cell lines (ALK negative cell: PC-9 and H460, ALK positive cell: H3122 and H2228). EML4-ALK oncogene and protein in lung cancer cells were confirmed by multiplex RT-PCR and Western blots. Results: We detected 117 kDa variant 1 of EML4-ALK in H3122 and 90 kDa variant 3 of EML4-ALK in H2228. These cells were more sensitive to crizotinib, an ALK inhibitor compared with PC-9 and H460 cells without EML4-ALK rearrangement. After fixing on glass slides by cytospin centrifuge, in situ PLA test was performed. Among four cell lines, distinct, tiny spots were visible only in H3122 and H2228 cell lines with ALK rearrangement. The same results were also obtained when paraffin-embedded cell blocks were used. Conclusions: Highly specific and sensitive detection of EML4-ALK fusion oncoprotein is possible by in situ PLA method suggesting its clinical application. PMID:23612660

Rho, Jin Kyung; Lee, Hyangsin; Park, Chan-Sik; Choi, Chang-Min; Lee, Jae Cheol

2013-09-01

294

The crystal structure of the immunity protein of colicin E7 suggests a possible colicin-interacting surface.  

PubMed Central

The immunity protein of colicin E7 (ImmE7) can bind specifically to the DNase-type colicin E7 and inhibit its bactericidal activity. Here we report the 1.8-angstrom crystal structure of the ImmE7 protein. This is the first x-ray structure determined in the superfamily of colicin immunity proteins. The ImmE7 protein consists of four antiparallel alpha-helices, folded in a topology similar to the architecture of a four-helix bundle structure. A region rich in acidic residues is identified. This negatively charged area has the greatest variability within the family of DNase-type immunity proteins; thus, it seems likely that this area is involved in specific binding to colicin. Based on structural, genetic, and kinetic data, we suggest that all the DNase-type immunity proteins, as well as colicins, share a "homologous-structural framework" and that specific interaction between a colicin and its cognate immunity protein relies upon how well these two proteins' charged residues match on the interaction surface, thus leading to specific immunity of the colicin. Images Fig. 1 Fig. 2 Fig. 5

Chak, K F; Safo, M K; Ku, W Y; Hsieh, S Y; Yuan, H S

1996-01-01

295

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

2010-09-11

296

Disruption of light-induced c-Fos immunoreactivity in the suprachiasmatic nuclei of chronic epileptic rats  

Microsoft Academic Search

Photic stimulation during specific day periods may induce Fos oncoprotein expression within the ventrolateral part of the suprachiasmatic nucleus (SCN) in the hypothalamus of rodents. This phenomenon appears to be a major molecular mechanism for environmental light\\/dark cycle entrainment of the mammalian circadian clock. Light-dependent synchronization of circadian rhythmicity may be disrupted in epilepsy, a chronic neurological disorder often associated

Emilio R. G. Sanabria; Fulvio A. Scorza; Zuner A. Bortolotto; Lineu S. Calderazzo-Filho; Esper A. Cavalheiro

1996-01-01

297

E6 and E7 variants of human papillomavirus-16 and -52 in Japan, the Philippines, and Vietnam.  

PubMed

Human papillomavirus (HPV) has several intragenotypic variants with different geographical and ethnic distributions. This study aimed to elucidate the distribution patterns of E6 and E7 (E6/E7) intragenotypic variants of HPV type 16 (HPV-16), which is most common worldwide, and HPV-52, which is common in Asian countries such as Japan, the Philippines, and Vietnam. In previous studies, genomic DNA samples extracted from cervical swabs were collected from female sex workers in these three countries and found to be positive for HPV-16 or HPV-52. Samples were amplified further for their E6/E7 genes using type-specific primers and analyzed genetically. Seventy-nine HPV-16 E6/E7 genes were analyzed successfully and grouped into three lineages: European (Prototype), European (Asian), and African-2. The prevalences of HPV-16 European (Prototype)/European (Asian) lineages were 19.4%/80.6% (n = 31) in Japan, 75.0%/20.8% (n = 24) in the Philippines, and 0%/95.8% (n = 24) in Vietnam. The 109 HPV-52 E6/E7 genes analyzed successfully were grouped into four lineages, A-D; the prevalences of lineages A/B/C/D were, respectively, 5.1%/92.3%/0%/2.6% in Japan (n = 39), 34.4%/62.5%/0%/3.1% in the Philippines (n = 32), and 15.8%/73.7%/7.9%/2.6% in Vietnam (n = 38). The distribution patterns of HPV-16 and HPV-52 lineages in these countries differed significantly (P < 0.000001 and P = 0.0048, respectively). There was no significant relationship between abnormal cervical cytology and either HPV-16 E6/E7 lineages or specific amino acid mutations, such as E6 D25E, E6 L83V, and E7 N29S. Analysis of HPV-16 and HPV-52 E6/E7 genes can be a useful molecular-epidemiological tool to distinguish geographical diffusion routes of these HPV types in Asia. PMID:23588734

Ishizaki, Azumi; Matsushita, Kaori; Hoang, Huyen Thi Thanh; Agdamag, Dorothy M; Nguyen, Cuong Hung; Tran, Vuong Thi; Sasagawa, Toshiyuki; Saikawa, Kunikazu; Lihana, Raphael; Pham, Hung Viet; Bi, Xiuqiong; Ta, Van Thanh; Van Pham, Thuc; Ichimura, Hiroshi

2013-06-01

298

The E7 proteins of low- and high-risk human papillomaviruses share the ability to target the pRB family member p130 for degradation.  

PubMed

High-risk human papillomaviruses (HPVs) (e.g., HPV-16) cause anogenital and head and neck cancers, and low-risk HPVs (e.g., HPV-6) cause benign hyperproliferative disease. The E7 protein of HPV-16 binds all retinoblastoma tumor suppressor protein (pRB) family members with higher affinity than HPV-6E7. The HPV-16 E7 protein has been reported to target pRB family members for degradation and to immortalize cells. Here we tested the hypothesis that the low-risk E7 protein has an intrinsic ability to decrease expression of pRB family members. First, we introduced a high-affinity pRB-binding site into HPV-6 E7 (6E7G22D) and showed that, in human foreskin keratinocytes, HPV-6 E7G22D decreased the level of pRB protein but not pRB mRNA. Second, we analyzed the ability of wild-type HPV-6 E7 to destabilize the other pRB family members, p107 and p130. HPV-6 E7, like HPV-16 E7, decreased the level of p130 protein. This decrease was inhibited by MG132, a proteasome inhibitor. Binding of HPV-6 E7 to p130 was necessary but not sufficient to decrease the level of p130. Furthermore, the destabilization of p130 correlated with a decrease in the expression of involucrin, a differentiation marker. We suggest that the shared activity of HPV-16 E7 and HPV-6 E7 to destabilize p130 and decrease or delay differentiation may be related to the role of E7 in the HPV life cycle. The added ability of HPV-16 E7 to regulate pRB and p107 may be related to oncogenic activity. PMID:16381817

Zhang, Benyue; Chen, Wei; Roman, Ann

2005-12-28

299

Recombined DNA vaccines encoding calreticulin linked to HPV6bE7 enhance immune response and inhibit angiogenic activity in B16 melanoma mouse model expressing HPV 6bE7 antigen  

Microsoft Academic Search

Calreticulin (CRT) has been reported to have an effect of upregulating MHC class I presentation as well as inhibiting angiogenesis in vitro and in vivo. Combination of dual mechanisms of enhanced immunogenicity of human papillomavirus (HPV) 6bE7 antigen and antiangiogenesis may be introduced in the strategy of vaccines against condyloma acuminatum (CA) resulting from HPV infection. Therefore, we constructed DNA

Ke-Jia Zhao; Hao Cheng; Ke-Jian Zhu; Yan Xu; Min-li Chen; Xing Zhang; Tao Song; Jun Ye; Qi Wang; Da-Fang Chen

2006-01-01

300

Structure of the retinoblastoma protein bound to adenovirus E1A reveals the molecular basis for viral oncoprotein inactivation of a tumor suppressor  

SciTech Connect

The adenovirus (Ad) E1A (Ad-E1A) oncoprotein mediates cell transformation, in part, by displacing E2F transcription factors from the retinoblastoma protein (pRb) tumor suppressor. In this study we determined the crystal structure of the pRb pocket domain in complex with conserved region 1 (CR1) of Ad5-E1A. The structure and accompanying biochemical studies reveal that E1A-CR1 binds at the interface of the A and B cyclin folds of the pRb pocket domain, and that both E1A-CR1 and the E2F transactivation domain use similar conserved nonpolar residues to engage overlapping sites on pRb, implicating a novel molecular mechanism for pRb inactivation by a viral oncoprotein.

Liu, Xin; Marmorstein, Ronen (UPENN)

2008-04-02

301

Interaction of cellular factors related to the Jun oncoprotein with the promoter of a replication-dependent hamster histone H3. 2 gene  

SciTech Connect

The promoter region of a replication-dependent histone H3.2 gene contains a putative DNA binding site for the Jun oncoprotein within a 32-nucleotide regulatory domain. The hamster sequence differs by one nucleotide from the AP-1 consensus sequence found in several promoters responsive to phorbol 12-myristate 13-acetate. The authors have identified the factors interacting with this region as 42- and 45-kDa proteins by DNA affinity chromatography, immunoblotting, and UV crosslinking. These proteins, which are candidates for conferring high-level expression to the histone promoter, share an antigenic epitope with the DNA-binding domain of Jun but diverge from it at the amino terminus. The interaction of these proteins with the promoter of a replication-dependent cellular gene provides evidence that members of the Jun oncoprotein family may play specific roles in the expression of genes essential for progression of the cell cycle.

Sharma, A.; Bos, T.J.; Pekkala-Flagan, A.; Vogt, P.K.; Lee, A.S. (Univ. of Southern California School of Medicine, Los Angeles (USA))

1989-01-01

302

Soluble ectodomain of c-erbB-2 oncoprotein in relation to tumour stage and grade in human renal cell carcinoma.  

PubMed Central

The soluble ectodomain of c-erbB-2 oncoprotein was measured using a sandwich enzyme immunoassay in sera from 184 patients with renal cell carcinoma before initiation of treatment. The median serum level was 2062 U ml(-1) (range 865-4905 U ml(-1)). Levels were unaffected by sex, age and renal function. An inverse relation between disease stage (P = 0.0017) and tumour grade (P = 0.0009) and the serum level of c-erbB-2 ectodomain was observed. Survival time for patients with serum levels above median level was significantly longer than for patients with lower levels (P = 0.003). In a multivariate analysis, c-erbB-2 oncoprotein lost its prognostic information, while tumour stage and tumour grade were identified as independent prognostic factors.

Rasmuson, T.; Grankvist, K.; Ljungberg, B.

1997-01-01

303

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

304

Human papillomavirus 16 L1-E7 chimeric virus like particles show prophylactic and therapeutic efficacy in murine model of cervical cancer.  

PubMed

Cervical cancer is found to be associated with human papillomavirus (HPV) infection, with HPV16 being the most prevalent. An effective vaccine against HPV can thus, be instrumental in controlling cervical cancer. An ideal HPV vaccine should aim to generate both humoral immune response to prevent new infection as well as cell-mediated immunity to eliminate established infection. In this study, we have generated a potential preventive and therapeutic candidate vaccine against HPV16. We expressed and purified recombinant HPV16 L1(?N26)-E7(?C38) protein in E. coli which was assembled into chimeric virus like particles (CVLPs) in vitro. These CVLPs were able to induce neutralizing antibodies and trigger cell-mediated immune response, in murine model of cervical cancer, exhibiting antitumor efficacy. Hence, this study has aimed to provide a vaccine candidate possessing both, prophylactic and therapeutic efficacy against HPV16 associated cervical cancer. PMID:22717329

Sharma, Chandresh; Dey, Bindu; Wahiduzzaman, Mohammed; Singh, Neeta

2012-06-17

305

The leukaemic oncoproteins Bcr-Abl and Tel-Abl (ETV6\\/Abl) have altered substrate preferences and activate similar intracellular signalling pathways  

Microsoft Academic Search

Inappropriate activation of Abl family kinases plays a crucial role in different human leukaemias. In addition to the well known oncoproteins p190Bcr-Abl and p210Bcr-Abl, Tel-Abl, a novel fusion protein resulting from a different chromosomal translocation, has recently been described. In this study, the kinase specificities of the Bcr-Abl and Tel-Abl proteins were compared to the physiological Abl family kinases c-Abl

Jan Voss; Guido Posern; Jürgen R Hannemann; Leanne M Wiedemann; Ali G Turhan; Hélène Poirel; Olivier A Bernard; Knut Adermann; Christian Kardinal; Stephan M Feller

2000-01-01

306

Structures of a Human Papillomavirus (HPV) E6 Polypeptide Bound to MAGUK Proteins: Mechanisms of Targeting Tumor Suppressors by a High-Risk HPV Oncoprotein  

Microsoft Academic Search

Human papillomavirus (HPV) E6 oncoprotein targets certain tumor suppressors such as MAGI-1 and SAP97\\/ hDlg for degradation. A short peptide at the C terminus of E6 interacts specifically with the PDZ domains of these tumor suppressors, which is a property unique to high-risk HPVs that are associated with cervical cancer. The detailed recognition mechanisms between HPV E6 and PDZ proteins

Yi Zhang; Jhimli Dasgupta; Runlin Z. Ma; Lawrence Banks; Miranda Thomas; Xiaojiang S. Chen

2007-01-01

307

Differential processing of let-7a precursors influences RRM2 expression and chemosensitivity in pancreatic cancer: role of LIN-28 and SET oncoprotein.  

PubMed

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

2013-01-15

308

CD8 T Cell Epitopes in HPV 16 E6 and E7 Proteins and Uses Thereof.  

National Technical Information Service (NTIS)

The present invention is directed to the examination of the pattern of immunodominant CD8 T cell epitopes in the E6 and E7 protein of Human Papillomavirus (HPV) and its further characterization in terms of its amino acid sequence and HLA restriction. Thes...

A. B. Moscicki K. H. Kim M. Nakagawa

2006-01-01

309

CTL Responses to a DNA Vaccine Encoding E7 Gene of Human Papillomavirus Type 16 from an Iranian Isolate  

Microsoft Academic Search

Background: Cervical cancer is the most prevalent tumor in developing countries and the second most frequent cancer among female population worldwide. Specific human papillomaviruses and, most notably, HPV types 16 and 18 are recognized as being caus- ally associated with cervical carcinomas. The early HPV type 16 genes, E6 and E7, di- rectly participate in the in vitro transformation of

Zahra Meshkat; Hoorieh Soleimanjahi; Mahmoud Mahmoudi; Zuhair Mohammad Hassan; Hessam Mirshahabi; Mojtaba Meshkat; Maryam Kheirandish

310

RNA polymerase II transcription is required for human papillomavirus type 16 E7- and hydroxyurea-induced centriole overduplication  

Microsoft Academic Search

Aberrant centrosome numbers are detected in virtually all human cancers where they can contribute to chromosomal instability by promoting mitotic spindle abnormalities. Despite their widespread occurrence, the molecular mechanisms that underlie centrosome amplification are only beginning to emerge. Here, we present evidence for a novel regulatory circuit involved in centrosome overduplication that centers on RNA polymerase II (pol II). We

A Duensing; Y Liu; N Spardy; K Bartoli; M Tseng; J-A Kwon; X Teng; S Duensing

2007-01-01

311

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

PubMed Central

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

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

2010-01-01

312

Enhancement of human papillomavirus (HPV) type 16 E6 and E7-specific T-cell immunity in healthy volunteers through vaccination with TA-CIN, an HPV16 L2E7E6 fusion protein vaccine  

Microsoft Academic Search

TA-CIN is a vaccine that comprises the human papillomavirus (HPV) type 16 L2, E6 and E7 as a single fusion protein. In a mouse model, TA-CIN effectively prevented outgrowth of HPV16-positive tumour cells. To assess the safety and immunogenicity of TA-CIN, a dose escalating (26, 128, 533?g), double blind and placebo-controlled phase I study was conducted in 40 healthy volunteers.

A de Jong; T O’Neill; A. Y Khan; K. M. C Kwappenberg; S. E Chisholm; N. R Whittle; J. A Dobson; L. C Jack; J St Clair Roberts; R Offringa; S. H van der Burg; J. K Hickling

2002-01-01

313

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

314

Inactivation of YAP oncoprotein by the Hippo pathway is involved in cell contact inhibition and tissue growth control  

PubMed Central

The Hippo pathway plays a key role in organ size control by regulating cell proliferation and apoptosis in Drosophila. Although recent genetic studies have shown that the Hippo pathway is regulated by the NF2 and Fat tumor suppressors, the physiological regulations of this pathway are unknown. Here we show that in mammalian cells, the transcription coactivator YAP (Yes-associated protein), is inhibited by cell density via the Hippo pathway. Phosphorylation by the Lats tumor suppressor kinase leads to cytoplasmic translocation and inactivation of the YAP oncoprotein. Furthermore, attenuation of this phosphorylation of YAP or Yorkie (Yki), the Drosophila homolog of YAP, potentiates their growth-promoting function in vivo. Moreover, YAP overexpression regulates gene expression in a manner opposite to cell density, and is able to overcome cell contact inhibition. Inhibition of YAP function restores contact inhibition in a human cancer cell line bearing deletion of Salvador (Sav), a Hippo pathway component. Interestingly, we observed that YAP protein is elevated and nuclear localized in some human liver and prostate cancers. Our observations demonstrate that YAP plays a key role in the Hippo pathway to control cell proliferation in response to cell contact.

Zhao, Bin; Wei, Xiaomu; Li, Weiquan; Udan, Ryan S.; Yang, Qian; Kim, Joungmok; Xie, Joe; Ikenoue, Tsuneo; Yu, Jindan; Li, Li; Zheng, Pan; Ye, Keqiang; Chinnaiyan, Arul; Halder, Georg; Lai, Zhi-Chun; Guan, Kun-Liang

2007-01-01

315

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

316

Altered nuclear co-factor switching in retinoic resistant variants of the PML-RAR? oncoprotein of acute promyelocytic leukemia†  

PubMed Central

Acute Promyelocytic Leukemia (APL) results from a reciprocal translocation that fuses the gene for the PML tumor suppressor to that encoding the retinoic acid receptor alpha (RAR?). The resulting PML-RAR? oncogene product interferes with multiple regulatory pathways associated with myeloid differentiation, including normal PML and RAR? functions. The standard treatment for APL includes anthracycline-based chemotherapeutic agents plus the RAR? agonist all-trans retinoic acid (ATRA). Relapse, which is often accompanied by ATRA resistance, occurs in an appreciable frequency of treated patients. One potential mechanism suggested by model experiments featuring the selection of ATRA resistant APL cell lines involves ATRA resistant versions of the PML-RAR? oncogene, where the relevant mutations localize to the RAR? ligand-binding domain (LBD). Such mutations may act by compromising agonist binding, but other mechanisms are possible. Here, we studied the molecular consequence of ATRA resistance by use of circular dichroism, protease resistance, and fluorescence anisotropy assays employing peptides derived from the NCOR nuclear co-repressor and the ACTR nuclear co-activator. The consequences of the mutations on global structure and co-factor interaction functions were assessed quantitatively, providing insights into the basis of agonist resistance. Attenuated co-factor switching and increased protease resistance represent features of the LBDs of ATRA-resistant PML-RAR?, and these properties may be recapitulated in the full-length oncoproteins.

Farris, Mindy; Lague, Astrid; Manuelyan, Zara; Statnekov, Jacob; Francklyn, Christopher

2011-01-01

317

Bovine papillomavirus type 1 oncoprotein E5 inhibits equine MHC class I and interacts with equine MHC I heavy chain.  

PubMed

Bovine papillomavirus type 1 is one of the aetiological agents of equine sarcoids. The viral major oncoprotein E5 is expressed in virtually all sarcoids, sarcoid cell lines and in vitro-transformed equine fibroblasts. To ascertain whether E5 behaves in equine cells as it does in bovine cells, we introduced the E5 open reading frame into fetal equine fibroblasts (EqPalF). As observed in primary bovine fibroblasts (BoPalF), E5 by itself could not immortalize EqPalF and an immortalizing gene, such as human telomerase (hTERT/hT), was required for the cells to survive selection. The EqPalF-hT-1E5 cells were morphologically transformed, elongated with many pseudopodia and capable of forming foci. Equine major histocompatibility complex class I (MHC I) was inhibited in these cells at least at two levels: transcription of MHC I heavy chain was inhibited and the MHC I complex was retained in the Golgi apparatus and prevented from reaching the cell surface. We conclude that, as in bovine cells and tumours, E5 is a player in the transformation of equine cells and the induction of sarcoids, and a potential major cause of MHC I downregulation and hence poor immune clearance of tumour cells. PMID:19675187

Marchetti, Barbara; Gault, Elisabeth A; Cortese, Marc S; Yuan, ZhengQiang; Ellis, Shirley A; Nasir, Lubna; Campo, M Saveria

2009-08-12

318

Identification of relevant conformational epitopes on the HER2 oncoprotein by using Large Fragment Phage Display (LFPD).  

PubMed

We developed a new phage-display based approach, the Large Fragment Phage Display (LFPD), that can be used for mapping conformational epitopes on target molecules of immunological interest. LFPD uses a simplified and more effective phage-display approach in which only a limited set of larger fragments (about 100 aa in length) are expressed on the phage surface. Using the human HER2 oncoprotein as a target, we identified novel B-cell conformational epitopes. The same homologous epitopes were also detected in rat HER2 and all corresponded to the epitopes predicted by computational analysis (PEPITO software), showing that LFPD gives reproducible and accurate results. Interestingly, these newly identified HER2 epitopes seem to be crucial for an effective immune response against HER2-overexpressing breast cancers and might help discriminating between metastatic breast cancer and early breast cancer patients. Overall, the results obtained in this study demonstrated the utility of LFPD and its potential application to the detection of conformational epitopes on many other molecules of interest, as well as, the development of new and potentially more effective B-cell conformational epitopes based vaccines. PMID:23555577

Gabrielli, Federico; Salvi, Roberto; Garulli, Chiara; Kalogris, Cristina; Arima, Serena; Tardella, Luca; Monaci, Paolo; Pupa, Serenella M; Tagliabue, Elda; Montani, Maura; Quaglino, Elena; Stramucci, Lorenzo; Curcio, Claudia; Marchini, Cristina; Amici, Augusto

2013-03-28

319

ETO protein of t(8;21) AML is a corepressor for Bcl-6 B-cell lymphoma oncoprotein.  

PubMed

The multiplicity of transcription factors involved in hematologic malignancies suggests a complicated scenario in which many different molecular mechanisms lead to malignant transformation. We hypothesized that some of these proteins might physically and functionally interact and thus mechanistically link different diseases. The ETO protein of t(8;21) acute myeloid leukemia (AML) is an excellent candidate as a common factor because it is normally expressed in human hematopoietic cells, it binds to histone deacetylases (HDACs), and it interacts with the PLZF protein of t(11;17) acute promyelocytic leukemia. To determine whether ETO functionally links a broader range of disease entities, we asked whether ETO forms a complex with the Bcl-6 oncoprotein of B-cell lymphomas. We found that ETO and Bcl-6 are coexpressed in normal and malignant lymphoid tissue, where they interact and colocalize in nuclear speckles. ETO binds to the fourth zinc finger of Bcl-6, enhances Bcl-6 repression of artificial and endogenous genes in an HDAC-dependent manner, and forms a complex with Bcl-6 on the promoters of its endogenous target genes in B-cell lymphoma cells. Therefore, ETO is a bona fide corepressor that links the transcriptional pathogenesis of acute leukemias and B-cell lymphomas and offers a compelling target for transcriptional therapy of hematologic malignancies. PMID:14551142

Chevallier, Nathalie; Corcoran, Connie M; Lennon, Christine; Hyjek, Elizabeth; Chadburn, Amy; Bardwell, Vivian J; Licht, Jonathan D; Melnick, Ari

2003-10-09

320

The Ewing's sarcoma oncoprotein EWS\\/FLI induces a p53-dependent growth arrest in primary human fibroblasts  

Microsoft Academic Search

Ewing's sarcoma is associated with a fusion between the EWS and FLI1 genes, forming an EWS\\/FLI fusion protein. We developed a system for the identification of cooperative mutations in this tumor through expression of EWS\\/FLI in primary human fibroblasts. Gene expression profiling demonstrated that this system recapitulates many features of Ewing's sarcoma. EWS\\/FLI-expressing cells underwent growth arrest, suggesting that growth

Stephen L. Lessnick; Caroline S. Dacwag; Todd R. Golub

2002-01-01

321

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.

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

2008-01-01

322

X-linked agammaglobulinemia and the red blood cell determinants Xg and 12E7 are not closely linked  

Microsoft Academic Search

Studies on the segregation of the red blood cell determinant Xg in 12 families with X-linked inheritance of agammaglobulinemia (XLA) in 3–4 generations suggested linkage of Xg with XLA. One extensive pedigree of a Dutch family with XLA in eight generations was investigated for Xg and the quantitative polymorphism 12E7. LIPED analysis indicated linkage disproven up to 25cM distance within

E. J. B. M. Mensink; J. D. L. Schot; P. Tippett; J. Ott; R. K. B. Schuurman

1984-01-01

323

Expression of apoptosis-related oncoproteins and modulation of apoptosis by caffeine in human leukemic cells  

Microsoft Academic Search

We investigated the modulation of radio- and chemoresistance by caffeine and mechanisms of resistance in human leukemic cell lines and mononuclear cells from 18 leukemic patients. Caffeine synergistically potentiated cytotoxicity and apoptosis induced by ionizing radiation or carboplatin (CPt), but attenuated induction of apoptosis by daunorubicin (DNR) in KG-1a cells. Since caffeine released irradiated as well as DNR-treated KG-1a cells

T. Efferth; U. Fabry; P. Glatte; R. Osieka

1995-01-01

324

Photochemical destruction of the Bcl2 oncoprotein during photodynamic therapy with the phthalocyanine photosensitizer Pc 4  

Microsoft Academic Search

Photodynamic therapy (PDT), utilizing a photosensitizer and visible light, causes localized oxidative damage. With the mitochondrial photosensitizer Pc 4, PDT induces apoptosis, yet its molecular targets are not known. Here, the anti-apoptotic protein Bcl-2 is shown to be highly sensitive to PDT, as judged on Western blots by the disappearance of anti-Bcl-2-reactive material from the position of the native 26

Liang-yan Xue; Song-mao Chiu; Nancy L Oleinick

2001-01-01

325

STI571 inactivation of the gastrointestinal stromal tumor c-KIT oncoprotein: biological and clinical implications  

Microsoft Academic Search

Mutations in the c-KIT receptor occur somatically in many sporadic Gastrointestinal Stromal Tumors (GIST), and similar mutations have been identified at the germline level in kindreds with multiple GISTs. These mutations activate the tyrosine kinase activity of c-KIT and induce constitutive signaling. To investigate the function of activated c-KIT in GIST, we established a human GIST cell line, GIST882, which

David A Tuveson; Nicholas A Willis; Tyler Jacks; James D Griffin; Samuel Singer; Christopher DM Fletcher; Jonathan A Fletcher; George D Demetri

2001-01-01

326

Transformation of hematopoietic cells by the Ski oncoprotein involves repression of retinoic acid receptor signaling.  

PubMed

The Ski oncogene has dramatic effects on the differentiation of several different cell types. It induces the differentiation of quail embryo cells into myoblasts and arrests the differentiation of chicken hematopoietic cells. The mechanism that Ski uses to carry out these disparate biological activities is unknown. However, we were struck by the similarity of these effects to those of certain members of the nuclear hormone receptor family. Both Ski and the thyroid hormone receptor-derived oncogene v-ErbA can arrest the differentiation of avian erythroblasts, and v-Ski-transformed avian multipotent progenitor cells resemble murine hematopoietic cells that express a dominant-negative form of the retinoic acid receptor, RARalpha. In this paper, we have tested the hypothesis that v-Ski and its cellular homologue c-Ski exert their effects by interfering with nuclear hormone receptor-induced transcription. We demonstrate that Ski associates with the RAR complex and can repress transcription from a retinoic acid response element. The physiological significance of this finding is demonstrated by the ability of high concentrations of a RARalpha-specific ligand to abolish v-Ski-induced transformation of the multipotent progenitors. These results strongly suggest that the ability of Ski to alter cell differentiation is caused in part by the modulation of RAR signaling pathways. PMID:9736711

Dahl, R; Kieslinger, M; Beug, H; Hayman, M J

1998-09-15

327

Inhibition of cervical cancer cell growth by human papillomavirus virus-like particles packaged with human papillomavirus oncoprotein short hairpin RNAs  

Microsoft Academic Search

Overexpression of human papillomavirus (HPV E6 and HPV E7) oncogenes in human cervical cells results in the development of cancer, and E6 and E7 proteins are therefore targets for preventing cervical cancer progres- sion. Here, we describe the silencing of E6 and E7 expression in cervical carcinoma cells by RNA interfer- ence. In order to increase the efficacy of the

Latifa Bousarghin; Antoine Touze; Guillaume Gaud; Sophie Iochmann; Eva Alvarez; Pascale Reverdiau; Julien Gaitan; Marie-Lise Jourdan; Pierre-Yves Sizaret; Pierre L. Coursaget

2009-01-01

328

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.

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

2011-01-01

329

Transcriptional Activation of the Telomerase hTERT Gene by Human Papillomavirus Type 16 E6 Oncoprotein  

Microsoft Academic Search

The E6 and E7 oncogenes of human papillomavirus type 16 (HPV-16) are sufficient for the immortalization of human genital keratinocytes in vitro. The products of these viral genes associate with p53 and pRb tumor suppressor proteins, respectively, and interfere with their normal growth-regulatory functions. The HPV-16 E6 protein has also been shown to increase the telomerase enzyme activity in primary

TIM VELDMAN; IZUMI HORIKAWA; J. CARL BARRETT; RICHARD SCHLEGEL

2001-01-01

330

Acetylation at lysine 346 controls the transforming activity of the HTLV-1 Tax oncoprotein in the Rat-1 fibroblast model  

PubMed Central

Background Transformation by the Tax oncoprotein of the human T cell leukemia virus type 1 (HTLV-1) is governed by actions on cellular regulatory signals, including modulation of specific cellular gene expression via activation of signaling pathways, acceleration of cell cycle progression via stimulation of cyclin-dependent kinase activity leading to retinoblastoma protein (pRb) hyperphosphorylation and perturbation of survival signals. These actions control early steps in T cell transformation and development of Adult T cell leukemia (ATL), an aggressive malignancy of HTLV-1 infected T lymphocytes. Post-translational modifications of Tax by phosphorylation, ubiquitination, sumoylation and acetylation have been implicated in Tax-mediated activation of the NF-?B pathway, a key function associated with Tax transforming potential. Results In this study, we demonstrate that acetylation at lysine K346 in the carboxy-terminal domain of Tax is modulated in the Tax nuclear bodies by the acetyltransferase p300 and the deacetylases HDAC5/7 and controls phosphorylation of the tumor suppressor pRb by Tax-cyclin D3-CDK4-p21CIP complexes. This property correlates with the inability of the acetylation deficient K346R mutant, but not the acetylation mimetic K346Q mutant, to promote anchorage-independent growth of Rat-1 fibroblasts. By contrast, acetylation at lysine K346 had no effects on the ability of Tax carboxy-terminal PDZ-binding domain to interact with the tumor suppressor hDLG. Conclusions The identification of the acetyltransferase p300 and the deacetylase HDAC7 as enzymes modulating Tax acetylation points to new therapeutic targets for the treatment of HTLV-1 infected patients at risk of developing ATL.

2013-01-01

331

DNA binding-independent transcriptional activation of the vascular endothelial growth factor gene (VEGF) by the Myb oncoprotein  

SciTech Connect

Myb is a key transcription factor that can regulate proliferation, differentiation, and apoptosis, predominantly in the haemopoietic system. Abnormal expression of Myb is associated with a number of cancers, both haemopoietic and non-haemopoietic. In order to better understand the role of Myb in normal and tumorigenic processes, we undertook a cDNA array screen to identify genes that are regulated by this factor. In this way, we identified the gene encoding vascular endothelial growth factor (VEGF) as being potentially regulated by the Myb oncoprotein in myeloid cells. To determine whether this was a direct effect on VEGF gene transcription, we examined the activity of the murine VEGF promoter in the presence of either wild-type (WT) or mutant forms of Myb. It was found that WT Myb was able to activate the VEGF promoter and that a minimal promoter region of 120 bp was sufficient to confer Myb responsiveness. Surprisingly, activation of the VEGF promoter was independent of DNA binding by Myb. This was shown by the use of DNA binding-defective Myb mutants and by mutagenesis of a potential Myb-binding site in the minimal promoter. Mutation of Sp1 sites within this region abolished Myb-mediated regulation of a reporter construct, suggesting that Myb DNA binding-independent activation of VEGF expression occurs via these Sp1 binding elements. Regulation of VEGF production by Myb has implications for the potential role of Myb in myeloid leukaemias and in solid tumours where VEGF may be functioning as an autocrine growth factor.

Lutwyche, Jodi K. [Division of Human Immunology and Hanson Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA 5000 (Australia); Keough, Rebecca A. [Division of Human Immunology and Hanson Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA 5000 (Australia)]. E-mail: rebecca.keough@adelaide.edu.au; Hunter, Julie [Division of Human Immunology and Hanson Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA 5000 (Australia); Coles, Leeanne S. [Division of Human Immunology and Hanson Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA 5000 (Australia); Gonda, Thomas J. [Division of Human Immunology and Hanson Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA 5000 (Australia)]. E-mail: tgonda@cicr.uq.edu.au

2006-06-16

332

Oncogenic HPV infection interrupts the expression of tumor-suppressive miR-34a through viral oncoprotein E6  

PubMed Central

MicroRNAs (miRNA) play pivotal roles in controlling cell proliferation and differentiation. Aberrant miRNA expression in human is becoming recognized as a new molecular mechanism of carcinogenesis. However, the causes for alterations in miRNA expression remain largely unknown. Infection with oncogenic human papillomavirus types 16 (HPV16) and 18 (HPV18) can lead to cervical and other ano-genital cancers. Here, we have demonstrated that cervical cancer tissues and cervical cancer-derived cell lines containing oncogenic HPVs display reduced expression of tumor-suppressive miR-34a. The reduction of miR-34a expression in organotypic tissues derived from HPV-containing primary human keratinocytes correlates with the early productive phase and is attributed to the expression of viral E6, which destabilizes the tumor suppressor p53, a known miR-34a transactivator. Knockdown of viral E6 expression in HPV16+ and HPV18+ cervical cancer cell lines by siRNAs leads to an increased expression of p53 and miR-34a and accumulation of miR-34a in G0/G1 phase cells. Ectopic expression of miR-34a in HPV18+ HeLa cells and HPV? HCT116 cells results in a substantial induction of cell growth retardation and a moderate cell apoptosis. Together, this is the first time a viral oncoprotein has been shown to regulate cellular miRNA expression. Our data have provided new insights into mechanisms by which high-risk HPVs contribute to the development of cervical cancer.

Wang, Xiaohong; Wang, Hsu-Kun; McCoy, J. Philip; Banerjee, Nilam S.; Rader, Janet S.; Broker, Thomas R.; Meyers, Craig; Chow, Louise T.; Zheng, Zhi-Ming

2009-01-01

333

Immunization of protein HPV16 E7 in fusion with mouse HSP70 inhibits the growth of TC-1 cells in tumor bearing mice.  

PubMed

Human papillomavirus (HPV) 16 is the primary etiologic agent of cervical cancer. Most HPV16 therapeutic vaccines target E7 protein which is consistently expressed in tumor cells. In this study, we cloned mouse autologous heat shock protein 70 (mHSP70) gene from mouse liver cells and then expressed mHSP70 and fused HPV16 E7-mHSP70 (E7 at the N-terminus and mHSP70 at the C-terminus) proteins in E. coli. Then we investigated the inhibition of TC-1 cell growth by using the E7-expressing murine tumor cell line, TC-1, as a model of cervical cancer. In this model, mice were immunized with the fusion protein of E7-mHSP70 without any adjuvant. The results showed that prophylactic immunization of E7-mHSP70 protected mice against challenge with TC-1 cells. In addition, therapeutic immunization with E7-mHSP70 could inhibit TC-1 tumor growth on lungs. Our study demonstrated that immunization with E7-mHSP70 protein without any adjuvant could generate anti-tumor effect in mice challenged with TC-1 cells. PMID:21722685

Li, Yan-Li; Liu, Jie; Liu, Jian-Ning; Zhang, Jing

2011-06-29

334

Inhibition of cervical cancer cell growth in vitro and in vivo by lentiviral-vector mediated shRNA targeting the common promoter of HPV16 E6 and E7 oncogenes.  

PubMed

Deregulated expression of high-risk human papillomavirus oncogenes (E6 and E7) is a pivotal event for pathogenesis and progression in cervical cancer. Both viral oncogenes are therefore regarded as ideal therapeutic targets. Small interfering RNAs (siRNA) or double-stranded RNAs can knock down target genes effectively through siRNA-induced transcriptional gene silencing (TGS). Here, we established lentiviral-vector mediated shRNA (LV-shRNA) targeting common promoter of HPV16 E6/E7 and targeting E6 transcript, transduced the lentiviral construct into cervical HPV16-positive cell lines Siha and Caski, then selected and established stably transduced monoclonal cell lines. The results showed that LV-shRNA targeting promoter, as well as targeting E6 transcript, effectively knocked down E6 and E7 expression, resulted in accumulation of p53 and pRB protein and decrease of MCM7 and p16 protein, and consequently remarkably reduced the abilities of proliferation and invasiveness of cervical cancers cells in vitro. Then we inoculated subcutaneously those monoclonal cells into nude mice to establish the transplanted tumor animal models, and found dramatically inhibited tumorigenesis and growth, as well as prolonged survival time of mice incubated by cells with LV-shRNA targeting promoter and E6 transcript. Our results may provide evidence for application of LV-shRNA targeting HR-HPV key oncogenes, as a new treatment strategy, in cervical and other HPV-associated cancer therapy. PMID:23523766

Zhou, Jiansong; Li, Baohua; Peng, Chanjuan; Wang, Fenfen; Fu, Zhiqin; Zhou, Caiyun; Hong, Die; Ye, Feng; Lü, Weiguo; Xie, Xing

2013-03-21

335

Arsenic trioxide controls the fate of the PML-RARalpha oncoprotein by directly binding PML.  

PubMed

Arsenic, an ancient drug used in traditional Chinese medicine, has attracted worldwide interest because it shows substantial anticancer activity in patients with acute promyelocytic leukemia (APL). Arsenic trioxide (As2O3) exerts its therapeutic effect by promoting degradation of an oncogenic protein that drives the growth of APL cells, PML-RARalpha (a fusion protein containing sequences from the PML zinc finger protein and retinoic acid receptor alpha). PML and PML-RARalpha degradation is triggered by their SUMOylation, but the mechanism by which As2O3 induces this posttranslational modification is unclear. Here we show that arsenic binds directly to cysteine residues in zinc fingers located within the RBCC domain of PML-RARalpha and PML. Arsenic binding induces PML oligomerization, which increases its interaction with the small ubiquitin-like protein modifier (SUMO)-conjugating enzyme UBC9, resulting in enhanced SUMOylation and degradation. The identification of PML as a direct target of As2O3 provides new insights into the drug's mechanism of action and its specificity for APL. PMID:20378816

Zhang, Xiao-Wei; Yan, Xiao-Jing; Zhou, Zi-Ren; Yang, Fei-Fei; Wu, Zi-Yu; Sun, Hong-Bin; Liang, Wen-Xue; Song, Ai-Xin; Lallemand-Breitenbach, Valérie; Jeanne, Marion; Zhang, Qun-Ye; Yang, Huai-Yu; Huang, Qiu-Hua; Zhou, Guang-Biao; Tong, Jian-Hua; Zhang, Yan; Wu, Ji-Hui; Hu, Hong-Yu; de Thé, Hugues; Chen, Sai-Juan; Chen, Zhu

2010-04-01

336

Functionally distinct human marrow stromal cell lines immortalized by transduction with the human papilloma virus E6/E7 genes.  

PubMed

A replication-defective recombinant retrovirus containing the human papilloma virus E6/E7 genes (LXSN-16 E6E7) was used to immortalize stromal cells from human marrow. The E6/E7 gene products interfere with the function of tumor-suppressor proteins p53 and Rb, respectively, thereby preventing cell cycle arrest without causing significant transformation. Twenty-seven immortalized clones designated HS-1 to HS-27 were isolated, four of which are characterized in this report. Two cell lines, HS-5 and HS-21, appear to be fibroblastoid and secrete significant levels of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage-CSF (GM-CSF), macrophage-CSF (M-CSF), Kit ligand (KL), macrophage-inhibitory protein-1 alpha, interleukin-6 (IL-6), IL-8, and IL-11. However, only HS-5 supports proliferation of hematopoietic progenitor cells when cocultured in serum-deprived media with no exogenous factors. Conditioned media (CM) from HS-5 promotes growth of myeloid colonies to significantly greater extent than a cocktail of recombinant factors containing 10 ng/mL of IL-1, IL-3, IL-6, G-CSF, GM-CSF, and KL and 3 U of erythropoietin (Epo). Two additional clones, HS-23 and HS-27, resemble "blanket" cells, with an epithelioid morphology, and are much larger, broader, and flatter when compared with HS-5 and HS-21. These lines secrete low levels of growth factors and do not support proliferation of isolated progenitor cells in cocultures. CM from HS-23 and HS-27 also fail to support growth of myeloid colonies. Both HS-23 and HS-27 express relatively high levels of VCAM-1, yet HS-27 is the only line that supports the formation of "cobblestone" areas by isolated CD34+38lo cells. We hypothesize that HS-5, HS-21, HS-23, and HS-27 represent functionally distinct components of the marrow microenvironment. PMID:7849321

Roecklein, B A; Torok-Storb, B

1995-02-15

337

Src-Induced Disassembly of Adherens Junctions Requires Localized Phosphorylation and Degradation of the Rac Activator Tiam1  

Microsoft Academic Search

SUMMARY The Rac activator Tiam1 is required for adherens junction (AJ) maintenance, and its depletion results in AJ disassembly. Conversely, the oncoprotein Src potently induces AJ disassembly and epithelial- mesenchymal transition (EMT). Here, we show that Tiam1 is phosphorylated on Y384 by Src. This occurs predominantly at AJs, is required for Src-induced AJ disassembly and cell migration, and creates a

Simon A. Woodcock; Claire Rooney; Michalis Liontos; Yvonne Connolly; Vassilis Zoumpourlis; Anthony D. Whetton; Vassilis G. Gorgoulis; Angeliki Malliri

2009-01-01

338

Adenoviral p53 effects and cell-specific E7 protein–protein interactions of human cervical cancer cells  

Microsoft Academic Search

We investigated the time-course tumor growth suppression effects of recombinant adenovirus expressing p53 on human cervical cancer cells and cell-specific E7 protein–protein interactions in cell lysates using surface plasmon resonance (SPR) biosensor. Six HPV-infected human cervical cancer cell lines (HPV 16-positive cells, CaSki and SiHa cells; HPV 18-positive cells, HeLa and HeLaS3 cells; and HPV negative C33A and HT3 cells)

Jeong-Woo Choi; Woong Shick Ahn; Su Mi Bae; Doo-Bong Lee; Yong-Wan Kim

2005-01-01

339

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.

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

2012-01-01

340

Association of the viral oncoprotein STP-C488 with cellular ras.  

PubMed Central

The STP-C488 oncogene of herpesvirus saimiri has transforming activity independent of the rest of the viral genome. We now demonstrate that STP-C488 associates with cellular ras in transformed cells. Mutations that disrupted this association with ras disrupted the transforming ability of the STP-C488 oncogene. Binding assays showed that STP-C488 was capable of competing with raf-1 for binding to ras. Expression of STP-C488 activated the ras signaling pathway as evidenced by a two- to fourfold increase in the ratio of ras-GTP to ras-GDP and by the constitutive activation of mitogen-activated protein kinase. Consistent with an activation of signaling through ras, STP-C488 expression induced ras-dependent neurite outgrowth in PC12 cells. STP-C488 is the first virus-encoded protein shown to achieve oncogenic transformation via association with cellular ras.

Jung, J U; Desrosiers, R C

1995-01-01

341

The oncoprotein LMO3 interacts with calcium- and integrin-binding protein CIB.  

PubMed

The protein LMO3 belongs to the LIM only (LMO) group of transcriptional regulators, which act as molecular adaptors for protein-protein interactions. However, little is known about its interactive proteins and functions. Evaluating LMO3 in a yeast two-hybrid screen, we identified the calcium- and integrin-binding protein CIB as an LMO3-binding protein, which binds via the second LIM domain (LIM2) of LMO3. Cotransfection of LMO3 and CIB resulted in a shift in LMO3 protein from the nucleus to the cytoplasm. In functional assays, LMO3 induced C8 astrocyte proliferation was suppressed by the overexpression of CIB. This study demonstrates one function for LMO3 in C8 cells and suggests that one role of the CIB/LMO3 complex is to inhibit cell proliferation. PMID:19236851

Hui, Ling; Ji, Chaoneng; Hui, Bin; Lv, Tongde; Ha, Xiaoqin; Yang, Jinsheng; Cai, Wenqin

2009-02-21

342

ABL-fusion oncoproteins activate multi-pathway of DNA repair: role in drug resistance?  

PubMed

Chromosomal translocations of tyrosine kinase c-ABL gene from chromosome 9 may generate oncogenic kinases exhibiting constitutive tyrosine kinase activity. Recently, we have shown that ABL-fusion oncogenic tyrosine kinases, BCR/ABL and TEL/ABL, specific to hematopoietic malignances, induced resistance to DNA-damaging agents. To elucidate the role of DNA repair in this phenomenon we examined the capacity of murine BaF3 lymphoid cells and their TEL/ABL-transformed counterparts to repair DNA lesions caused by gamma- and UV-radiations and the anti-cancer drug, idarubicin. TEL/ABL-transformed cells displayed resistance to these DNA damaging agents as evaluated by MTT assay and the survival advantage was associated with an accelerated kinetics of DNA repair as measured by the alkaline comet assay. Deoxyribonucleosides (dNTPs) supplementation of the repair medium further stimulated DNA repair and the effect was specific to the DNA damage agent used in the experiment but only the transformed cells displayed this feature. A variety of damages induced imply the multi-pathway of DNA repair involved. We also examined the capability of BCR/ABL-fusion to modulate the repair of oxidative lesions, considered as a major side effect of various anti-cancer drugs including idarubicin and radiation. Employing the free radical scavenger alpha-phenyl-N-tert-butyl nitrone (PBN, a spin trap) and DNA repair enzymes: endonuclease III (EndoIII) that nicks DNA at sites of oxidized bases, we found that BCR/ABL-transformed cells repaired oxidative DNA lesions more effectively than control cells. Our results suggest, that oncogenic ABL-dependent stimulation of DNA repair may contribute to the cell resistance to genotoxic treatment. PMID:14987801

Majsterek, I; Slupianek, A; Hoser, G; Skórski, T; Blasiak, J

2004-01-01

343

Cervical cancer screening: which HPV test should be used-L1 or E6/E7?  

PubMed

Cervical cancer can and should be a historical disease. The reality, however, is that every year more than half a million women are diagnosed with cervical cancer and a quarter of a million die of this disease. The causal factor for cervical cancer is a persistent HPV infection and therefore a vaccine was developed: prophylactic HPV vaccination will reduce cervical cancer by 70%. Screening based on cytology will miss more than 40% of the abnormalities. The introduction of vaccination should lead to the reintroduction of cervical cancer screening based on HPV detection. Primary HPV screening followed by cytology will detect almost all abnormalities. Not all HPV tests, however, are the same! Clinicians are generally not aware that there is a huge difference among HPV tests. If a low grade lesion progresses to a high grade or invasive cancer, their HPV is likely to integrate. During integration L1 expression can be lost, but E6/E7 expression will always remain present. If the viral HPV is completely integrated then a L1 test looking for only L1 expression will miss this (pre)cancer, while the E6/E7 test will not miss it. HPV tests used in cervical cancer screening should be based on the early (E) and the late (L) genes in order not to miss the abnormality. PMID:23932300

Tjalma, W A A; Depuydt, C E

2013-08-06

344

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

2008-11-27

345

A novel, broad spectrum therapeutic HPV vaccine targeting the E7 proteins of HPV16, 18, 31, 45 and 52 that elicits potent E7-specific CD8T cell immunity and regression of large, established, E7-expressing TC-1 tumors.  

PubMed

Persistent infection by high risk genotypes of human papillomavirus (HPV) is the cause of cervical cancer, which remains one of the most common cancers among women worldwide. In addition, there is a growing appreciation that high risk HPVs are associated with a number of other cancers including anogenital cancers as well as a subset of head and neck cancers. Recently, prophylactic HPV vaccines targeting the two most prevalent high risk HPVs (HPV16 and HPV18) have been deployed in large-scale vaccination campaigns. However, the extent to which these prophylactic vaccines confer protection against other high risk HPV genotypes is largely unknown and prophylactic vaccines have been shown to be ineffective against pre-existing infection. Thus there continues to be an urgent need for effective therapeutic vaccines against HPV. The E7 protein of HPV16 has been widely studied as a target for therapeutic vaccines in HPV-associated cancer settings because HPV16 is the most prevalent of the high risk HPV genotypes. However, HPV16 accounts for only about 50% of cervical cancers and there are at least 15 other high risk HPVs that are known to be oncogenic. We have developed a novel, broad-spectrum, therapeutic vaccine (Pentarix) directed at the E7 proteins from five of the most prevalent high-risk genotypes of HPV worldwide (HPV16, 18, 31, 45 and 52) that together account for more than 80% of all HPV-associated cancers. Pentarix is a recombinant protein-based vaccine that elicits strong, multi-genotype specific CD8 T cell immunity when administered to mice in combination with adjuvants comprised of agonists of the TLR3 or TLR9 family of innate immune receptors. Furthermore, large, established E7-expressing TC-1 tumors undergo rapid and complete regression after therapeutic vaccination of mice with Pentarix. Together, these data suggest that Pentarix may be of clinical value for patients with E7-positive, HPV-associated precancerous lesions or malignant disease. PMID:21816200

Wick, Darin A; Webb, John R

2011-08-02

346

Differential transforming activity of the retroviral Tax oncoproteins in human T lymphocytes.  

PubMed

Human T cell leukemia virus type 1 and type 2 (HTLV-1 and -2) are two closely related retroviruses. HTLV-1 causes adult T cell leukemia and lymphoma, whereas HTLV-2 infection is not etiologically linked to human disease. The viral genomes of HTLV-1 and -2 encode highly homologous transforming proteins, Tax-1 and Tax-2, respectively. Tax-1 is thought to play a central role in transforming CD4+ T lymphocytes. Expression of Tax-1 is crucial for promoting survival and proliferation of virally infected human T lymphocytes and is necessary for initiating HTLV-1-mediated oncogenesis. In transgenic mice and humanized mouse model, Tax-1 has proven to be leukemogenic. Although Tax-1 is able to efficiently transform rodent fibroblasts and to induce lymphoma in mouse model, it rarely transforms primary human CD4+ T lymphocytes. In contrast, Tax-2 efficiently immortalizes human CD4+ T cells though it exhibits a lower transforming activity in rodent cells as compared to Tax-1. We here discuss our recent observation and views on the differential transforming activity of Tax-1 and Tax-2 in human T cells. PMID:24065965

Ren, Tong; Cheng, Hua

2013-09-23

347

Use of HLA-DR*08032/E7 and HLA-DR*0818/E7 tetramers in tracking of epitope-specific CD4+ T cells in active and convalescent tuberculosis patients compared with control donors.  

PubMed

Comparative tracking of tetramer-positive and epitope-specific CD4(+) T cells in blood and other tissues from tuberculosis (TB) patients during TB development and treatment using control donor samples is not well characterized. In this study, a novel HLA-DR-restricted peptide E7 from the ESAT-6 protein of Mycobacterium tuberculosis (MTB) was used to prepare modified HLA-DR*08032/E7 tetramer (tetramer 1) and HLA-DR*0818/E7 tetramer (tetramer 2) to monitor a series of samples from TB patients and control donors. Tetramer staining showed that (1) by direct staining of single sample and flow cytometric analyses, detection of tetramer-positive CD4(+) T cells ranged from 0.1% to 8.8% (median 0.67% in tetramer 1 and 0.5% in tetramer 2), 0.1 to 10.7% (0.74% and 0.71%), 0.02 to 2.2% (0.25% and 0.25%), 0.02 to 0.48% (0.2% and 0.2%) and most at under 0-0.2% (0.2% and 0.16%) in the initial pulmonary TB (PTB) patients' blood, pleural fluid (PLF) of initial tuberculous pleuritis patients, non-TB patients' blood, healthy donors' blood and umbilical cord blood, respectively; significantly higher levels of CD4(+) T cells were detected in samples of TB patients than in three control donor groups; (2) by direct staining of time point TB samples and flow cytometric analyses, along with TB symptom amendment at day 60, tetramer-positive CD4(+) T cells began to decrease, until after 90-120 days, reached and kept at a relatively low even normal level about at 0.03-0.3%; (3) by enrichment approach, at least 10-fold increased memory tetramer-positive CD4(+) T cells were seen; (4) by in situ staining, tetramer-positive, IFN-?-producing and/or TNF-?-producing CD4(+) T cells in the lymph node and lung granuloma and cavernous tissues of TB patients could be determined. Therefore, by further increasing the sample size tested to confirm the specificity and sensitivity of tetrameric molecules, it should be possible to develop them for use as research and diagnostic reagents. PMID:21281984

Li, Yan; Zhu, Yan; Zhou, Lin; Fang, Yimin; Huang, Lirong; Ren, Liangliang; Peng, Yi; Li, Yifen; Yang, Fangfang; Xie, Dan; Tang, Wenzheng; Zhang, Na; Zhong, Qiu; Lai, Xiaomin

2011-01-12

348

Immortalization and altered differentiation of human keratinocytes in vitro by the E6 and E7 open reading frames of human papillomavirus type 18.  

PubMed Central

The E6-E7 region of human papillomavirus types 16 and 18 is selectively retained and expressed in cervical carcinoma cells. In cultured human keratinocytes, expression of the E6 and E7 open reading frames of human papillomavirus type 18, under the control of its homologous promoter, resulted in high-frequency immortalization. Furthermore, by using a system that allows for stratification of keratinocytes in vitro (raft system), we observed that the morphological differentiation of these E6-E7 immortalized cells was altered such that parabasal cells extended throughout most of the epithelium, with abnormal nuclei present in the upper regions. Examination of E6-E7-expressing cell lines in the raft system at a later passage revealed that complete loss of morphological differentiation had occurred. E7 alone was a much less effective immortalizing agent than E6 and E7 together and acted only minimally to alter morphological differentiation in vitro. No such activities were found for E6 alone. High-frequency transformation of human epithelial cells thus appears to require expression of both E6 and E7 gene products. Images

Hudson, J B; Bedell, M A; McCance, D J; Laiminis, L A

1990-01-01

349

Different domains of glycoprotein 96 influence HPV16 E7 DNA vaccine potency via electroporation mediated delivery in tumor mice model.  

PubMed

DNA vaccines have emerged as a promising approach for generating antigen-specific immunotherapy. However, due to their low immunogenicity, there is a need to enhance DNA-based vaccine potency. Two main strategies to increase DNA-based vaccine potency are the employment of immuno-adjuvants such as heat shock proteins (HSPs) and a method of improving the delivery of naked plasmid DNA by electroporation. In the current study, we evaluated the effects of linkage of human papillomavirus (HPV) type 16 E7 as a model antigen to N-terminal and C-terminal of glycoprotein 96 (NT-/CT-gp96) on the potency of E7-specific immunity generated by DNA vaccines. We found that subcutaneous DNA injection with E7-CT (gp96) followed by electroporation generates the significant E7-specific IFN-? immune responses as well as the best protective effects in vaccinated mice as compared to E7 or E7-NT (gp96) DNA vaccines. Therefore, our data indicate that subcutaneous administration of E7 DNA linked to CT (gp96) fragment followed by electroporation can significantly enhance the potency of DNA vaccines. Indeed, the structural domains of immuno-chaperones show the potential of generating effective immune responses against different clinical disorders such as cancer. Altogether, our results show that comparable regions of gp96 (N-/C-terminal fragments of gp96) may have qualitatively different immunological effects in vaccine design. PMID:23085605

Daemi, Amin; Bolhassani, Azam; Rafati, Sima; Zahedifard, Farnaz; Hosseinzadeh, Sahar; Doustdari, Fatemeh

2012-10-17

350

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

351

Direct effects of Bmi1 on p53 protein stability inactivates oncoprotein stress responses in embryonal cancer precursor cells at tumor initiation.  

PubMed

Embryonal cancer can arise from postnatally persistent embryonal remnant or rest cells, which are uniquely characterized by the absence of p53 mutations. Perinatal overexpression of the MycN oncoprotein in embryonal cancer precursor cells causes postnatal rests, and later tumor formation through unknown mechanisms. However, overexpression of Myc in adult tissues normally activates apoptosis and/or senescence signals as an organismal defense mechanism against cancer. Here, we show that perinatal neuroblastoma precursor cells exhibited a transiently diminished p53 response to MycN oncoprotein stress and resistance to trophic factor withdrawal, compared with their adult counterpart cells from the TH-MYCN(+/+) transgenic mouse model of neuroblastoma. The adult stem cell maintenance factor and Polycomb group protein, Bmi1 (B-cell-specific Moloney murine leukemia virus integration site), had a critical role at neuroblastoma initiation in the model, by repressing p53 responses in precursor cells. We further show in neuroblastoma tumor cells that Bmi1 could directly bind p53 in a complex with other Polycomb complex proteins, Ring1A or Ring1B, leading to increased p53 ubiquitination and degradation. Repressed p53 signal responses were also seen in precursor cells for other embryonal cancer types, medulloblastoma and acute lymphoblastic leukemia. Collectively, these date indicate a general mechanism for p53 inactivation in some embryonal cell types and consequent susceptibility to MycN oncogenesis at the point of embryonal tumor initiation. PMID:22907436

Calao, M; Sekyere, E O; Cui, H J; Cheung, B B; Thomas, W D; Keating, J; Chen, J B; Raif, A; Jankowski, K; Davies, N P; Bekkum, M V; Chen, B; Tan, O; Ellis, T; Norris, M D; Haber, M; Kim, E S; Shohet, J M; Trahair, T N; Liu, T; Wainwright, B J; Ding, H F; Marshall, G M

2012-08-20

352

DNA-EIA to detect high and low risk HPV genotypes in cervical lesions with E6/E7 primer mediated multiplex PCR.  

PubMed Central

BACKGROUND: Oncogenicity of human papillomavirus (HPV) DNA in premalignant and malignant uterine cervical diseases is mainly induced by E6/E7 open reading frame (ORF). The presence of an oncogenic HPV DNA may be a diagnostic marker for the detection of cytologically negative smears. AIMS: To evaluate an original polymerase chain reaction enzyme immunoassay (PCR-EIA) for the detection and typing of oncogenic and non-oncogenic HPV types. METHODS: The test was an original multiplex labelled PCR-EIA for the detection and typing of oncogenic and non-oncogenic HPV using three consensus sequence primers within the oncogenic E6/E7 ORF. One primer was dinitrophenyl (DNP) labelled and the DNP labelled amplimers could be further hybridised with specific biotinylated oligoprobes mixed in only two cocktails: oncogenic (16, 18, 31, 33, 35, 52, and 58) and non-oncogenic (6 and 11) HPV types in only two wells; then biotinylated oligoprobes were deposited in streptavidin-coated microplates. The PCR-EIA was validated on HPV plasmids (types 6, 11, 16, 18, 31, 35, 52, and 58) and used to evaluate cervical scrapes from 181 patients (median age 32 years) at high risk for cervical cancer. RESULTS: HPV were detected in the cervical scrapes of 88 of 181 patients (48.6%); nine with non-oncogenic HPV (5.0%) and 79 with oncogenic HPV (43.6%) including 29 coinfections with oncogenic and non-oncogenic HPV. The number of oncogenic HPV infections increased with the presence of high grade lesions: 95.8% of the cervical scrapes from patients with high grade lesions contained oncogenic HPV compared with 32.1% of the specimens from patients without any lesions detectable by colposcopy and/or by cytological examination of the cervical smears. Moreover, 60% of cervical scrapes exhibiting low grade lesions contained oncogenic HPV. CONCLUSIONS: This test is simple, specific, sensitive, safe, fast, reproducible, and easy to use in routine practice. Thus, it is possible to detect simultaneously on a simple cervical scrape, two kinds of HPV--oncogenic and non-oncogenic--in just two microplate wells with non-isotopic oligoprobes.

Clavel, C; Rihet, S; Masure, M; Chypre, C; Boulanger, J C; Quereux, C; Birembaut, P

1998-01-01

353

Nucleolar and nuclear localization properties of a herpesvirus bZIP oncoprotein, MEQ.  

PubMed Central

Marek's disease virus (MDV) is one of the most oncogenic herpesviruses and induces T lymphomas in chickens within weeks after infection. Only a limited number of viral transcripts are detected in MDV tumor samples and cell lines. One of the major transcripts encodes MEQ, a 339-amino-acid bZIP protein which is homologous to the Jun/Fos family of transcription factors. The C-terminal half of MEQ contains proline-rich repeats and, when fused to the DNA-binding domain of a yeast transcription factor, Gal4 (residues 1 to 147), exhibits transactivation function. MEQ can dimerize with itself and with c-Jun. The MEQ-c-Jun heterodimers bind to an AP-1-like enhancer within the MEQ promoter region with greater affinity than do homodimers of either protein, and they transactivate MEQ expression. Here we show that MEQ is expressed in the nucleus but, interestingly, with a predominant fraction in the nucleoli and coiled bodies. This makes MEQ the first bZIP protein to be identified in the nucleoli. MEQ contains two stretches of basic residues, designated basic region 1 (BR1) and basic region 2 (BR2). Using a series of deletion mutants, we have mapped the primary nuclear localization signal (NLS) and the sole nucleolar localization signal (NoLS) to the BR2 region. BR1 was shown to provide an auxiliary signal in nuclear translocation. To demonstrate that BR2 is an authentic NoLS, BR2 was fused to cytoplasmic v-Raf (delta gag) kinase. The BR2-Raf fusion protein was observed to migrate into the nucleoplasm and the nucleolus. The BR2 region can be further divided into two long arginine-lysine stretches, BR2N and BR2C, which are separated by the five amino acids Asn-Arg-Asp-Ala-Ala (NRDAA). We provide evidence that the requirement for nuclear translocation is less stringent than that for nucleolar translocation, as either BR2N or BR2C alone is sufficient to translocate the cytoplasmic v-Raf (delta gag) into the nucleus, but only in combination can they translocate v-Raf (delta gag) into the nucleolus. Our studies demonstrate that MEQ is both a nuclear and nucleolar protein, adding MEQ to the growing list of transactivators which localize to the nucleolus.

Liu, J L; Lee, L F; Ye, Y; Qian, Z; Kung, H J

1997-01-01

354

Transcriptional upregulation of histone deacetylase 2 promotes Myc-induced oncogenic effects  

Microsoft Academic Search

Myc oncoproteins and histone deacetylases (HDACs) modulate gene transcription and enhance cancer cell proliferation, and HDAC inhibitors are among the most promising new classes of anticancer drugs. Here, we show that N-Myc and c-Myc upregulated HDAC2 gene expression in neuroblastoma and pancreatic cancer cells, respectively, which contributed to N-Myc- and c-Myc-induced cell proliferation. Cyclin G2 (CCNG2) was commonly repressed by

G M Marshall; S Gherardi; N Xu; Z Neiron; T Trahair; C J Scarlett; D K Chang; P Y Liu; K Jankowski; N Iraci; M Haber; M D Norris; J Keating; E Sekyere; G Jonquieres; F Stossi; B S Katzenellenbogen; A V Biankin; G Perini; T Liu

2010-01-01

355

Inhibition of E6-induced Degradation of its Cellular Substrates by Novel Blocking Peptides  

Microsoft Academic Search

The E6 oncoprotein derived from the tumour-associated human papillomavirus (HPV) types induces the ubiquitin-mediated degradation of several cellular proteins by conjugating them with the cellular ubiquitin ligase E6-AP. This is a HECT domain-containing ligase that was originally identified through its involvement in the E6-mediated degradation of the cellular tumour suppressor protein p53. Here we have investigated, in more detail, the

Helena Sterlinko Grm; Malte Weber; Rob Elston; Pauline McIntosh; Heather Griffin; Lawrence Banks; John Doorbar

2004-01-01

356

International Conference on Harmonisation; Guidance on E7 Studies in Support of Special Populations; Geriatrics; Questions and Answers; availability. Notice.  

PubMed

The Food and Drug Administration (FDA) is announcing the availability of a guidance entitled ``E7 Studies in Support of Special Populations: Geriatrics; Questions and Answers.'' The guidance was prepared under the auspices of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH). The questions and answers (Q&A) guidance addresses special considerations for the design and conduct of clinical trials of drugs likely to have significant use in the elderly. The Q&As are intended to provide guidance on the use of geriatric data to adequately characterize and represent the safety and efficacy of a drug for a marketing application, including data collected postmarketing. PMID:22379685

2012-02-21

357

From the Cover: MUC1-induced alterations in a lipid metabolic gene network predict response of human breast cancers to tamoxifen treatment  

Microsoft Academic Search

The mucin 1 (MUC1) oncoprotein is aberrantly overexpressed in human breast cancers. Although MUC1 modulates the activity of estrogen receptor alpha (ER), there is no information regarding the effects of MUC1 on global gene expression patterns and the potential role of MUC1-induced genes in predicting outcome for breast cancer patients. We have developed an experimental model of MUC1-induced transformation that

Sean P. Pitroda; Nikolai N. Khodarev; Michael A. Beckett; Donald W. Kufe; Ralph R. Weichselbaum

2009-01-01

358

Epidermal cancer associated with expression of human papillomavirus type 16 E6 and E7 oncogenes in the skin of transgenic mice.  

PubMed

Certain "high-risk" anogenital human papillomaviruses (HPVs) have been associated with the majority of human cervical carcinomas. In these cancers, two papillomaviral genes, E6 and E7, are commonly expressed. In this study we provide evidence that expression of the E6 and E7 genes from the high-risk HPV-16 in the skin of transgenic mice potentiated the development of preneoplastic lesions, and a high percentage of these epidermal lesions subsequently developed into locally invasive cancers. High levels of E6/E7 expression were found in these tumors relative to the preneoplastic lesions, and expression was localized to the proliferating, poorly differentiated epidermal cells. Also, the p53 and Rb genes were found to be intact, not mutationally inactivated, in representative skin tumors. These findings demonstrate that the E6 and E7 genes from a papillomavirus etiologically associated with human cervical cancer can contribute to the development of epidermal cancers in an animal model. PMID:8390671

Lambert, P F; Pan, H; Pitot, H C; Liem, A; Jackson, M; Griep, A E

1993-06-15

359

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

Microsoft Academic Search

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

M. Von Knebel Doeberitz; T. Bauknecht; D. Bartsch; H. Zur Hausen

1991-01-01

360

The pro-angiogenic factors stimulated by human papillomavirus type 16 E6 and E7 protein in C33A and human fibroblasts.  

PubMed

To investigate the pro-angiogenic factors stimulated by human papillomavirus type 16 E6 and E7 protein in C33A and human fibroblasts. HPV-16 E6 and E7 genes were transfected into C33A and HFB to detect the profiling of angiogenesis-associated factors with the TranSignal angiogenesis antibody array. The mRNA and protein levels of the cytokines were examined by traditional RT-PCR and Western blotting in both cell lines before and after transfection of HPV-16 E6 and E7. HPV-16 E6 and E7 genes were successfully transfected into C33A and HFB cells. On the sheet of antibody array, after transfection of HPV-16 E6 and E7, 6 other cytokines, Ang-1, FGFalpha, HGF, IL-6, IP-10 and PIGF besides VEGF, were detected at higher levels in C33A cells. Expression of 7 other cytokines besides IL-8, Ang-1, IL-1alpha, IL-1beta, HGF, IL-6, VEGF and PIGF increased in HFB cells. The common cytokines in both cell lines were Ang-1, HGF, PIGF and VEGF. The mRNA and protein levels of the four cytokines were verified to increase by traditional RT-PCR and Western blotting in both cell lines after transfection of HPV-16 E6 and E7. Multiple pro-angiogenic cytokines could be stimulated by HPV-16 E6 and E7 protein both in cervical cancer cell line and normal human diploid cells. Anti-angiogenesis therapy may be effective alone or in combination with biologic means aimed at E6 and E7 in the treatment of cervical cancer. PMID:19082439

Xi, Ling; Wang, Shixuan; Wang, Changyu; Xu, Qian; Li, Pengcheng; Tian, Xun; Wu, Peng; Wang, Wei; Deng, Dongrui; Zhou, Jianfeng; Ma, Ding

2009-01-01

361

Genetic immunization against cervical carcinoma: induction of cytotoxic T lymphocyte activity with a recombinant alphavirus vector expressing human papillomavirus type 16 E6 and E7  

Microsoft Academic Search

Infection of genital epithelial cells with human papillomavirus (HPV) types 16 and 18 is closely associated with the development of cervical carcinoma. The transforming potential of these high-risk HPVs depends on the expression of the E6 and E7 early viral gene products. Since the expression of E6 and E7 is selectively maintained in premalignant and malignant cervical lesions these proteins

T Daemen; F Pries; L Bungener; M Kraak; J Regts; J Wilschut

2000-01-01

362

A recombinant vaccinia virus encoding human papillomavirus types 16 and 18, E6 and E7 proteins as immunotherapy for cervical cancer  

Microsoft Academic Search

SummaryBackground Human papillomavirus (HPV) infection, especially with type 16 or 18, is associated with cervical cancer. Two HPV proteins, E6 and E7, are consistently expressed in tumour cells. The objectives of the study were to examine the clinical and environmental safety and immunogenicity in the first clinical trial of a live recombinant vaccinia virus expressing the E6 and E7 proteins

L. K Borysiewicz; A Fiander; M Nimako; S Man; G. W. G Wilkinson; D Westmoreland; A. S Evans; M Adams; S. N Stacey; M. E. G Boursnell; E Rutherford; J. K Hickling; S. C Inglis

1996-01-01

363

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.

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

2012-01-01

364

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

365

Does the expression of HPV16/18 E6/E7 in head and neck squamous cell carcinomas relate to their clinicopathological characteristics?  

PubMed

Human papilloma virus (HPV) has been recently proposed to be implicated in the development of head and neck squamous cell carcinoma (HNSCC) in patients without cancer risk. We examined the expression of HPV16/18 E6/E7 in 71 cases of HNSCCs and investigated abnormalities of the p53 gene in 62 of these 71 cases. Expression of HPV16 E6/E7 was observed in 11 of the 71 cases (15.5%), while expression of HPV18 E6/E7 was not observed in any of the cases. Most of the HPV16 E6/E7-positive cases were histopathologically characterized by their verrucous or papillary structure and koilocytosis of the adjacent mucosa. There was no clear relationship between expression of HPV16 E6/E7 and tumor stage, prognosis or the positive rate of p53 abnormality. These results suggest that approximately 15% of HNSCCs are caused by HPV16 infection and the subsequent constitutive expression of E6 and E7, and that some HPV-initiated tumors lose their original characteristics during tumor progression. PMID:19787251

Yamakawa-Kakuta, Yoshiko; Kawamata, Hitoshi; Doi, Yutaka; Fujimori, Takahiro; Imai, Yutaka

2009-11-01

366

A non-pathogenic live vector as an efficient delivery system in vaccine design for the prevention of HPV16 E7-overexpressing cancers.  

PubMed

The attenuated or non-pathogenic live vectors have been evolved specifically to deliver DNA into cells as efficient delivery tools in gene therapy. Recently, a non-pathogenic protozoan, Leishmania tarentolae (L.tar) has attracted a great attention. In current study, we used Leishmania expression system (LEXSY) for stable expression of HPV16 E7 linked to different mini-chaperones [N-/C-terminal of gp96] and compared their immunogenicity and protective effects in C57BL/6 mice against TC-1 challenge. TC-1 murine model is primary C57BL/6 mice lung epithelial cells co-transformed with HPV16 E6, HPV16 E7 and ras oncogenes. Our results showed that subcutaneous administration of mice with both the recombinant L.tar-E7-NT (gp96) and L.tar-E7-CT (gp96) led to enhance the levels of IFN-? and also IgG2a before and after challenge with TC-1. Furthermore, L.tar-E7-CT (gp96) live vaccine indicated significant protective effects as compared to control groups as well as group vaccinated with L.tar-E7. Indeed, the recombinant live vector is capable of eliciting effective humoral and cellular immune responses in mice, but however, further studies are required to increase their efficacy. PMID:23745741

Hosseinzadeh, Sahar; Bolhassani, Azam; Rafati, Sima; Taheri, Tahereh; Zahedifard, Farnaz; Daemi, Amin; Taslimi, Yasaman; Hashemi, Mehrdad; Memarnejadian, Arash

367

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

368

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

369

Excision of Ets by an inducible site-specific recombinase causes differentiation of Myb–Ets-transformed hematopoietic progenitors  

Microsoft Academic Search

Background: The Myb–Ets protein encoded by the E26 acute avian leukemia virus is a paradigm for the function of fused transcriptional activator oncoproteins. Myb–Ets transforms hematopoietic progenitor cells (Myb–Ets progenitors, MEPs) that can be induced to differentiate into eosinophilic and myeloid cells by the activation of pathways involving Ras and\\/or protein kinase C. The Ets portion of the fusion protein

Fabio Rossi; Kelly M McNagny; Colin Logie; A. Francis Stewart; Thomas Graf

1996-01-01

370

p28GANK inhibits endoplasmic reticulum stress-induced cell death via enhancement of the endoplasmic reticulum adaptive capacity  

Microsoft Academic Search

It has been shown that oncoprotein p28GANK, which is consistently overexpressed in human hepatocellular carcinoma (HCC), plays a critical role in tumorigenesis of HCC. However, the underlying mechanism remains unclear. Here, we demonstrated that p28GANK inhibits apoptosis in HCC cells induced by the endoplasmic reticulum (ER) stress. During ER stress, p28GANK enhances the unfolded protein response, promotes ER recovery from

Rong-Yang Dai; Yao Chen; Jing Fu; Li-Wei Dong; Yi-Bin Ren; Guang-Zhen Yang; You-Wen Qian; Jie Cao; Shan-Hua Tang; Sheng-Li Yang; Hong-Yang Wang

2009-01-01

371

A novel self-assembled nanoparticle vaccine with HIV-1 Tat?????/HPV16 E7????? fusion peptide and GM-CSF DNA elicits potent and prolonged CD8? T cell-dependent anti-tumor immunity in mice.  

PubMed

Peptide-based vaccines derived from the E7 protein of human papillomavirus (HPV) type 16 were developed to induce effective T cell responses against established cervical cancer, but have met with limited clinical success. It is necessary to develop novel peptide-based strategies to substantially improve the immune response against HPV16-related cancer. In this study, we aimed to design a novel peptide-based self-assembled nanoparticle HPV16 vaccine by combining the cell-penetrating peptide HIV-1 Tat(49-57) that was fused with the HPV16 E7(49-57) cytotoxic T lymphocyte (CTL) epitope and the granulocyte-macrophage colony stimulating factor (GM-CSF) gene, and to investigate how it improves the immune response and the therapeutic outcome ex vivo and in vivo. Nanoparticles were prepared and identified by transmission electron microscopy (TEM), gel retardation and DNase I protection assays. This type of vaccine formulation formed the 20-80 nm nanoparticles, and greatly improved epitope-specific immunity both ex vivo and in vivo. Importantly, this vaccine type was associated with decreased tumor growth and enhanced long-term survival in the prophylactic and therapeutic mouse models. The underlying mechanisms were determined to involve priming of enhanced frequency of CD8(+) memory T subtype cells. These results suggest that the nanoparticle Tat-E7/pGM-CSF represents a promising novel approach to enhance the potency of peptide-based cervical cancer vaccines, and this vaccine design strategy may act as a useful reference for research of virus-associated diseases and specific tumor immunotherapies. PMID:22178528

Tang, Jun; Yin, Rui; Tian, Yi; Huang, Zeming; Shi, Jinglei; Fu, Xiaolan; Wang, Li; Wu, Yuzhang; Hao, Fei; Ni, Bing

2011-12-15

372

Rat primary embryo fibroblast cells suppress transformation by the E6 and E7 genes of human papillomavirus type 16 in somatic hybrid cells.  

PubMed Central

The E6 and E7 genes of human papillomavirus type 16 (HPV-16) transform established lines of rat cells but not rat cells in primary culture irrespective of the expression of the two genes. The reason for this difference between the susceptibilities of cell lines and primary cells was examined by using hybrid cells obtained by somatic cell fusion of rat cell lines transformed by the E6 and E7 genes of HPV-16 and freshly isolated rat embryo fibroblast cells. In these hybrid cells, transformed phenotypes, including colony formation in soft agar, saturation density, and tumorigenicity in nude mice, were suppressed, whereas hybrid cells between E6/E7-transformed cell lines and normal rat cell lines retained these transformed phenotypes. RNA analysis showed that the E6 and E7 genes were transcribed in both types of hybrid cells. These results suggest that primary rat cells possess intracellular functions that cause posttranscriptional suppression of induction of the transformed phenotypes by the E6 and E7 genes of HPV-16. Images

Miyasaka, M; Takami, Y; Inoue, H; Hakura, A

1991-01-01

373

Rearrangement of the distal pocket accompanying E7 His yields Gln substitution in elephant carbonmonoxy- and oxymyoglobin: sup 1 H NMR identification of a new aromatic residue in the heme pocket  

SciTech Connect

Two-dimensional {sup 1}H NMR methods have been used to assign side-chain resonances for the residues in the distal heme pocket of elephant carbonmonoxymyoglobin (MbCO) and oxymyoglobin (MbO{sub 2}). It is shown that, while the other residues in the heme pocket are minimally perturbed, the Phe CD4 residue in elephant MbCO and MbO{sub 2} resonates considerably upfield compared to the corresponding residue in sperm whale MbCO. The new NOE connectivities to Val E11 and heme-induced ring current calculations indicate that Phe CD4 has been inserted into the distal heme pocket by reorienting the aromatic side chain and moving the CD corner closer to the heme. The C{zeta}H proton of the Phe CD4 was found to move toward the iron of the heme by {approximately}4 {angstrom} relative to the position in sperm whale MbCO, requiring minimally a 3-{angstrom} movement of the CD helical backbone. The significantly altered distal conformation in elephant myoglobin, rather than the single distal E7 substitution, forms a plausible basis for its altered functional properties of lower autoxidation rate, higher redox potential, and increased affinity for CO ligand. These results demonstrate that one-to-one interpretation of amino acid residue substitution (E7 His {yields} Gln) is oversimplified and that conformational changes of substituted proteins which are not readily predicted have to be considered for interpretation of their functional properties.

Yu, L.P.; La Mar, G.N. (Univ. of California, Davis (USA)); Mizukami, H. (Wayne State Univ., Detroit, MI (USA))

1990-03-13

374

Oncoprotein HCCR-1 expression in breast cancer is well correlated with known breast cancer prognostic factors including the HER2 overexpression, p53 mutation, and ER\\/PR status  

Microsoft Academic Search

BACKGROUND: Oncoprotein HCCR-1 functions as a negative regulator of the p53 and contributes breast tumorigenesis. The serum HCCR-1 assay is useful in diagnosing breast cancer and mice transgenic for HCCR developed breast cancers. But it is unknown how HCCR-1 contributes to human breast tumorigenesis. METHODS: Oncogene HCCR-1 expression levels were determined in normal breast tissues, breast cancer tissues and cancer

Seon-Ah Ha; Youn Soo Lee; Seung Min Shin; Hyun Kee Kim; Sanghee Kim; Hong Namkoong; Hae Joo Kim; Sang Min Jung; Yu Sun Lee; Yeun Jun Chung; Sang Seol Jung; Jin Woo Kim

2009-01-01

375

Exogenous cdk4 overcomes reducedcdk4 RNA and inhibition of G1 progression in hematopoietic cells expressing a dominant-negative CBF – a model for overcoming inhibition of proliferation by CBF oncoproteins  

Microsoft Academic Search

Core Binding Factor (CBF) is required for the development of definitive hematopoiesis, and the CBF oncoproteins AML1-ETO, TEL-AML1, and CBF?-SMMHC are commonly expressed in subsets of acute leukemia. CBF?-SMMHC slows the G1 to S cell cycle transition in hematopoietic cells, but the mechanism of this effect is uncertain. We have sought to determine whether inhibition of CBF-mediated trans-activation is sufficient

Jianrong Lou; Wangsen Cao; Florence Bernardin; Kasirajan Ayyanathan; Frank J Rauscher; Alan D Friedman

2000-01-01

376

The Cytoplasmic Domain of MUC1 Induces Hyperplasia in the Mammary Gland and Correlates with Nuclear Accumulation of beta-Catenin  

Microsoft Academic Search

MUC1 is an oncoprotein that is overexpressed in up to 90% of breast carcinomas. A previous in vitro study by our group demonstrated that the cytoplasmic domain of MUC1 (MUC1-CD), the minimal functional unit of MUC1, contributes to the malignant phenotype in cells by binding directly to ?-catenin and protecting ?-catenin from GSK3?-induced degradation. To understand the in vivo role

Yuan Li; Haiying Yi; Yixin Yao; Xiaodong Liao; Yiqun Xie; Jie Yang; Zheng Yan; Long Wang; Shunyuan Lu; Ying Kuang; Mingmin Gu; Jian Fei; Zhugang Wang; Lei Huang; Cara Gottardi

2011-01-01

377

A combined assay of hTERT and E6 oncoprotein to identify virus-infected keratinocytes with higher telomerase activity in human papillomaviruses 16 and 18-related bowenoid papulosis.  

PubMed

In the present study, we aim to evaluate the application potential of a combined assay of human telomerase reverse transcriptase (hTERT) and E6 oncoprotein in screening the virus-infected keratinocytes with higher telomerase activity in human papillomaviruses (HPV) 16- and 18-related bowenoid papulosis (BP). HPV16/18 DNA in BP (n = 123) was identified by in situ hybridization, the expression of hTERT and E6 in HPV16/18-related BP (n = 68) was determined by immunohistochemistry. We demonstrated that the expression of hTERT correlated well with that of E6 oncoprotein in HPV16/18-related BP lesions (Spearman rho = 0.868, P < 0.01). Furthermore, the majority of keratinocytes with positive nuclear staining for hTERT or E6 in the consecutive sections of each HPV16/18-related BP lesion showed nuclear paleomorphism or nuclear mitosis. In conclusion, we suggested that a combined assay of hTERT and E6 oncoprotein can be used to screen the HPV-infected keratinocytes with higher telomerase activity in HPV16-related and HPV18-related BP lesions. PMID:22688392

Li, Dongsheng; Dong, Bilin; Hu, Zhimin; Chen, Liuqing; Zeng, Xianyu; Chen, Jinbo; Duan, Yiqun

2012-12-01

378

Virus-Like Particles Harboring CCL19, IL-2 and HPV16 E7 Elicit Protective T Cell Responses in HLA-A2 Transgenic Mice.  

PubMed

Infection by high-risk genotypes of human papillomaviruses (HR-HPVs) is the cause of cancer of the uterine cervix. Although prophylactic vaccines directed against the two most prevalent HR-HPV types (HPV16 and 18) have been commercialized recently, there is a need for effective therapeutic vaccines against HR-HPVs. We have tested in mice a chimeric protein composed of the hepatitis B small surface antigen (HBsAg(S)) flanked at its N-terminus by chemokine CC ligand 19/macrophage inflammatory protein-3? (CCL19/MIP-3?), and at the C-terminus by interleukin 2 (IL-2) and an artificial HPV16 E7 polytope. This protein is assembled into nanoparticles and both CCL19 and IL-2 conserve their functionality. HLA-A2 (AAD) transgenic mice immunized with a plasmid encoding this protein mounted specific T cell responses against E7 without the need of an adjuvant. Furthermore, vaccination prevented the development of tumors after implantation of the E6/E7-expressing TC-1/A2 tumor cell line. Our results suggest that vaccines based on HBsAg(S) nanoparticles carrying short E7 epitopes and immune-stimulatory domains might be of therapeutic value in the treatment of patients suffering from cervical pre-cancer or cancer lesions caused by HR-HPVs. PMID:23341863

Juarez, Victoria; Pasolli, H Amalia; Hellwig, Andrea; Garbi, Natalio; Arregui, Angel Cid

2012-12-28

379

Virus-Like Particles Harboring CCL19, IL-2 and HPV16 E7 Elicit Protective T Cell Responses in HLA-A2 Transgenic Mice  

PubMed Central

Infection by high-risk genotypes of human papillomaviruses (HR-HPVs) is the cause of cancer of the uterine cervix. Although prophylactic vaccines directed against the two most prevalent HR-HPV types (HPV16 and 18) have been commercialized recently, there is a need for effective therapeutic vaccines against HR-HPVs. We have tested in mice a chimeric protein composed of the hepatitis B small surface antigen (HBsAg(S)) flanked at its N-terminus by chemokine CC ligand 19/macrophage inflammatory protein-3? (CCL19/MIP-3?), and at the C-terminus by interleukin 2 (IL-2) and an artificial HPV16 E7 polytope. This protein is assembled into nanoparticles and both CCL19 and IL-2 conserve their functionality. HLA-A2 (AAD) transgenic mice immunized with a plasmid encoding this protein mounted specific T cell responses against E7 without the need of an adjuvant. Furthermore, vaccination prevented the development of tumors after implantation of the E6/E7-expressing TC-1/A2 tumor cell line. Our results suggest that vaccines based on HBsAg(S) nanoparticles carrying short E7 epitopes and immune-stimulatory domains might be of therapeutic value in the treatment of patients suffering from cervical pre-cancer or cancer lesions caused by HR-HPVs.

Juarez, Victoria; Pasolli, H Amalia; Hellwig, Andrea; Garbi, Natalio; Arregui, Angel Cid

2012-01-01

380

Adenovirus-mediated transfer of human papillomavirus 16 E6\\/E7 antisense RNA and induction of apoptosis in cervical cancer  

Microsoft Academic Search

ObjectiveIn most cervical cancers, human papillomaviruses (HPVs) are identified. The E6 and E7 genes of HPVs encode proteins, that interfere with the function of the tumor suppressor proteins p53 and Rb. We are exploring the potential use of antisense HPV RNA transcripts for gene therapy for HPV-positive cervical cancers.

Katsuyuki Hamada; Toshiro Shirakawa; Akinobu Gotoh; Jack A. Roth; Michele Follen

2006-01-01