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1

The human papillomavirus E7 oncoprotein  

SciTech Connect

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

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

2009-02-20

2

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

PubMed

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

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

2014-01-01

3

E7 Oncoprotein of Novel Human Papillomavirus Type 108 Lacking the E6 Gene Induces Dysplasia in Organotypic Keratinocyte Cultures ?  

PubMed Central

The genome organization of the novel human papillomavirus type 108 (HPV108), isolated from a low-grade cervical lesion, deviates from those of other HPVs in lacking an E6 gene. The three related HPV types HPV103, HPV108, and HPV101 were isolated from cervicovaginal cells taken from normal genital mucosa (HPV103) and low-grade (HPV108) and high-grade cervical (HPV101) intraepithelial neoplasia (Z. Chen, M. Schiffman, R. Herrero, R. DeSalle, and R. D. Burk, Virology 360:447-453, 2007, and this report). Their unusual genome organization, against the background of considerable phylogenetic distance from the other HPV types usually associated with lesions of the genital tract, prompted us to investigate whether HPV108 E7 per se is sufficient to induce the above-mentioned clinical lesions. Expression of HPV108 E7 in organotypic keratinocyte cultures increases proliferation and apoptosis, focal nuclear polymorphism, and polychromasia. This is associated with irregular intra- and extracellular lipid accumulation and loss of the epithelial barrier. These alterations are linked to HPV108 E7 binding to pRb and inducing its decrease, an increase in PCNA expression, and BrdU incorporation, as well as increased p53 and p21CIP1 protein levels. A delay in keratin K10 expression, increased expression of keratins K14 and K16, and loss of the corneal proteins involucrin and loricrin have also been noted. These modifications are suggestive of infection by a high-risk papillomavirus. PMID:19153227

Nobre, Rui Jorge; Herráez-Hernández, Elsa; Fei, Jian-Wei; Langbein, Lutz; Kaden, Sylvia; Gröne, Hermann-Josef; de Villiers, Ethel-Michele

2009-01-01

4

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

PubMed Central

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

2013-01-01

5

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

2012-02-01

6

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

7

The E7 oncoprotein associates with Mi2 and histone deacetylase activity to promote cell growth.  

PubMed Central

E7 is the main transforming protein of human papilloma virus type 16 (HPV16) which is implicated in the formation of cervical cancer. The transforming activity of E7 has been attributed to its interaction with the retinoblastoma (Rb) tumour suppressor. However, Rb binding is not sufficient for transformation by E7. Mutations within a zinc finger domain, which is dispensable for Rb binding, also abolish E7 transformation functions. Here we show that HPV16 E7 associates with histone deacetylase in vitro and in vivo, via its zinc finger domain. Using a genetic screen, we identify Mi2beta, a component of the recently identified NURD histone deacetylase complex, as a protein that binds directly to the E7 zinc finger. A zinc finger point mutant which is unable to bind Mi2beta and histone deacetylase but is still able to bind Rb fails to overcome cell cycle arrest in osteosarcoma cells. Our results suggest that the binding to a histone deacetylase complex is an important parameter for the growthpromoting activity of the human papilloma virus E7 protein. This provides the first indication that viral oncoproteins control cell proliferation by targeting deacetylation pathways. PMID:10228159

Brehm, A; Nielsen, S J; Miska, E A; McCance, D J; Reid, J L; Bannister, A J; Kouzarides, T

1999-01-01

8

Expression of the high-risk human papillomavirus type 18 and 45 E7 oncoproteins in cervical carcinoma biopsies.  

PubMed

E7 proteins are major oncoproteins of high-risk human papillomaviruses (HPVs), which play a key role in cervical carcinogenesis. These proteins have been shown to immortalize primary human cells. Due to the absence of antibodies with suitable sensitivity and specificity, little is known about expression of the E7 oncoproteins in naturally infected tissues. Recently, high-level expression of the E7 protein of HPV-16, the most prevalent oncogenic HPV type, was demonstrated in cervical carcinomas by immunohistochemistry; however, approximately 15 additional high-risk HPV types are known to be associated with cervical carcinoma. It is unknown whether the E7 oncoproteins of HPV-18 and -45, the second and third most prevalent HPV types, are expressed in cervical cancers. Using antibodies against HPV-18 and -45 E7 proteins, it is shown here for the first time that the HPV-18 and -45 E7 proteins can be detected in cervical carcinoma biopsies. Together with anti-HPV-16 E7 antibodies, this could create the possibility of detecting E7 oncoproteins in approximately 80 % of all cervical cancers. PMID:16298968

Fiedler, Marc; Ressler, Sigrun; Campo-Fernández, Beatriz; Laich, Andreas; Jansen, Lars; Widschwendter, Andreas; Viertler, Hans-Peter; Bacher, Nicole; Morandell, Dieter; Müller-Holzner, Elisabeth; Dürst, Matthias; Jansen-Dürr, Pidder; Zwerschke, Werner

2005-12-01

9

Purification and characterisation of the E7 oncoproteins of the high-risk human papillomavirus types 16 and 18.  

PubMed

E7 proteins are major oncoproteins of human papillomaviruses (HPVs) which play a key role in virus-associated cervical carcinogenesis. The E7 oncoprotein of HPV-16 has been shown to interact with a variety of cellular target proteins and these interactions are considered essential for the transforming properties of this oncoprotein. Several additional HPV types associated etiologically to cervical cancer have been described, the second most common being HPV-18. Less is known about the biochemical functions and interactions of HPV-18 E7. As a first step to determine biochemical properties common to the E7 proteins of the high-risk HPV types 16 and 18 these E7 proteins were expressed in bacteria and purified to homogeneity. Purified E7 proteins were used to investigate the in vitro interaction with the pocket protein p107 and insulin-like growth factor-binding protein-3 (IGFBP-3) that are known to interact with the amino-terminal and the carboxyl-terminal part of IGFBP-3, respectively. Both purified E7 proteins interacted strongly with p107 and, as demonstrated here for the first time, HPV-18 E7 was capable of binding to IGFBP-3, albeit to a lesser extent than HPV-16 E7. These findings suggest that the purified recombinant E7 proteins retain, at least in part, their biochemical activities. PMID:16384614

Fiedler, Marc; Campo-Fernández, Beatriz; Laich, Andreas; Moser, Barbara; Stöckl, Petra; Jansen-Dürr, Pidder; Zwerschke, Werner

2006-06-01

10

Dendritic cell-based tumor vaccine for cervical cancer I: in vitro stimulation with recombinant protein-pulsed dendritic cells induces specific T cells to HPV16 E7 or HPV18 E7  

Microsoft Academic Search

PurposeHuman papillomavirus (HPV) type 16 and 18 are the most prevalent genotypes in cervical cancers. The viral oncoproteins E6 and E7 are considered to be tumor-specific targets for immunotherapy. HPV E7 antigen-loaded dendritic cells (DC) were evaluated as cellular tumor vaccine.MethodsAutologous monocyte-derived DCs loaded with recombinant HPV16 or HPV18 E7 oncoprotein were used to induce in vitro a specific T

Marion Nonn; Manuela Schinz; Klaus Zumbach; Michael Pawlita; Achim Schneider; Matthias Dürst; Andreas M. Kaufmann

2003-01-01

11

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

PubMed

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

Yu, Yueyang; Munger, Karl

2012-10-10

12

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

SciTech Connect

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 [Division of Infectious Diseases, Brigham and Women's Hospital and Biological and Biomedical Sciences Program, Harvard Medical School, Boston, MA 02115 (United States)] [Division of Infectious Diseases, Brigham and Women's Hospital and Biological and Biomedical Sciences Program, Harvard Medical School, Boston, MA 02115 (United States); Munger, Karl, E-mail: kmunger@rics.bwh.harvard.edu [Division of Infectious Diseases, Brigham and Women's Hospital and Biological and Biomedical Sciences Program, Harvard Medical School, Boston, MA 02115 (United States)] [Division of Infectious Diseases, Brigham and Women's Hospital and Biological and Biomedical Sciences Program, Harvard Medical School, Boston, MA 02115 (United States)

2012-10-10

13

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. PMID:22748180

Yu, Yueyang; Munger, Karl

2012-01-01

14

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

2011-01-01

15

Molecular interactions of 'high risk' human papillomaviruses E6 and E7 oncoproteins: implications for tumour progression.  

PubMed

The aetiology of cervical cancer has been primarily attributed to human papillomaviruses (HPVs). These are characterized by the persistent expression of the two oncogenes, E6 and E7. Experimental studies show that E6 and E7 genes of the high risk HPVs deregulate key cell cycle controls. Recent work has uncovered new cellular partners for these proteins that throw light on many of the pathways and processes in which these viral proteins intervene. This review focuses on the regulation of host proteins by the viral oncoproteins and consequence of such interactions on cell survival, proliferation, differentiation and apoptosis. PMID:12734411

Chakrabarti, Oishee; Krishna, Sudhir

2003-04-01

16

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

PubMed Central

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

Dichamp, Isabelle; Seite, Paule; Agius, Gerard; Barbarin, Alice; Beby-Defaux, Agnes

2014-01-01

17

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

PubMed

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

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

2014-01-01

18

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. PMID:10906182

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

2000-01-01

19

Human Papillomavirus E7 Oncoprotein Increases Production of the Anti-Inflammatory Interleukin-18 Binding Protein in Keratinocytes  

PubMed Central

ABSTRACT Human papillomavirus (HPV) can successfully evade the host immune response to establish a persistent infection. We show here that expression of the E7 oncoprotein in primary human keratinocytes results in increased production of interleukin-18 (IL-18) binding protein (IL-18BP). This anti-inflammatory cytokine binding protein is a natural antagonist of IL-18 and is necessary for skin homeostasis. We map increased IL-18BP production to the CR3 region of E7 and demonstrate that this ability is shared among E7 proteins from different HPV types. Furthermore, mutagenesis shows that increased IL-18BP production is mediated by a gamma-activated sequence (GAS) in the IL-18BP promoter. Importantly, the increased IL-18BP levels seen in E7-expressing keratinocytes are capable of diminishing IL-18-mediated CD4 lymphocyte activation. This study provides the first evidence for a virus protein that targets IL-18BP and further validates E7 as a key component of the HPV immune evasion armor. IMPORTANCE Infection with human papillomavirus is a leading cause of morbidity and mortality worldwide. This study demonstrates that the E7 protein increases production of the anti-inflammatory IL-18BP, a major regulator of epithelial homeostasis. A number of E7 proteins can increase IL-18BP production, and a region within the CR3 of E7 is necessary for mediating the increase. A consequence of increased IL-18BP production is a reduction in CD4-positive lymphocyte activation in response to IL-18 costimulation. These findings may shed light on the immune evasion abilities of HPV. PMID:24478434

Richards, Kathryn H.; Doble, Rosella; Wasson, Christopher W.; Haider, Mohammed; Blair, G. Eric; Wittmann, Miriam

2014-01-01

20

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. PMID:21738683

Laurson, Joanna; Raj, Kenneth

2011-01-01

21

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

2012-01-20

22

Human Papillomavirus Type 16 E7 oncoprotein inhibits the anaphase promoting complex/cyclosome activity by dysregulating EMI1 expression in mitosis  

PubMed Central

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

2013-01-01

23

Identification of the FHL2 transcriptional coactivator as a new functional target of the E7 oncoprotein of human papillomavirus type 16.  

PubMed

We identified the transcriptional coactivator FHL2 as a novel target of the human papillomavirus type 16 (HPV-16) E7 oncoprotein, which plays a major role in cell transformation. The interaction with FHL2 is abolished by mutations in conserved regions 1 and 2 and in the C-terminal zinc finger domain of E7, all required for its transforming potential. We found that E7 impairs the coactivator function of FHL2 on both beta-catenin/LCF-dependent and AP-1-dependent promoters. Thus, the interaction with HPV-16 E7 leads to a promoter-specific impairment of FHL2 function and this may contribute to cell transformation. PMID:17093190

Campo-Fernández, Beatriz; Morandell, Dieter; Santer, Frédéric R; Zwerschke, Werner; Jansen-Dürr, Pidder

2007-01-01

24

Nuclear import of cutaneous beta genus HPV8 E7 oncoprotein is mediated by hydrophobic interactions between its zinc-binding domain and FG nucleoporins.  

PubMed

We have previously discovered and characterized the nuclear import pathways for the E7 oncoproteins of mucosal alpha genus HPVs, type 16 and 11. Here we investigated the nuclear import of cutaneous beta genus HPV8 E7 protein using confocal microscopy after transfections of HeLa cells with EGFP-8E7 and mutant plasmids and nuclear import assays in digitonin-permeabilized HeLa cells. We determined that HPV8 E7 contains a nuclear localization signal (NLS) within its zinc-binding domain that mediates its nuclear import. Furthermore, we discovered that a mostly hydrophobic patch 65LRLFV69 within the zinc-binding domain is essential for the nuclear import and localization of HPV8 E7 via hydrophobic interactions with the FG nucleoporins Nup62 and Nup153. Substitution of the hydrophobic residues within the 65LRLFV69 patch to alanines, and not R66A mutation, disrupt the interactions between the 8E7 zinc-binding domain and Nup62 and Nup153 and consequently inhibit nuclear import of HPV8 E7. PMID:24418548

Onder, Zeynep; Moroianu, Junona

2014-01-20

25

The retinoblastoma protein-associated cell cycle arrest in S-phase under moderate hypoxia is disrupted in cells expressing HPV18 E7 oncoprotein.  

PubMed

We have studied the role of the oxygen-dependent pyrimidine metabolism in the regulation of cell cycle progression under moderate hypoxia in human cell lines containing functional (T-47D) or non-functional (NHIK 3025, SAOS-2) retinoblastoma gene product (pRB). Under aerobic conditions, pRB exerts its growth-regulatory effects during early G1 phase of the cell cycle, when all pRB present has been assumed to be in the underphosphorylated form and bound in the nucleus. We demonstrate that pRB is dephosphorylated and re-bound in the nucleus in approximately 90% of T-47D cells located in S and G2 phases under moderately hypoxic conditions. Under these conditions, no T-47D cells entered S-phase, and no progression through S-phase was observed. Progression of cells through G2 and mitosis seems independent of their functional pRB status. The p21WAF1/CIP1 protein level was significantly reduced by moderate hypoxia in p53-deficient T-47D cells, whereas p16(INK4a) was not expressed in these cells, suggesting that the hypoxia-induced cell cycle arrest is independent of these cyclin-dependent kinase inhibitors. The addition of pyrimidine deoxynucleosides did not release T-47D cells, containing mainly underphosphorylated pRB, from the cell cycle arrest induced by moderate hypoxia. However, NHIK 3025 cells, in which pRB is abrogated by expression of the HPV18 E7 oncoprotein, and SAOS-2 cells, which lack pRB expression, continued cell cycle progression under moderate hypoxia provided that excess pyrimidine deoxynucleosides were present. NHIK 3025 cells express high levels of p16INK4a under both aerobic and moderately hypoxic conditions, suggesting that the inhibitory function of p16(INK4a) would not be manifested in such pRB-deficient cells. Thus, pRB, a key member of the cell cycle checkpoint network, seems to play a major role by inducing growth arrest under moderate hypoxia, and it gradually overrides hypoxia-induced suppression of pyrimidine metabolism in the regulation of progression through S-phase under such conditions. PMID:9528826

Amellem, O; Sandvik, J A; Stokke, T; Pettersen, E O

1998-03-01

26

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

SciTech Connect

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

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

2010-02-05

27

High level HPV-16 E7 oncoprotein expression correlates with reduced pRb-levels in cervical biopsies.  

PubMed

High-risk human papillomaviruses (HPVs) are major etiological agents of cervical cancer. Despite excellent epidemiological evidence for a direct role of HPV-16 in cervical carcinogenesis, molecular pathways underlying carcinogenesis in vivo remain obscure. The E7 gene is required for immortalization and maintenance of the transformed phenotype in vitro; however, little is known about its role for tumorigenesis in vivo. The E7 gene codes for an unstable protein the abundance of which in cervical biopsies is unknown. We show here that E7 protein levels strongly increase during cervical carcinogenesis, underlining its fundamental role in cervical cancer. The E7 protein was found predominantly in the nucleus and to a minor extent in the cytoplasm in the cervical cancer cell line Ca Ski in vitro and in invasive cervical carcinoma in situ, suggesting that nuclear resident E7 plays a major role in cervical carcinogenesis in humans. The retinoblastoma protein (pRb) is a major E7-target in vitro. We show here that pRb expression is initially upregulated in LSIL and disappears in later stages concomitant with increased E7 levels, suggesting that E7-driven degradation of pRb is involved in cervical tumorigenesis in humans. PMID:15155561

Fiedler, Marc; Müller-Holzner, Elisabeth; Viertler, Hans-Peter; Widschwendter, Andreas; Laich, Andreas; Pfister, Gerald; Spoden, Gilles A; Jansen-Dürr, Pidder; Zwerschke, Werner

2004-07-01

28

Molecular interactions of ‘high risk’ human papillomaviruses E6 and E7 oncoproteins: implications for tumour progression  

Microsoft Academic Search

The aetiology of cervical cancer has been primarily attributed to human papillomaviruses (HPVs). These are characterized by\\u000a the persistent expression of the two oncogenes, E6 and E7. Experimental studies show thatE6 andE7 genes of the high risk HPVs deregulate key cell cycle controls. Recent work has uncovered new cellular partners for these\\u000a proteins that throw light on many of the

Oishee Chakrabarti; Sudhir Krishna

2003-01-01

29

Human papillomavirus e7 oncoprotein transgenic skin develops an enhanced inflammatory response to 2,4-dinitrochlorobenzene by an arginase-1-dependent mechanism.  

PubMed

We have shown that the expression of human papillomavirus type 16 E7 (HPV16.E7) protein within epithelial cells results in local immune suppression and a weak and ineffective immune response to E7 similar to that occuring in HPV-associated premalignancy and cancers. However, a robust acute inflammatory stimulus can overcome this to enable immune elimination of HPV16.E7-transformed epithelial cells. 2,4-Dinitrochlorobenzene (DNCB) can elicit acute inflammation and it has been shown to initiate the regression of HPV-associated genital warts. Although the clinical use of DNCB is discouraged owing to its mutagenic potential, understanding how DNCB-induced acute inflammation alters local HPV16.E7-mediated immune suppression might lead to better treatments. Here, we show that topical DNCB application to skin expressing HPV16.E7 as a transgene induces a hyperinflammatory response, which is not seen in nontransgenic control animals. The E7-associated inflammatory response is characterized by enhanced expression of Th2 cytokines and increased infiltration of CD11b(+)Gr1(int)F4/80(+)Ly6C(hi)Ly6G(low) myeloid cells, producing arginase-1. Inhibition of arginase with an arginase-specific inhibitor, N(omega)-hydroxy-nor-L-arginine, ameliorates the DNCB-induced inflammatory response. Our results demonstrate that HPV16.E7 protein enhances DNCB-associated production of arginase-1 by myeloid cells and consequent inflammatory cellular infiltration of skin. PMID:24732401

Tran, Le Son; Bergot, Anne-Sophie; Mattarollo, Stephen R; Mittal, Deepak; Frazer, Ian H

2014-09-01

30

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

SciTech Connect

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

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

1995-12-31

31

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. PMID:16188983

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

2005-01-01

32

Analysis of the p53-mediated G1 growth arrest pathway in cells expressing the human papillomavirus type 16 E7 oncoprotein.  

PubMed Central

Cells expressing human papillomavirus type 16 (HPV-16) E7, similar to those which express HPV-16 E6, are resistant to a p53-mediated G1 growth arrest. We examined the p53-mediated DNA damage response pathway in E7-expressing cells to determine the mechanism by which E7-containing cells continue to cycle. In response to DNA damage, no dramatic difference was detected in G1- or S-phase cyclin or cyclin-dependent kinase (Cdk) levels when E7-expressing cells were compared to the parental cell line, RKO. Furthermore, Cdk2 kinase activity was inhibited in both RKO cells and E7-expressing cells, while Cdk2 remained active in E6-expressing cells. However, the steady-state levels of pRB and p107 protein were substantially lower in E7-expressing cells than in the parental RKO cells or E6-expressing cells. There was no reduction in pRB mRNA levels, but the half-life of pRB in E7-expressing cells was markedly shorter. Infection of primary human foreskin keratinocytes with recombinant retroviruses expressing HPV-16 E7 resulted in a decrease in pRB protein levels, indicating this phenomenon is a consequence of E7 expression, not of immortalization or transformation. These data strongly suggest E7 interferes with the stability of pRB and p107 protein. We propose that the removal of these components of the p53-mediated G1 growth arrest pathway in E7-expressing cells contributes to the ability of E7 to overcome a p53-mediated G1 growth arrest. PMID:9060648

Jones, D L; Munger, K

1997-01-01

33

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

2013-11-01

34

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

2012-01-01

35

Human T-cell leukemia virus type 1 Tax oncoprotein induces and interacts with a multi-PDZ domain protein, MAGI3  

Microsoft Academic Search

Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia (ATL), whereas the closely related virus HTLV-2 has not been associated with such malignant conditions. HTLV-1 Tax1 oncoprotein transforms a rat fibroblast cell line (Rat-1) much more efficiently than does HTLV-2 Tax2. By using a differential display analysis, we isolated MAGI-3 as a Tax1-inducible gene

Minako Ohashi; Mamoru Sakurai; Masaya Higuchi; Naoki Mori; Masaya Fukushi; Masayasu Oie; Robert J Coffey; Kenta Yoshiura; Yuetsu Tanaka; Makoto Uchiyama; Masakazu Hatanaka; Masahiro Fujii

2004-01-01

36

Papillomavirus E6 oncoproteins  

PubMed Central

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

Vande Pol, Scott B.; Klingelhutz, Aloysius J.

2013-01-01

37

Down-regulation of lipid raft-associated onco-proteins via cholesterol-dependent lipid raft internalization in docosahexaenoic acid-induced apoptosis.  

PubMed

Lipid rafts, plasma membrane microdomains, are important for cell survival signaling and cholesterol is a critical lipid component for lipid raft integrity and function. DHA is known to have poor affinity for cholesterol and it influences lipid rafts. Here, we investigated a mechanism underlying the anti-cancer effects of DHA using a human breast cancer cell line, MDA-MB-231. We found that DHA decreased cell surface levels of lipid rafts via their internalization, which was partially reversed by cholesterol addition. With DHA treatment, caveolin-1, a marker for rafts, and EGFR were colocalized with LAMP-1, a lysosomal marker, in a cholesterol-dependent manner, indicating that DHA induces raft fusion with lysosomes. DHA not only displaced several raft-associated onco-proteins, including EGFR, Hsp90, Akt, and Src, from the rafts but also decreased total levels of those proteins via multiple pathways, including the proteasomal and lysosomal pathways, thereby decreasing their activities. Hsp90 overexpression maintained its client proteins, EGFR and Akt, and attenuated DHA-induced cell death. In addition, overexpression of Akt or constitutively active Akt attenuated DHA-induced apoptosis. All these data indicate that the anti-proliferative effect of DHA is mediated by targeting of lipid rafts via decreasing cell surface lipid rafts by their internalization, thereby decreasing raft-associated onco-proteins via proteasomal and lysosomal pathways and decreasing Hsp90 chaperone function. PMID:24120917

Lee, Eun Jeong; Yun, Un-Jung; Koo, Kyung Hee; Sung, Jee Young; Shim, Jaegal; Ye, Sang-Kyu; Hong, Kyeong-Man; Kim, Yong-Nyun

2014-01-01

38

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

PubMed Central

SUMMARY 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.

2013-01-01

39

Rcl, a Novel Breast Cancer Oncoprotein.  

National Technical Information Service (NTIS)

Rcl is an undefined protein whose expression can be induced by the oncoproteins c-Myc and HER2/Neu, both of which are heavily implicated in breast tumorigenesis. As such, Rcl may be an important downstream effector of c-Myc and HER2/Neu in breast cancer. ...

R. Janknecht

2004-01-01

40

Reactive oxygen species mediate N-(4-hydroxyphenyl)retinamide-induced cell death in malignant T cells and are inhibited by the HTLV-I oncoprotein Tax.  

PubMed

N-(4-hydroxyphenyl)retinamide (HPR) is a synthetic retinoid that inhibits growth of many human tumor cells, including those resistant to natural retinoids. HPR is an effective chemopreventive agent for prostate, cervix, breast, bladder, skin and lung cancers, and has shown promise for the treatment of neuroblastomas. We have previously shown that HPR inhibits proliferation and induces apoptosis of human T-cell lymphotropic virus type I (HTLV-I)-associated adult T-cell leukemia (ATL) and HTLV-I-negative malignant T cells, whereas no effect is observed on normal lymphocytes. In this report, we identified HPR-induced reactive oxygen species (ROS) generation as the key mediator of cell cycle arrest and apoptosis of malignant T cells. HPR treatment of HTLV-I-negative malignant T cells was associated with a rapid and progressive ROS accumulation. Pre-treatment with the antioxidants vitamin C and dithiothreitol inhibited ROS generation, prevented HPR-induced ceramide accumulation, cell cycle arrest, cytochrome c release, caspase-activation and apoptosis. Therefore, anti-oxidants protected malignant T cells from HPR-induced growth inhibition. The expression of the HTLV-I oncoprotein Tax abrogated HPR-induced ROS accumulation in HTLV-I-infected cells, which explains their lower sensitivity to HPR. Defining the mechanism of free radical induction by HPR may support a potential therapeutic role for this synthetic retinoid in ATL and HTLV-I-negative T-cell lymphomas. PMID:17122865

Darwiche, N; Abou-Lteif, G; Bazarbachi, A

2007-02-01

41

The human oncoprotein MDM2 induces replication stress eliciting early intra-S-phase checkpoint response and inhibition of DNA replication origin firing.  

PubMed

Conventional paradigm ascribes the cell proliferative function of the human oncoprotein mouse double minute2 (MDM2) primarily to its ability to degrade p53. Here we report that in the absence of p53, MDM2 induces replication stress eliciting an early S-phase checkpoint response to inhibit further firing of DNA replication origins. Partially synchronized lung cells cultured from p53-/-:MDM2 transgenic mice enter S phase and induce S-phase checkpoint response earlier than lung cells from p53-/- mice and inhibit firing of DNA replication origins. MDM2 activates chk1 phosphorylation, elevates mixed lineage lymphoma histone methyl transferase levels and promotes checkpoint-dependent tri-methylation of histone H3 at lysine 4, known to prevent firing of late replication origins at the early S phase. In the absence of p53, a condition that disables inhibition of cyclin A expression by MDM2, MDM2 increases expression of cyclin D2 and A and hastens S-phase entry of cells. Consistently, inhibition of cyclin-dependent kinases, known to activate DNA replication origins during firing, inhibits MDM2-mediated induction of chk1 phosphorylation indicating the requirement of this activity in MDM2-mediated chk1 phosphorylation. Our data reveal a novel pathway, defended by the intra-S-phase checkpoint, by which MDM2 induces unscheduled origin firing and accelerates S-phase entry of cells in the absence of p53. PMID:24163099

Frum, Rebecca A; Singh, Shilpa; Vaughan, Catherine; Mukhopadhyay, Nitai D; Grossman, Steven R; Windle, Brad; Deb, Sumitra; Deb, Swati Palit

2014-01-01

42

Development of a DNA Vaccine Targeting Human Papillomavirus Type 16 Oncoprotein E6  

Microsoft Academic Search

Human papillomavirus (HPV), particularly type 16 (HPV-16), is present in more than 99% of cervical cancers. The HPV oncoproteins E6 and E7 are constantly expressed and therefore represent ideal targets for HPV vaccine development. We previously developed DNA vaccines encoding calreticulin (CRT) linked to HPV-16 E7 and generated potent E7-specific CD8 T-cell immune responses and antitumor effects against an E7-expressing

Shiwen Peng; Hongxiu Ji; Cornelia Trimble; Liangmei He; Ya-Chea Tsai; Jessica Yeatermeyer; David A. K. Boyd; Chien-Fu Hung; T.-C. Wu

2004-01-01

43

Study of immortalization and malignant transformation of human embryonic esophageal epithelial cells induced by HPV18 E6E7.  

PubMed

In order to study the effect of viruses and tumor promoters on the tumorigenicity of the esophagus, human embryonic esophageal epithelial cells were infected with human papilloma virus HPV18 E6E7-AAV in synergy with 12-O-tetradecanoylphorbol 13-acetate (TPA) to observe their malignant transformation. The cultured esophageal epithelial cells incubated with HPV18 E6E7-AAV were divided into two groups: the SHEEC1 group was exposed to TPA (5 ng/ml) for 4 weeks at the 5th passage of the cells; the SHEE group served as the control and was cultured in the same medium without TPA. The morphological phenotype, the DNA content during the cell cycle and the chromosomes were analyzed. The tumorigenicity was assessed by colony formation after cultivation in soft agar and transplanting the cells into nude mice. HPV18 E6E7 DNA was assayed by fluorescent in situ hybridization (FISH) and the polymerase chain reaction (PCR). The SHEE group, at its 20th passage, grew as a monolayer with the cells showing anchorage dependence and contact inhibition. The chromosome analysis showed diploidy, and soft-agar cultivation and injection into nude mice showed the cells to be non-tumorigenic. They were therefore immortalized cells. In contrast, the SHEEC1 group (TPA group) showed increased DNA synthesis and a proliferative index that was higher (45%) than that of the SHEE group (34%). The number of large colonies of dense multilayer cells (positively transformed foci) in soft agar was high in SHEEC1 group (4.0%) but low in the SHEE group (0.1%). Tumors resulting from transplantation were observed in all six nude mice injected subcutaneously with cells of the SHEEC1 group but no tumor developed in mice receiving cells of the SHEE group. In both groups of cells, HPV18 E6E7 DNA was positively detected by FISH and PCR. The malignant transformation of human embryonic epithelial cells was induced in vitro by HPV18 E6E7 in synergy with TPA. This is a good evidence for the close relationship between HPV and the etiology and pathogenicity of esophageal carcinoma. It is also a reliable model for studying the cellular and molecular mechanisms of carcinogenesis of esophageal carcinoma. PMID:11043396

Shen, Z; Cen, S; Shen, J; Cai, W; Xu, J; Teng, Z; Hu, Z; Zeng, Y

2000-10-01

44

Human papillomavirus type 45 E7 is a transforming protein inducing retinoblastoma protein degradation and anchorage-independent cell cycle progression.  

PubMed

High-risk human papillomaviruses (HPV) cause cervical cancer. The biological properties of HPV-45, the third most prevalent high-risk HPV-genotype, are unknown. We demonstrate here that the HPV-45 E7 protein transforms immortalized NIH3T3 fibroblasts, while mutations in either the conserved LXCXE sequence (C28G) or the carboxyl-terminus (Delta87LQQLF91) significantly abolish this activity. To address the mechanisms underlying cell transformation by HPV-45 E7, we investigated its impact on the cell cycle. We show that HPV-45 E7 associates with the hypophosphorylated form of the retinoblastoma protein (pRb) and induces a significant reduction in the pRb half-life which can be blocked by epoxomicin. Moreover, HPV-45 E7 induces anchorage-independent cell cycle progression of NIH3T3 cells and extends the lifespan of primary human keratinocytes. HPV-45 E7C28G did not bind pRb and could neither induce pRb-proteolysis nor promote cell cycle progression. HPV-45 E7Delta87LQQLF91 had intermediate pRb-binding affinity and retained a residual activity to induce the degradation of pRb but lost the capability to promote cell cycle progression in suspension. Another carboxyl-terminal mutant, HPV-45 E7Delta81AEDL84, showed a trend to reduced transforming activity, had reduced pRb-binding activity and lost the capability to induce pRb-degradation; however, this mutant could induce anchorage-independent cell cycle progression with the same efficiency as HPV-45 E7 wild type. In summary, these data suggest that HPV-45 E7 is a transforming protein and that abrogation of cell cycle control contributes to its oncogenic potential. PMID:18649911

Morandell, Dieter; Rostek, Ursula; Bouvard, Veronique; Campo-Fernández, Beatriz; Fiedler, Marc; Jansen-Dürr, Pidder; Zwerschke, Werner

2008-09-15

45

HTLV-1 Tax oncoprotein inhibits the estrogen-induced-ER ?-Mediated BRCA1 expression by interaction with CBP/p300 cofactors.  

PubMed

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

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

2014-01-01

46

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

PubMed Central

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

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

2014-01-01

47

Expression of LIGHT/TNFSF14 Combined with Vaccination against Human Papillomavirus Type 16 E7 Induces Significant Tumor Regression  

PubMed Central

LIGHT, a ligand for the lymphotoxin-beta receptor, establishes lymphoid-like tissues inside tumor sites and recruits naďve 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 HPV16-induced tumors. Our data show that forced expression of LIGHT in tumors results in an increase in expression of interferon gamma (IFNg) and chemottractant cytokines such as IL-1a, MIG and MIP-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 upon 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 pre-clinical 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

2010-01-01

48

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

49

Disruption of HPV16-E7 by CRISPR/Cas System Induces Apoptosis and Growth Inhibition in HPV16 Positive Human Cervical Cancer Cells  

PubMed Central

High-risk human papillomavirus (HR-HPV) has been recognized as a major causative agent for cervical cancer. Upon HPV infection, early genes E6 and E7 play important roles in maintaining malignant phenotype of cervical cancer cells. By using clustered regularly interspaced short palindromic repeats- (CRISPR-) associated protein system (CRISPR/Cas system), a widely used genome editing tool in many organisms, to target HPV16-E7 DNA in HPV positive cell lines, we showed for the first time that the HPV16-E7 single-guide RNA (sgRNA) guided CRISPR/Cas system could disrupt HPV16-E7 DNA at specific sites, inducing apoptosis and growth inhibition in HPV positive SiHa and Caski cells, but not in HPV negative C33A and HEK293 cells. Moreover, disruption of E7 DNA directly leads to downregulation of E7 protein and upregulation of tumor suppressor protein pRb. Therefore, our results suggest that HPV16-E7 gRNA guided CRISPR/Cas system might be used as a therapeutic strategy for the treatment of cervical cancer. PMID:25136604

Hu, Zheng; Yu, Lan; Zhu, Da; Ding, Wencheng; Wang, Xiaoli; Zhang, Changlin; Wang, Liming; Jiang, Xiaohui; Shen, Hui; He, Dan; Li, Kezhen; Xi, Ling; Ma, Ding; Wang, Hui

2014-01-01

50

A single-codon mutation converts HPV16 E6 oncoprotein into a potential tumor suppressor, which induces p53-dependent senescence of HPV-positive HeLa cervical cancer cells.  

PubMed

High-risk mucosal human papillomaviruses (HPV), mainly HPV16 and HPV18, are implicated in cervical carcinogenesis. HPV16 E6 oncoprotein binds and often targets for degradation numerous cell proteins, including the tumor suppressor p53 and several PDZ domain proteins. Here, we show that a single-point mutation, F47R, is sufficient to convert the HPV16 E6 oncoprotein into a suppressor of HPV-positive HeLa cervical cancer cells proliferation. The E6 F47R mutant is defective for polyubiquitination and subsequent degradation of p53. When expressed in HPV-positive cervical cancer cells, E6 F47R acts as a dominant negative mutant by counteracting the p53 degradation activity of endogenous E6 and restoring high p53 protein levels. Moreover, the prolonged expression of E6 F47R leads to suppression of HeLa cells proliferation through the induction of premature senescence. This phenotype is independent on the PDZ-binding activity of E6. F47R-senescent HeLa cells exhibit a sustained expression of p53, hMDM2 and p21(CIP) proteins and a reduced expression of endogenous HPV18 E6 protein. Finally, small interfering RNAs directed against p53 counteract the effect of E6 F47R expression, indicating that E6 F47R-induced cellular senescence is strongly dependent on p53 signaling pathway. PMID:19015633

Ristriani, T; Fournane, S; Orfanoudakis, G; Travé, G; Masson, M

2009-02-01

51

Kinase requirements in human cells: II. Genetic interaction screens identify kinase requirements following HPV16 E7 expression in cancer cells  

Microsoft Academic Search

Human papillomavirus (HPV) oncoproteins subvert cellular signaling pathways, including kinase pathways, during the carcinogenic process. To identify kinases targeted by the HPV16 E7 oncoprotein, shRNA kinase screens were performed in RKO colorectal carcinoma cell lines that differ only in their expression of HPV16 E7. Our screens identified kinases that were essential for the survival of RKO cells, but not essential

Amy Baldwin; Wenliang Li; Miranda Grace; Joseph Pearlberg; Ed Harlow; Karl Münger; Dorre A. Grueneberg

2008-01-01

52

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. PMID:22318732

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

2012-01-01

53

E6 and E7 from beta HPV38 cooperate with ultraviolet light in the development of actinic keratosis-like lesions and squamous cell carcinoma in mice.  

PubMed

Cutaneous beta human papillomavirus (HPV) types appear to be involved in the development of non-melanoma skin cancer (NMSC); however, it is not entirely clear whether they play a direct role. We have previously shown that E6 and E7 oncoproteins from the beta HPV type 38 display transforming activities in several experimental models. To evaluate the possible contribution of HPV38 in a proliferative tissue compartment during carcinogenesis, we generated a new transgenic mouse model (Tg) where HPV38 E6 and E7 are expressed in the undifferentiated basal layer of epithelia under the control of the Keratin 14 (K14) promoter. Viral oncogene expression led to increased cellular proliferation in the epidermis of the Tg animals in comparison to the wild-type littermates. Although no spontaneous formation of tumours was observed during the lifespan of the K14 HPV38 E6/E7-Tg mice, they were highly susceptible to 7,12-dimethylbenz(a)anthracene (DMBA)/12-0-tetradecanoylphorbol-13-acetate (TPA) two-stage chemical carcinogenesis. In addition, when animals were exposed to ultraviolet light (UV) irradiation, we observed that accumulation of p21(WAF1) and cell-cycle arrest were significantly alleviated in the skin of Tg mice as compared to wild-type controls. Most importantly, chronic UV irradiation of Tg mice induced the development of actinic keratosis-like lesions, which are considered in humans as precursors of squamous cell carcinomas (SCC), and subsequently of SCC in a significant proportion of the animals. In contrast, wild-type animals subjected to identical treatments did not develop any type of skin lesions. Thus, the oncoproteins E6 and E7 from beta HPV38 significantly contribute to SCC development in the skin rendering keratinocytes more susceptible to UV-induced carcinogenesis. PMID:21779166

Viarisio, Daniele; Mueller-Decker, Karin; Kloz, Ulrich; Aengeneyndt, Birgit; Kopp-Schneider, Annette; Gröne, Hermann-Josef; Gheit, Tarik; Flechtenmacher, Christa; Gissmann, Lutz; Tommasino, Massimo

2011-07-01

54

HPV16 Oncoproteins Promote Cervical Cancer Invasiveness by Upregulating Specific Matrix Metalloproteinases  

PubMed Central

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

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

2013-01-01

55

Cellular immunity induced by a novel HPV18 DNA vaccine encoding an E6/E7 fusion consensus protein in mice and rhesus macaques.  

PubMed

Human papilloma-virus (HPV) infection is the major cause of cervical cancer. HPV18 is the most prevalent high-risk HPV after type 16 that accounts for the largest number of cervical cancer cases worldwide. Currently, although prophylactic vaccines have been developed, there is still an urgent need to develop therapeutic HPV vaccines for targeting tumors post-infection. In this study, we utilize a novel multi-phase strategy for HPV18 antigen development with the goal of increasing anti-HPV18 cellular immunity. Our data show that this construct can induce strong cellular immune responses against HPV18 E6 and E7 antigens in a murine model. Moreover, when applied to rhesus monkeys, this construct is also able to elicit cellular immunity. These data suggest such DNA immunogens are candidates for further study in the eventual context of immunotherapy for HPV-associated cancers. PMID:18455277

Yan, Jian; Harris, Kristina; Khan, Amir S; Draghia-Akli, Ruxandra; Sewell, Duane; Weiner, David B

2008-09-19

56

Neuroepithelial carcinomas in mice transgenic with human papillomavirus type 16 E6/E7 ORFs.  

PubMed Central

The effect of the human papillomavirus (HPV) oncogenes E6 and E7 was examined in transgenic mice with a construct containing the human beta-actin promoter regulating HPV16 E6 and E7 open reading frames. In the sole line of mice that transmitted the transgene, neuroepithelial tumors appeared at 2.5 months of life, and by 10 months, 87 of 122 (71%) of the animals were dead from brain tumors. The most frequent type of tumor (74%) was an anaplastic neuroepithelial tumor associated with the ependyma of the third and fourth ventricles, which locally invaded adjacent brain tissue and spread for considerable distances along the ventricular surface. The other two types of tumor were well-differentiated choroid plexus carcinomas (26%) and rare pituitary carcinomas (8.7%). HPV16 E6 RNA and E7 oncoprotein expression were demonstrated in tumor tissue and primary cell lines derived from the tumors. Examination of two tumor suppressor gene products, the retinoblastoma protein and p53, known to bind to HPV16 E7 and E6 oncoproteins, respectively, showed both were expressed in the primary tumor cell lines. These data support a causative role for the HPV oncoproteins in epithelial carcinogenesis. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:8386443

Arbeit, J. M.; Munger, K.; Howley, P. M.; Hanahan, D.

1993-01-01

57

A Novel Mucosal Vaccine Based on Live Lactococci Expressing E7 Antigen and IL12 Induces Systemic and Mucosal Immune Responses and Protects Mice against Human Papillomavirus Type 16Induced Tumors  

Microsoft Academic Search

Current strategies to prevent or treat human papillomavirus type 16 (HPV-16) infection are promising, but remain costly. More economical but efficient vaccines are thus needed. In this study, we evaluated the protective effects of mucosally coadministered live Lactococcus lactis strains expressing cell wall-anchored E7 Ag and a secreted form of IL-12 to treat HPV-16-induced tumors in a murine model. When

Luis G. Bermudez-Humaran; Naima G. Cortes-Perez; Francois Lefevre; Sylvie Rabot; Juan M. Alcocer-Gonzalez; Jean-Jacques Gratadoux; Cristina Rodriguez-Padilla; Reyes S. Tamez-Guerra; Gerard Corthier; Alexandra Gruss; Philippe Langella

2005-01-01

58

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

59

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

PubMed

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

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

2011-08-01

60

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

PubMed

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 to calreticulin (CRT) are capable of enhancing the E7-specific CD+ T-cell immune responses and antitumor effects against E7-expressing tumors. It has also been shown that cluster (short-interval) DNA vaccination regimen generates potent immune responses in a minimal time frame. Thus, in the current study we hypothesize that the cluster intradermal CRT/E7 DNA vaccination will generate significant antigen-specific CD8+ T-cell infiltrates in E7-expressing tumors in tumor-bearing mice, leading to an increase in apoptotic tumor cell death. We found that cluster intradermal CRT/E7 DNA vaccination is capable of rapidly generating a significant number of E7-specific CD8+ T cells, resulting in significant therapeutic antitumor effects in vaccinated mice. We also observed that cluster intradermal CRT/E7 DNA vaccination in the presence of tumor generates significantly higher E7-specific CD8+ T-cell immune responses in the systemic circulation as well as in the tumors. In addition, this vaccination regimen also led to significantly lower levels of CD4+Foxp3+ T-regulatory cells and myeloid suppressor cells compared to vaccination with CRT DNA in peripheral blood and in tumor-infiltrating lymphocytes, resulting in an increase in apoptotic tumor cell death. Thus, our study has significant potential for future clinical translation. PMID:18401437

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

2008-08-01

61

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

PubMed

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

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

2014-07-10

62

Mutational analysis of human papillomavirus type 16 E7 functions.  

PubMed Central

The human papillomavirus type 16 E7 gene encodes a nuclear oncoprotein (98 amino acids [AAs] long) consisting of three regions: regions 1 (AAs 1 to 20) and 2 (AAs 21 to 40), which show high homology to the sequences of conserved domains 1 and 2, respectively, of adenovirus E1A; and region 3 (AAs 41 to 98) containing two metal-binding motifs Cys-X-X-Cys (AAs 58 and 91 to 94). We constructed AA deletion (substitution) mutants and single-AA substitution mutants of E7 placed under the control of the simian virus 40 promoter and examined their biological functions. Stable expression of E7 protein in monkey COS-1 cells required almost the entire length of E7 and was markedly lowered by the mutations in region 3. Transactivation of the adenovirus E2 promoter in monkey CV-1 cells was lowered by the mutations. It was abolished by changing Cys-24 to Gly and markedly decreased by a mutation at His-2 or at the metal-binding motifs in region 3. Focal transformation of rat 3Y1 cells by E7 was eliminated by changing His-2 to Asp or Cys-24 to Gly and was greatly impaired by changing Cys-61 or Cys-94 to Gly. The transforming function survived mutations at Leu-13 and Cys-68 and deletion of Asp-Ser-Ser (AAs 30 to 32). The data suggest that regions 1 to 3 are required for its functions and that the meta-binding motifs in region 3 are required to maintain a stable or functional structure of the E7 protein. Images PMID:2152813

Watanabe, S; Kanda, T; Sato, H; Furuno, A; Yoshiike, K

1990-01-01

63

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

PubMed Central

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

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

2014-01-01

64

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

65

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

66

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

Microsoft Academic Search

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

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

2008-01-01

67

Structural Insights into a Wildtype Domain of the Oncoprotein E6 and Its Interaction with a PDZ Domain  

PubMed Central

The high-risk human papilloma virus (HPV) oncoproteins E6 and E7 interact with key cellular regulators and are etiological agents for tumorigenesis and tumor maintenance in cervical cancer and other malignant conditions. E6 induces degradation of the tumor suppressor p53, activates telomerase and deregulates cell polarity. Analysis of E6 derived from a number of high risk HPV finally yielded the first structure of a wild-type HPV E6 domain (PDB 2M3L) representing the second zinc-binding domain of HPV 51 E6 (termed 51Z2) determined by NMR spectroscopy. The 51Z2 structure provides clues about HPV-type specific structural differences between E6 proteins. The observed temperature sensitivity of the well-folded wild-type E6 domain implies a significant malleability of the oncoprotein in vivo. Hence, the structural differences between individual E6 and their malleability appear, together with HPV type-specific surface exposed side-chains, to provide the structural basis for the different interaction networks reported for individual E6 proteins. Furthermore, the interaction of 51Z2 with a PDZ domain of hDlg was analyzed. Human Dlg constitutes a prototypic representative of the large family of PDZ proteins regulating cell polarity, which are common targets of high-risk HPV E6. Nine C-terminal residues of 51Z2 interact with the second PDZ domain of hDlg2. Surface plasmon resonance in conjunction with the NMR spectroscopy derived complex structure (PDB 2M3M) indicate that E6 residues N-terminal to the canonical PDZ-BM of E6 significantly contribute to this interaction and increase affinity. The structure of the complex reveals how residues outside of the classical PDZ-BM enhance the affinity of E6 towards PDZ domains. Such mechanism facilitates successful competition of E6 with cellular PDZ-binding proteins and may apply to PDZ-binding proteins of other viruses as well. PMID:23638119

Mischo, Andre; Ohlenschlager, Oliver; Hortschansky, Peter; Ramachandran, Ramadurai; Gorlach, Matthias

2013-01-01

68

Structural insights into a wildtype domain of the oncoprotein E6 and its interaction with a PDZ domain.  

PubMed

The high-risk human papilloma virus (HPV) oncoproteins E6 and E7 interact with key cellular regulators and are etiological agents for tumorigenesis and tumor maintenance in cervical cancer and other malignant conditions. E6 induces degradation of the tumor suppressor p53, activates telomerase and deregulates cell polarity. Analysis of E6 derived from a number of high risk HPV finally yielded the first structure of a wild-type HPV E6 domain (PDB 2M3L) representing the second zinc-binding domain of HPV 51 E6 (termed 51Z2) determined by NMR spectroscopy. The 51Z2 structure provides clues about HPV-type specific structural differences between E6 proteins. The observed temperature sensitivity of the well-folded wild-type E6 domain implies a significant malleability of the oncoprotein in vivo. Hence, the structural differences between individual E6 and their malleability appear, together with HPV type-specific surface exposed side-chains, to provide the structural basis for the different interaction networks reported for individual E6 proteins. Furthermore, the interaction of 51Z2 with a PDZ domain of hDlg was analyzed. Human Dlg constitutes a prototypic representative of the large family of PDZ proteins regulating cell polarity, which are common targets of high-risk HPV E6. Nine C-terminal residues of 51Z2 interact with the second PDZ domain of hDlg2. Surface plasmon resonance in conjunction with the NMR spectroscopy derived complex structure (PDB 2M3M) indicate that E6 residues N-terminal to the canonical PDZ-BM of E6 significantly contribute to this interaction and increase affinity. The structure of the complex reveals how residues outside of the classical PDZ-BM enhance the affinity of E6 towards PDZ domains. Such mechanism facilitates successful competition of E6 with cellular PDZ-binding proteins and may apply to PDZ-binding proteins of other viruses as well. PMID:23638119

Mischo, André; Ohlenschläger, Oliver; Hortschansky, Peter; Ramachandran, Ramadurai; Görlach, Matthias

2013-01-01

69

The papillomavirus E7 proteins  

PubMed Central

E7 is an accessory protein that is not encoded by all papillomaviruses. The E7 amino terminus contains two regions of similarity to conserved regions 1 and 2 of the adenovirus E1A protein, which are also conserved in the simian vacuolating virus 40 large tumor antigen. The E7 carboxyl terminus consists of a zinc-binding motif, which is related to similar motifs in E6 proteins. E7 proteins play a central role in the human papillomavirus life cycle, reprogramming the cellular environment to be conducive to viral replication. E7 proteins encoded by the cancer-associated alpha human papillomaviruses have potent transforming activities, which together with E6, are necessary but not sufficient to render their host squamous epithelial cell tumorigenic. This article strives to provide a comprehensive summary of the published research studies on human papillomavirus E7 proteins. PMID:23731972

Roman, Ann; Munger, Karl

2013-01-01

70

Identification of a naturally processed HLA-A*0201 HPV18 E7 T cell epitope by tumor cell mediated in vitro vaccination.  

PubMed

Immunotherapy of HPV-associated disease such as cervical cancer is moving from preclinical investigation to clinical trials. The viral oncoproteins E6 and E7 are ideal target antigens because their expression is mandatory in HPV-transformed tumor cells. T cells are the most important effector cells for therapeutic vaccination strategies. Therefore, the identification and characterization of HPV E6 and E7 T cell epitopes is necessary. Methods to date rely on screening for immunogenicity of peptides predicted by algorithms. Presentation of the identified peptides on tumor cells, however, needs to be confirmed. In our study, we have improved the method to identify peptide epitopes of HPV18 E7 that are actually presented by tumor cells. We induced allogeneic T-cell lines by stimulation with HPV18-positive, CD80 and HLA-A*0201 transfected cervical cancer cells. Sensitized T cells were probed against an array of a HPV18 E7 20mer peptide-library. We found specific reactivity to one of the 20mer peptides. This sequence was then screened via algorithms for putative epitopes. One putative HLA-A2 restricted epitope was confirmed to bind to HLA-A2, to be immunogenic and to induce IFN gamma-release in ELISpot assays. Epitope-specific T cells were cytolytic toward autologous peptide pulsed targets and HPV18 transformed tumor cells. The identification of epitope-specific T cells in tumor infiltrating lymphocytes of a HPV18-positive HLA-matched cervical cancer patient suggests an in vivo relevance of the identified epitope. We suggest that our approach is advantageous over conventional methods, because it yields candidate peptides that are relevant CTL epitopes that are expressed, processed and presented by tumor cells. PMID:12569558

Kather, Angela; Ferrara, Alfonso; Nonn, Marion; Schinz, Manuela; Nieland, John; Schneider, Achim; Dürst, Matthias; Kaufmann, Andreas M

2003-04-10

71

Enhancement of Ad-CRT/E7-Mediated Antitumor Effect by Preimmunization with L. lactis Expressing HPV-16 E7.  

PubMed

Abstract Although current polyvalent vaccines can prevent development of cervical cancer, they cannot be used to treat patients who already have the disease. Adenovirus expressing calreticulin-E7 (Ad-CRT-E7) has shown promising results in the cervical cancer murine model. We also demonstrated that immunization with Lactococcus lactis encoding HPV-16 E7 (Ll-E7) anchored to its surface induces significant HPV-16 E7-specific immune response. Here, we assessed the combination of both approaches in the treatment of a cervical cancer animal model. Intranasal preimmunization of Ll-E7, followed by a single Ad-CRT/E7 application, induced ?80% of tumor suppression in comparison with controls. Mice treated with a combination of Ll-E7 and Ad-CRT/E7 resulted in a 70% survival rate 300 days post-treatment, whereas 100% of the mice in the control groups died by 50 days. Significant CD8+ cytotoxic T-lymphocytes infiltration was detected in the tumors of mice treated with Ll-E7+Ad-CRT/E7. Tumors with regression showed a greater number of positive cells for in situ TUNEL staining than controls. Our results suggest that preimmunization with Ll-E7 enhances the Ad-CRT/E7-mediated antitumor effect. This treatment provides an enormous advantage over repeated applications of Ad-CRT/E7 by maintaining the effectiveness of the three-dose application of Ad-CRT/E7, but avoiding the high systemic toxicities associated with such repeat treatments. PMID:25216057

Rangel-Colmenero, Blanca R; Gomez-Gutierrez, Jorge G; Villatoro-Hernández, Julio; Zavala-Flores, Laura M; Quistián-Martínez, Deyanira; Rojas-Martínez, Augusto; Arce-Mendoza, Alma Y; Guzmán-López, Santos; Montes-de-Oca-Luna, Roberto; Saucedo-Cárdenas, Odila

2014-11-01

72

The E6 oncoprotein from HPV16 enhances the canonical Wnt/?-catenin pathway in skin epidermis in vivo.  

PubMed

The contribution of the Wnt signaling pathway to human papilloma virus (HPV)-induced carcinogenesis is poorly understood. In high-grade dysplastic lesions that are caused by high-risk HPVs (HR-HPV), ?-catenin is often located in the cell nucleus, which suggests that Wnt pathway may be involved in the development of HPV-related carcinomas. Most of the oncogenic potential of HR-HPVs resides on the PDZ-binding domain of E6 protein. We hypothesized that the PDZ-binding domain of the HPV16-E6 oncoprotein induces the nuclear accumulation of ?-catenin due to its capacity to degrade PDZ-containing cellular targets. To test this hypothesis, we evaluated the staining pattern of ?-catenin in the skin epidermis of transgenic mice expressing the full-length E6 oncoprotein (K14E6 mice) and measured LacZ gene expression in K14E6 mice that were crossed with a strain expressing LacZ that was knocked into the Axin2 locus (Axin2(+/LacZ) mice). Here, we show that the E6 oncoprotein enhances the nuclear accumulation of ?-catenin, the accumulation of cellular ?-catenin-responsive genes, and the expression of LacZ. None of these effects were observed when a truncated E6 oncoprotein that lacks the PDZ-binding domain was expressed alone (K14E6?PDZ mice) or in combination with Axin2(+/LacZ). Conversely, cotransfection with either E6 or E6?PDZ similarly enhanced canonical Wnt signaling in short-term in vitro assays that used a luciferase Wnt/?-catenin/TCF-dependent promoter. We propose that the activation of canonical Wnt signaling could be induced by the HPV16-E6 oncoprotein; however, the participation of the E6 PDZ-binding domain seems to be important in in vivo models only. PMID:22160870

Bonilla-Delgado, José; Bulut, Gülay; Liu, Xuefeng; Cortés-Malagón, Enoc M; Schlegel, Richard; Flores-Maldonado, Catalina; Contreras, Rubén G; Chung, Sang-Hyuk; Lambert, Paul F; Uren, Aykut; Gariglio, Patricio

2012-02-01

73

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

SciTech Connect

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

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

2008-07-11

74

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

PubMed

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

Boon, Siaw Shi; Banks, Lawrence

2013-02-01

75

Development of a DNA vaccine targeting human papillomavirus type 16 oncoprotein E6.  

PubMed

Human papillomavirus (HPV), particularly type 16 (HPV-16), is present in more than 99% of cervical cancers. The HPV oncoproteins E6 and E7 are constantly expressed and therefore represent ideal targets for HPV vaccine development. We previously developed DNA vaccines encoding calreticulin (CRT) linked to HPV-16 E7 and generated potent E7-specific CD8(+) T-cell immune responses and antitumor effects against an E7-expressing tumor. Since vaccines targeting E6 also represent an important strategy for controlling HPV-associated lesions, we developed a DNA vaccine encoding CRT linked to E6 (CRT/E6). Our results indicated that the CRT/E6 DNA vaccine, but not a wild-type E6 DNA vaccine, generated significant E6-specific CD8(+) T-cell immune responses in vaccinated mice. Mapping of the immunodominant epitope of E6 revealed that an E6 peptide comprising amino acids (aa) 48 to 57 (E6 aa48-57), presented by H-2K(b), is the optimal peptide and that the region of E6 comprising aa 50 to 57 represents the minimal core sequence required for activating E6-specific CD8(+) T lymphocytes. We also demonstrated that E6 aa48-57 contains cytotoxic T-lymphocyte epitopes naturally presented by E6-expressing TC-1 cells. Vaccination with a CRT/E6 but not a CRT/mtE6 (lacking aa 50 to 57 of E6) DNA vaccine could protect vaccinated mice from challenge with E6-expressing TC-1 tumors. Thus, our data indicate that E6 aa48-57 contains the immunodominant epitope and that a CRT/E6 DNA vaccine may be useful for control of HPV infection and HPV-associated lesions. PMID:15280455

Peng, Shiwen; Ji, Hongxiu; Trimble, Cornelia; He, Liangmei; Tsai, Ya-Chea; Yeatermeyer, Jessica; Boyd, David A K; Hung, Chien-Fu; Wu, T-C

2004-08-01

76

Characterization of HLA-A2-restricted HPV16 E7-specific CD8+ T-cell immune responses induced by DNA vaccines in HLA-A2 transgenic mice  

Microsoft Academic Search

We have recently demonstrated that linkage of DNA-encoding calreticulin to DNA-encoding human papillomavirus-16 E7 antigen strongly enhances the efficacy of DNA vaccines against E7-expressing tumors in animal models. In this study, as a prelude to clinical translation, we characterized the ability of DNA-encoding calreticulin linked to DNA-encoding E7 antigen to generate HLA-A2-restricted E7-specific CD8+ T-cell responses in HLA-A2 (AAD) transgenic

S Peng; C Trimble; L He; Y-C Tsai; C-T Lin; D A K Boyd; D Pardoll; C-F Hung; T-C Wu

2006-01-01

77

Characterization of HLA-A2-restricted HPV-16 E7-specific CD8(+) T-cell immune responses induced by DNA vaccines in HLA-A2 transgenic mice.  

PubMed

We have recently demonstrated that linkage of DNA-encoding calreticulin to DNA-encoding human papillomavirus-16 E7 antigen strongly enhances the efficacy of DNA vaccines against E7-expressing tumors in animal models. In this study, as a prelude to clinical translation, we characterized the ability of DNA-encoding calreticulin linked to DNA-encoding E7 antigen to generate HLA-A2-restricted E7-specific CD8(+) T-cell responses in HLA-A2 (AAD) transgenic mice, as well as antitumor effects against an E7(+) HLA-A2(+) tumor cell line, TC-1/A2. Our results show that while vaccination with CRT/E7 DNA generates strong H-2D(b)-restricted E7 (amino acid (aa)49-57)-specific CD8(+) T-cell immune responses in both C57BL/6 and HLA-A2 (AAD) transgenic mice, no such responses were generated to HLA-A2-restricted epitopes in either type of mouse. In contrast, vaccination with DNA-encoding calreticulin linked to DNA encoding a mutant version of E7 with a deleted aa49-57 epitope leads to the generation of an HLA-A2-restricted E7 (aa11-20)-specific CTL response in HLA-A2 (AAD) transgenic mice. More importantly, vaccination with CRT/mtE7 (del aa49-57) DNA protects against a lethal challenge with TC-1/A2 tumor cells in HLA-A2 (AAD) transgenic mice. Furthermore, our in vitro studies demonstrate that the presence of the E7 (aa49-57) epitope does not suppress presentation of the HLA-A2-restricted E7 (aa11-20) epitope through MHC class I molecules. Thus, the predominant E7 aa49-57-specific CD8+ T-cell immune response in HLA-A2 transgenic mice vaccinated with CRT/E7 is likely due to preferred expansion of E7 aa49-57-specific CD8(+) T cells in vaccinated mice. These results highlight the importance of epitope immunodominance in the evaluation of immune responses in HLA-A2 (AAD) transgenic mice. PMID:16107858

Peng, S; Trimble, C; He, L; Tsai, Y-C; Lin, C-T; Boyd, D A K; Pardoll, D; Hung, C-F; Wu, T-C

2006-01-01

78

Activation of Noncanonical NF-?B Signaling by the Oncoprotein Tio*  

PubMed Central

NF-?B transcription factors are key regulators of cellular proliferation and frequently contribute to oncogenesis. The herpesviral oncoprotein Tio, which promotes growth transformation of human T cells in a recombinant herpesvirus saimiri background, potently induces canonical NF-?B signaling through membrane recruitment of the ubiquitin ligase tumor necrosis factor receptor-associated factor 6 (TRAF6). Here, we show that, in addition to Tio-TRAF6 interaction, the Tio-induced canonical NF-?B signal requires the presence of the regulatory subunit of the inhibitor of ?B kinase (IKK) complex, NF-?B essential modulator (NEMO), and the activity of its key kinase, IKK?, to up-regulate expression of endogenous cellular inhibitor of apoptosis 2 (cIAP2) and interleukin 8 (IL-8) proteins. Dependent on TRAF6 and NEMO, Tio enhances the expression of the noncanonical NF-?B proteins, p100 and RelB. Independent of TRAF6 and NEMO, Tio mediates stabilization of the noncanonical kinase, NF-?B-inducing kinase (NIK). Concomitantly, Tio induces efficient processing of the p100 precursor molecule to its active form, p52, as well as DNA binding of nuclear p52 and RelB. In human T cells transformed by infection with a Tio-recombinant virus, sustained expression of p100, RelB, and cIAP2 depends on IKK? activity, yet processing to p52 remains largely unaffected by IKK? inhibition. However, long term inhibition of IKK? disrupts the continuous growth of the transformed cells and induces cell death. Hence, the Tio oncoprotein triggers noncanonical NF-?B signaling through NEMO-dependent up-regulation of p100 precursor and RelB, as well as through NEMO-independent generation of p52 effector. PMID:20353939

de Jong, Sarah Jill; Albrecht, Jens-Christian; Schmidt, Monika; Muller-Fleckenstein, Ingrid; Biesinger, Brigitte

2010-01-01

79

Structural basis for hijacking of cellular LxxLL motifs by papillomavirus E6 oncoproteins  

PubMed Central

E6 viral oncoproteins are key players in epithelial tumors induced by Papillomaviruses in vertebrates, including cervical cancer in humans. E6 proteins target many host proteins by specifically interacting with acidic LxxLL motifs. Here, we solved the crystal structures of Bovine (BPV1) and Human (HPV16) Papillomavirus E6 proteins bound to LxxLL peptides from the focal adhesion protein paxillin and the ubiquitin ligase E6AP, respectively. In both E6 proteins, two zinc domains and a linker helix form a basic-hydrophobic pocket, which captures helical LxxLL motifs in a way compatible with other interaction modes. Mutational inactivation of the LxxLL binding pocket disrupts the oncogenic activities of both E6 proteins. This work reveals the structural basis of both the multifunctionality and the oncogenicity of E6 proteins. PMID:23393263

Zanier, Katia; Charbonnier, Sebastian; Sidi, Abdellahi Ould M'hamed Ould; McEwen, Alastair G.; Ferrario, Maria Giovanna; Poussin, Pierre; Cura, Vincent; Brimer, Nicole; Babah, Khaled Ould; Ansari, Tina; Muller, Isabelle; Stote, Roland H.; Cavarelli, Jean; Pol, Scott Vande; Trave, Gilles

2014-01-01

80

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

SciTech Connect

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

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

2007-10-10

81

Edinburgh Research Explorer Translation elongation factor eEF1A2 is a potential oncoprotein  

E-print Network

Edinburgh Research Explorer Translation elongation factor eEF1A2 is a potential oncoprotein eEF1A2 is a potential oncoprotein that is overexpressed in two-thirds of breast tumours' BMC Cancer number not for citation purposes) BMC Cancer Open AccessResearch article Translation elongation factor eEF

Millar, Andrew J.

82

The Christmas Waltz E7+5 A F#7/A# Bm7 E7  

E-print Network

The Christmas Waltz E7+5 A F#7/A# Bm7 E7 Frosted windowpanes, Candles gleaming inside A A#o Bm7 E7b Christmas Waltz Chord Forms (Key of A) E7+5 1 2 1 1 V A 0 3 2 1 F#7/A# 3 x 1 4 2 x V IV VII Bm7 2 x 3 3 3 x

Fowler, Mark

83

An ELISA capture assay for the E7 transforming proteins of HPV16 and HPV18.  

PubMed

ELISA capture assays were established for the E7 transforming proteins of HPV16 and HPV18, based on a range of previously characterised polyclonal and monoclonal antibodies. No cross-reactivity was observed in the ELISAs between HPV18 E7 and HPV16 E7. Immunoreactive E7 protein (iE7) was measured in a series of HPV-transformed cell lines, and ranged from 0.6 to 17.7 ng iE7/mg cell protein. iE7 was labile at 22 degrees C (t1/2 = 37 min) but relatively more stable at 4 degrees C (t1/2 = 210 min). HPV16 E7 protein at concentrations from 0.10 to 0.69 ng iE7/mg cell protein was detected in 5 of 13 smears from women with abnormal cervical cytology. Assay of E7 protein may play a role in the detection of HPV-induced cervical lesions with malignant potential. PMID:1317876

Selvey, L A; Dunn, L A; Murray, B; Tindle, R W; Frazer, I H

1992-05-01

84

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

Cancer.gov

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

85

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

86

Human papillomavirus (HPV)-18 E6 oncoprotein interferes with the epithelial cell polarity Par3 protein.  

PubMed

High-risk human papillomavirus (HPV) infection is the principal risk factor for the development of cervical cancer. The HPV E6 oncoprotein has the ability to target and interfere with several PSD-95/DLG/ZO-1 (PDZ) domain-containing proteins that are involved in the control of cell polarity. This function can be significant for E6 oncogenic activity because a deficiency in cell polarisation is a marker of tumour progression. The establishment and control of polarity in epithelial cells depend on the correct asymmetrical distribution of proteins and lipids at the cell borders and on specialised cell junctions. In this report, we have investigated the effects of HPV E6 protein on the polarity machinery, with a focus on the PDZ partitioning defective 3 (Par3) protein, which is a key component of tight junctions (TJ) and the polarity network. We demonstrate that E6 is able to bind and induce the mislocalisation of Par3 protein in a PDZ-dependent manner without significant reduction in Par3 protein levels. In addition, the high-risk HPV-18 E6 protein promotes a delay in TJ formation when analysed by calcium switch assays. Taken together, the data presented in this study contribute to our understanding of the molecular mechanism by which HPVs induce the loss of cell polarity, with potential implications for the development and progression of HPV-associated tumours. PMID:24462519

Facciuto, Florencia; Bugnon Valdano, Marina; Marziali, Federico; Massimi, Paola; Banks, Lawrence; Cavatorta, Ana Laura; Gardiol, Daniela

2014-05-01

87

Quercetin elevates p27(Kip1) and arrests both primary and HPV16 E6/E7 transformed human keratinocytes in G1.  

PubMed

Our previous work with primary bovine fibroblasts demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (Pteridium aquilinum), arrested cells in G1 and G2/M, in correlation with p53 activation. The expression of bovine papillomavirus type 4 (BPV-4) E7 overcame this arrest and lead to the development of tumorigenic cells lines (Beniston et al., 2001). Given the possible link between papillomavirus infection, bracken fern in the diet and cancer of the upper gastrointestinal (GI) tract in humans, we investigated whether a similar situation would occur in human cells transformed by human papillomavirus type 16 (HPV-16) oncoproteins. Quercetin arrested primary human foreskin keratinocytes in G1. Arrest was linked to an elevation of the cyclin-dependent kinase inhibitor (cdki) p27(Kip1). Expression of the HPV16 E6 and E7 oncoproteins in transformed cells failed to abrogate cell cycle arrest. G1 arrest in the transformed cells was also linked to an increase of p27(Kip1) with a concomitant reduction of cyclin E-associated kinase activity. This elevation of p27(Kip1) was due not only to increased protein half-life, but also to increased mRNA transcription. PMID:12934110

Beniston, Richard Garry; Campo, Maria Saveria

2003-08-21

88

Cellular localization of BARF1 oncoprotein and its cell stimulating activity in human epithelial cell.  

PubMed

BARF1 gene encoded by Epstein-Barr virus is capable of immortalizing the primary monkey epithelial cells and of inducing malignant transformation in human EBV-negative B cell lines as well as rodent fibroblast. This oncoprotein is a secreted protein capable of acting as a powerful mitogen. We have studied the effect of BARF1 protein in transfected or BARF1 protein treated human HaCaT epithelial cells. In BARF1-transfected cells, cell growth was activated and its protein was found both in culture medium and cellular compartment (membrane, cytoplasm and nuclei). When purified BARF1 protein was exogenously added in the cell culture medium of HaCaT cells in absence of fetal calf serum led to its entrance into cells and its intracellular localization in cytoplasm, nuclear periphery and nuclei at 14h treatment, determined by confocal and immunoelectron microscopy. Cell fractionation confirmed its nuclear localization. Nuclear localization was observed in both systems. More interestingly, purified BARF1 protein p29 exogenously added in the cell culture medium activated cell passage of G1 to S phase. S phase activation by its autocrine activity and its tumorigenic activity would be associated with the development of EBV-associated carcinomas. PMID:23458996

Sakka, Emna; Zur Hausen, Axel; Houali, Karim; Liu, Haying; Fiorini, Sylvie; Ooka, Tadamasa

2013-06-01

89

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

PubMed

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

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

2014-10-01

90

Combination of hTERT and bmi-1, E6, or E7 Induces Prolongation of the Life Span of Bone Marrow Stromal Cells from an Elderly Donor without Affecting Their Neurogenic Potential†  

PubMed Central

Murine bone marrow stromal cells differentiate not only into mesodermal derivatives, such as osteocytes, chondrocytes, adipocytes, skeletal myocytes, and cardiomyocytes, but also into neuroectodermal cells in vitro. Human bone marrow stromal cells are easy to isolate but difficult to study because of their limited life span. To overcome this problem, we attempted to prolong the life span of bone marrow stromal cells and investigated whether bone marrow stromal cells modified with bmi-1, hTERT, E6, and E7 retained their differentiated capability, or multipotency. In this study, we demonstrated that the life span of bone marrow stromal cells derived from a 91-year-old donor could be extended and that the stromal cells with an extended life span differentiated into neuronal cells in vitro. We examined the neuronally differentiated cells morphologically, physiologically, and biologically and compared the gene profiles of undifferentiated and differentiated cells. The neuronally differentiated cells exhibited characteristics similar to those of midbrain neuronal progenitors. Thus, the results of this study support the possible use of autologous-cell graft systems to treat central nervous system diseases in geriatric patients. PMID:15923633

Mori, Taisuke; Kiyono, Tohru; Imabayashi, Hideaki; Takeda, Yukiji; Tsuchiya, Kohei; Miyoshi, Shunichirou; Makino, Hatsune; Matsumoto, Kenji; Saito, Hirohisa; Ogawa, Satoshi; Sakamoto, Michiie; Hata, Jun-Ichi; Umezawa, Akihiro

2005-01-01

91

The HTLV-1 Tax Oncoprotein Represses Ku80 Gene Expression  

PubMed Central

The HTLV-I oncoprotein Tax interferes with DNA double strand break repair. Since non-homologous end joining (NHEJ) is a major pathway used to repair DNA double strand breaks we examined the effect of Tax on this pathway, with particular interest in the expression and function of Ku80, a critical component of the NHEJ pathway. Tax expression decreased Ku80 mRNA and protein levels, and repressed transcription from the Ku80 promoter. Conversely, Ku80 mRNA increased following siRNA knockdown of Tax in HTLV-I infected cells. Tax expression was associated with an elevated number of micronuclei and nucleoplasmic bridges, hallmarks of improper DNA double strand break repair. Our studies identified Tax as a transcriptional repressor of Ku80 that correlates with decreased DNA repair function. The reduction of Ku80 transcription by Tax may deplete the cell of an essential DNA break binding protein, resulting in reduced repair of DNA double strand breaks and accumulation genomic mutations. PMID:21571351

Ducu, Razvan I.; Dayaram, Tajhal; Marriott, Susan J.

2011-01-01

92

NUP98 fusion oncoproteins promote aneuploidy by attenuating the mitotic spindle checkpoint.  

PubMed

NUP98 is a recurrent fusion partner in chromosome translocations that cause acute myelogenous leukemia. NUP98, a nucleoporin, and its interaction partner Rae1, have been implicated in the control of chromosome segregation, but their mechanistic contributions to tumorigenesis have been unclear. Here, we show that expression of NUP98 fusion oncoproteins causes mitotic spindle defects and chromosome missegregation, correlating with the capability of NUP98 fusions to cause premature securin degradation and slippage from an unsatisfied spindle assembly checkpoint (SAC). NUP98 fusions, unlike wild-type NUP98, were found to physically interact with the anaphase promoting complex/cyclosome (APC/C)(Cdc20) and to displace the BubR1 SAC component, suggesting a possible mechanistic basis for their interference with SAC function. In addition, NUP98 oncoproteins displayed a prolonged half-life in cells. We found that NUP98 stability is controlled by a PEST sequence, absent in NUP98 oncoproteins, whose deletion reproduced the aberrant SAC-interfering activity of NUP98 oncoproteins. Together, our findings suggest that NUP98 oncoproteins predispose myeloid cells to oncogenic transformation or malignant progression by promoting whole chromosome instability. PMID:24371226

Salsi, Valentina; Ferrari, Silvia; Gorello, Paolo; Fantini, Sebastian; Chiavolelli, Francesca; Mecucci, Cristina; Zappavigna, Vincenzo

2014-02-15

93

-Arrestin 2 Functions as a G-Protein-coupled Receptor-activated Regulator of Oncoprotein Mdm2*  

E-print Network

(6). Transcription of the Mdm2 gene is strongly stimulated by the activated p53. The Mdm2 protein-Arrestin 2 Functions as a G-Protein-coupled Receptor-activated Regulator of Oncoprotein Mdm2 Oncoprotein Mdm2 is a master negative regulator of the tumor suppressor p53 and has been recently shown

Tian, Weidong

94

Targeting the MUC1-C oncoprotein inhibits self-renewal capacity of breast cancer cells.  

PubMed

The capacity of breast cancer cells to form mammospheres in non-adherent serum-free culture is used as a functional characteristic of the self-renewing stem-like cell population. The present studies demonstrate that silencing expression of the MUC1-C oncoprotein inhibits growth of luminal MCF-7 and HER2-overexpressing SKBR3 breast cancer cells as mammospheres. We also show that triple-negative MDA-MB-468 breast cancer cells are dependent on MUC1-C for growth as mammospheres and tumor xenografts. Similar results were obtained when MUC1-C function was inhibited by expression of a MUC1-C(CQC?AQA) mutant. Moreover, treatment with the MUC1-C inhibitor GO-203, a cell penetrating peptide that binds to the MUC1-C cytoplasmic domain and blocks MUC1-C function, confirmed the importance of this target for self-renewal. The mechanistic basis for these findings is supported by the demonstration that MUC1-C activates NF-?B, occupies the IL-8 promoter with NF-?B, and induces IL-8 transcription. MUC1-C also induces NF-?B-dependent expression of the IL-8 receptor, CXCR1. In concert with these results, targeting MUC1-C with GO-203 suppresses IL-8/CXCR1 expression and disrupts the formation of established mammospheres. Our findings indicate that MUC1-C contributes to the self-renewal of breast cancer cells by activating the NF-?B?IL-8/CXCR1 pathway and that targeting MUC1-C represents a potential approach for the treatment of this population. PMID:24770886

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

2014-05-15

95

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. PMID:8870673

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

1996-01-01

96

PAR1b takes the stage in the morphogenetic and motogenetic activity of Helicobacter pylori CagA oncoprotein  

PubMed Central

Helicobacter pylori CagA oncoprotein is critically involved in gastric carcinogenesis. Upon delivery into gastric epithelial cells via type IV secretion, CagA induces an extremely elongated cell-shape known as the hummingbird phenotype, which is associated with massive changes in actin cytoskeleton and elevated motility. With the notion that the hummingbird phenotype reflects pathogenic/oncogenic activity of CagA, many studies have focused on the mechanism through which CagA induces the morphological change. Once delivered, CagA interacts with host proteins such as oncogenic phosphatase SHP2 and polarity-regulating kinase PAR1b. Whereas the essential role of the CagA-SHP2 interaction in inducing the hummingbird phenotype has been extensively investigated, involvement of the CagA-PAR1b interaction in the morphological change has remained uncertain. Recently, we found that the CagA-PAR1b interaction, which inhibits PAR1b kinase activity, influences the actin cytoskeletal system and potentiates the magnitude of the hummingbird phenotype. We also found that PAR1b inactivates a RhoA-specific GEF, GEF-H1, via phosphorylation and thereby inhibits cortical actin and stress fiber formation. Collectively, these findings indicate that CagA-mediated inhibition of PAR1b promotes RhoA-dependent actin-cytoskeletal rearrangement and thereby strengthens the hummingbird phenotype induced by CagA-stimulated SHP2 during infection with H. pylori cagA-positive strains. PMID:23076215

Yamahashi, Yukie; Hatakeyama, Masanori

2013-01-01

97

Successful therapeutic vaccination with integrase defective lentiviral vector expressing nononcogenic human papillomavirus E7 protein.  

PubMed

Persistent infection with high risk genotypes of human papillomavirus (HPV) is the cause of cervical cancer, one of most common cancer among woman worldwide, and represents an important risk factor associated with other anogenital and oropharyngeal cancers in men and women. Here, we designed a therapeutic vaccine based on integrase defective lentiviral vector (IDLV) to deliver a mutated nononcogenic form of HPV16 E7 protein, considered as a tumor specific antigen for immunotherapy of HPV-associated cervical cancer, fused to calreticulin (CRT), a protein able to enhance major histocompatibility complex class I antigen presentation (IDLV-CRT/E7). Vaccination with IDLV-CRT/E7 induced a potent and persistent E7-specific T cell response up to 1 year after a single immunization. Importantly, a single immunization with IDLV-CRT/E7 was able to prevent growth of E7-expressing TC-1 tumor cells and to eradicate established tumors in mice. The strong therapeutic effect induced by the IDLV-based vaccine in this preclinical model suggests that this strategy may be further exploited as a safe and attractive anticancer immunotherapeutic vaccine in humans. PMID:22700466

Grasso, Felicia; Negri, Donatella R M; Mochi, Stefania; Rossi, Alessandra; Cesolini, Armando; Giovannelli, Andrea; Chiantore, Maria Vincenza; Leone, Pasqualina; Giorgi, Colomba; Cara, Andrea

2013-01-15

98

Influence of single-walled carbon nanotubes (< 0.001 wt %) and/or zwitter-ionic phospholipid (SOPC) surface layer on the behaviour of the gradient flexoelectric and surface induced polarization domains arising in a homeotropic E7 (a mixture of 5CB, 7CB, 8OCB and 5CT) nematic layer  

NASA Astrophysics Data System (ADS)

The influence has been studied of single-walled carbon nanotubes with a concentration between 0.0001 and 0.001 wt % and a dried zwitter-ionic phospholipid (SOPC: l-stearoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine) layer of thickness, smaller than 0.5 ?m, deposited only on a half of one of the two glass plates, on the behaviour of the gradient flexoelectric and surface polarization induced domains arising in a homeotropic nematic E7 (a mixture of 5CB, 7CB, 8OCB and 5CT) layer. We have observed for the first time different polar on/off formation of the surface polarization induced domains in the region of the liquid crystal cell without surface deposited lipid SOPC layer. On the other hand, the SOPC layer strongly decreases the gradient of the electric field thus leading to less-pronounced flexoelectric domains. However, the SOPC layer does not influence the creation of surface polarization induced domains and of injection induced domains arising at voltages above 4V. Appropriate dynamic light transmitted curves have been recorded and typical microphotographs have been taken.

Hinov, H. P.; Pavli?, J. I.; Marinov, Y. G.; Petrov, A. G.; Sridevi, S.; Rafailov, P. M.; Dettlaff-Weglikowska, U.

2010-11-01

99

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

PubMed Central

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

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

2014-01-01

100

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

101

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

102

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

PubMed

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. PMID:19307009

Narayan, Nisha; Subbaiah, Vanitha Krishna; Banks, Lawrence

2009-04-25

103

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

PubMed Central

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

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

2014-01-01

104

Ordered Self-Assembly Mechanism of a Spherical Oncoprotein Oligomer Triggered by Zinc Removal and Stabilized by an Intrinsically Disordered Domain  

PubMed Central

Background Self-assembly is a common theme in proteins of unrelated sequences or functions. The human papillomavirus E7 oncoprotein is an extended dimer with an intrinsically disordered domain, that can form large spherical oligomers. These are the major species in the cytosol of HPV transformed and cancerous cells. E7 binds to a large number of targets, some of which lead to cell transformation. Thus, the assembly process not only is of biological relevance, but represents a model system to investigate a widely distributed mechanism. Methodology/Principal Findings Using various techniques, we monitored changes in secondary, tertiary and quaternary structure in a time course manner. By applying a robust kinetic model developed by Zlotnik, we determined the slow formation of a monomeric “Z-nucleus” after zinc removal, followed by an elongation phase consisting of sequential second-order events whereby one monomer is added at a time. This elongation process takes place at a strikingly slow overall average rate of one monomer added every 28 seconds at 20 µM protein concentration, strongly suggesting either a rearrangement of the growing complex after binding of each monomer or the existence of a “conformation editing” mechanism through which the monomer binds and releases until the appropriate conformation is adopted. The oligomerization determinant lies within its small 5 kDa C-terminal globular domain and, remarkably, the E7 N-terminal intrinsically disordered domain stabilizes the oligomer, preventing an insoluble amyloid route. Conclusion We described a controlled ordered mechanism with features in common with soluble amyloid precursors, chaperones, and other spherical oligomers, thus sharing determining factors for symmetry, size and shape. In addition, such a controlled and discrete polymerization reaction provides a valuable tool for nanotechnological applications. Finally, its increased immunogenicity related to its supramolecular structure is the basis for the development of a promising therapeutic vaccine candidate for treating HPV cancerous lesions. PMID:22590549

Smal, Clara; Alonso, Leonardo G.; Wetzler, Diana E.; Heer, Angeles; de Prat Gay, Gonzalo

2012-01-01

105

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. PMID:22911850

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

106

Selective PDZ protein-dependent stimulation of phosphatidylinositol 3-kinase by the adenovirus E4ORF1 oncoprotein  

Microsoft Academic Search

While PDZ domain-containing proteins represent cellular targets for several different viral oncoproteins, including human papillomavirus E6, human T-cell leukemia virus type 1 Tax, and human adenovirus E4-ORF1, the functional consequences for such interactions have not been elucidated. Here we report that, at the plasma membrane of cells, the adenovirus E4-ORF1 oncoprotein selectively and potently stimulates phosphatidylinositol 3-kinase (PI3K), triggering a

Kristopher K Frese; Siu Sylvia Lee; Darby L Thomas; Isabel J Latorre; Robert S Weiss; Britt A Glaunsinger; Ronald T Javier

2003-01-01

107

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

PubMed Central

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

2014-01-01

108

Epstein - Barr virus transforming protein LMP-1 alters B cells gene expression by promoting accumulation of the oncoprotein ?Np73?.  

PubMed

Many studies have proved that oncogenic viruses develop redundant mechanisms to alter the functions of the tumor suppressor p53. Here we show that Epstein-Barr virus (EBV), via the oncoprotein LMP-1, induces the expression of ?Np73?, a strong antagonist of p53. This phenomenon is mediated by the LMP-1 dependent activation of c-Jun NH2-terminal kinase 1 (JNK-1) which in turn favours the recruitment of p73 to ?Np73? promoter. A specific chemical inhibitor of JNK-1 or silencing JNK-1 expression strongly down-regulated ?Np73? mRNA levels in LMP-1-containing cells. Accordingly, LMP-1 mutants deficient to activate JNK-1 did not induce ?Np73? accumulation. The recruitment of p73 to the ?Np73? promoter correlated with the displacement of the histone-lysine N-methyltransferase EZH2 which is part of the transcriptional repressive polycomb 2 complex. Inhibition of ?Np73? expression in lymphoblastoid cells (LCLs) led to the stimulation of apoptosis and up-regulation of a large number of cellular genes as determined by whole transcriptome shotgun sequencing (RNA-seq). In particular, the expression of genes encoding products known to play anti-proliferative/pro-apoptotic functions, as well as genes known to be deregulated in different B cells malignancy, was altered by ?Np73? down-regulation. Together, these findings reveal a novel EBV mechanism that appears to play an important role in the transformation of primary B cells. PMID:23516355

Accardi, Rosita; Fathallah, Ikbal; Gruffat, Henri; Mariggiň, Giuseppe; Le Calvez-Kelm, Florence; Voegele, Catherine; Bartosch, Birke; Hernandez-Vargas, Hector; McKay, James; Sylla, Bakary S; Manet, Evelyne; Tommasino, Massimo

2013-03-01

109

Epstein - Barr Virus Transforming Protein LMP-1 Alters B Cells Gene Expression by Promoting Accumulation of the Oncoprotein ?Np73?  

PubMed Central

Many studies have proved that oncogenic viruses develop redundant mechanisms to alter the functions of the tumor suppressor p53. Here we show that Epstein-Barr virus (EBV), via the oncoprotein LMP-1, induces the expression of ?Np73?, a strong antagonist of p53. This phenomenon is mediated by the LMP-1 dependent activation of c-Jun NH2-terminal kinase 1 (JNK-1) which in turn favours the recruitment of p73 to ?Np73? promoter. A specific chemical inhibitor of JNK-1 or silencing JNK-1 expression strongly down-regulated ?Np73? mRNA levels in LMP-1-containing cells. Accordingly, LMP-1 mutants deficient to activate JNK-1 did not induce ?Np73? accumulation. The recruitment of p73 to the ?Np73? promoter correlated with the displacement of the histone-lysine N-methyltransferase EZH2 which is part of the transcriptional repressive polycomb 2 complex. Inhibition of ?Np73? expression in lymphoblastoid cells (LCLs) led to the stimulation of apoptosis and up-regulation of a large number of cellular genes as determined by whole transcriptome shotgun sequencing (RNA-seq). In particular, the expression of genes encoding products known to play anti-proliferative/pro-apoptotic functions, as well as genes known to be deregulated in different B cells malignancy, was altered by ?Np73? down-regulation. Together, these findings reveal a novel EBV mechanism that appears to play an important role in the transformation of primary B cells. PMID:23516355

Accardi, Rosita; Fathallah, Ikbal; Gruffat, Henri; Mariggio, Giuseppe; Le Calvez-Kelm, Florence; Voegele, Catherine; Bartosch, Birke; Hernandez-Vargas, Hector; McKay, James; Sylla, Bakary S.; Manet, Evelyne; Tommasino, Massimo

2013-01-01

110

Oncoprotein MDM2 is a ubiquitin ligase E3 for tumor suppressor p53  

Microsoft Academic Search

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

Reiko Honda; Hirofumi Tanaka; Hideyo Yasuda

1997-01-01

111

BCL6 Oncoprotein in Breast Cancer: Loss of Expression in Disease Progression  

Microsoft Academic Search

Objective: To investigate the biological role of BCL-6 oncoprotein in breast cancer disease progression (recurrence and metastasis). Methods: The series consisted of 93 consecutive female patients with primary breast cancer and median follow-up of 10 years. BCL-6 expression was assessed in vivo by immunohistochemistry and real-time PCR. Breast cancer cell lines and some metastasis-related genes (CXCR4, Itg?-3 and FLT-1) were

António E. Pinto; Saudade André; Giovani Silva; Sara Vieira; Ana C. Santos; Sérgio Dias; Jorge Soares

2009-01-01

112

A high-throughput assay for small molecule destabilizers of the KRAS oncoprotein.  

PubMed

Mutations in the Ras family of small GTPases, particularly KRAS, occur at high frequencies in cancer and represent a major unmet therapeutic need due to the lack of effective targeted therapies. Past efforts directed at inhibiting the activity of the Ras oncoprotein have proved difficult. We propose an alternative approach to target Ras by eliminating Ras protein from cells with pharmacological means. In this study, we developed a cell-based, high-content screening platform to identify small molecules that could promote the degradation of the KRAS oncoprotein. We generated an EGFP-KRASG12V fluorescence reporter system and implemented it for automated screening in 1536-well plates using high-throughput cellular imaging. We screened a library of clinically relevant compounds at wide dose range and identified Ponatinib and AMG-47a as two candidate compounds that selectively reduced the levels of EGFP-KRASG12V protein but did not affect EGFP protein in cells. This proof-of-principle study demonstrates that it is feasible to use a high-throughput screen to identify compounds that promote the degradation of the Ras oncoprotein as a new approach to target Ras. PMID:25093678

Carver, Joseph; Dexheimer, Thomas S; Hsu, Dennis; Weng, Meng-Tzu; Smith, Jordan L; Guha, Rajarshi; Jadhav, Ajit; Simeonov, Anton; Luo, Ji

2014-01-01

113

A novel peptide motif binding to and blocking the intracellular activity of the human papillomavirus E6 oncoprotein.  

PubMed

Specific types of human papillomaviruses (HPVs) cause cervical cancer. The viral E6 oncogene is a critical factor for maintaining the malignant phenotype of HPV-positive tumour cells. By yeast two-hybrid screening of a randomised peptide expression library, we isolated linear short peptides, which specifically bind to the HPV16 E6 oncoprotein. Sequence alignments and mutational analyses of the peptides identified a hitherto undiscovered E6-binding motif. Intracellular expression of a peptide containing the novel E6-binding motif resulted in inhibition of colony formation capacity, specifically of HPV16-positive cancer cells. A solubility-optimised variant of the peptide was created, which binds to HPV16 E6 with high affinity. Its intracellular expression efficiently induced apoptosis in HPV16-positive cancer cells. This was linked to restoration of intracellular p53 activities. Thus, this newly identified E6-binding motif could form a novel basis for the development of rational strategies for the treatment of HPV16-positive preneoplastic and neoplastic lesions. PMID:19099279

Dymalla, Susanne; Scheffner, Martin; Weber, Elvira; Sehr, Peter; Lohrey, Claudia; Hoppe-Seyler, Felix; Hoppe-Seyler, Karin

2009-03-01

114

Interaction of hepatitis B viral oncoprotein with cellular target HBXIP dysregulates centrosome dynamics and mitotic spindle formation.  

PubMed

Hepatitis B virus infection is associated with hepatocellular carcinoma, claiming 1 million lives annually worldwide. To understand the carcinogenic mechanism of hepatitis B virus-encoded oncoprotein HBx, we explored the function of HBx interaction with its cellular target HBXIP. Previously, we demonstrated that viral HBx and cellular HBXIP control mitotic spindle formation, regulating centrosome splitting. By using various fragments of HBx, we determined that residues (137)CRHK(140) within HBx are necessary for binding HBXIP. Mutation of the (137)CRHK(140) motif in HBx abolished its ability to bind HBXIP and to dysregulate centrosome dynamics in HeLa and immortal diploid RPE-1 cells. Unlike wild-type HBx, which targets to centrosomes as determined by subcellular fractionation and immunofluorescence microscopy, HBx mutants failed to localize to centrosomes. Overexpression of viral HBx wild-type protein and knockdown of endogenous HBXIP altered centrosome assembly and induced modifications of pericentrin and centrin-2, two essential proteins required for centrosome formation and function, whereas HBXIP nonbinding mutants of HBx did not. Overexpression of HBXIP or fragments of HBXIP that bind HBx neutralized the effects of viral HBx on centrosome dynamics and spindle formation. These results suggest that HBXIP is a critical target of viral HBx for promoting genetic instability through formation of defective spindles and subsequent aberrant chromosome segregation. PMID:18032378

Wen, Yunfei; Golubkov, Vladislav S; Strongin, Alex Y; Jiang, Wei; Reed, John C

2008-02-01

115

The Proto-oncoprotein Brx Activates Estrogen Receptor ? by a p38 Mitogen-activated Protein Kinase Pathway*  

PubMed Central

The estrogen receptors (ERs) are ligand-inducible transcription factors that play key roles in the control of growth and differentiation in reproductive tissues. We showed that the novel Dbl family proto-oncoprotein Brx enhances ligand-dependent activity of ER? via a Cdc42-dependent pathway. Brx also significantly enhances ligand-dependent activity of ER?. This enhancement is not affected by inhibition of p44/42 mitogen-activated protein kinase (MAPK) activation by PD98059. However, addition of the p38 MAPK inhibitor SB202190 abrogates the enhancement of ER? activity by Brx, showing that p38 MAPK activity is required for the enhancement of ER? function by Brx. In COS-7 cells, transfection of Brx leads to activation of endogenous p38 MAPK activity. Co-expression of the ?2 isoform of human p38 MAPK and a constitutively active form of the p38 MAPK kinase MKK6 (MKK6-EE) synergistically augments ligand-dependent activity of ER?. Our findings suggest that p38 MAPKs may be important regulators of ER? activity. PMID:11579095

Driggers, Paul H.; Segars, James H.; Rubino, Domenica M.

2014-01-01

116

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. PMID:20540776

2010-01-01

117

Substrate binding activates the designed triple mutant of the colicin E7 metallonuclease.  

PubMed

The nuclease domain of colicin E7 (NColE7) cleaves DNA nonspecifically. The active center is a Zn(2+)-containing HNH motif at the C-terminus. The N-terminal loop is essential for the catalytic activity providing opportunity for allosteric modulation of the enzyme. To identify the key residues responsible for the structural integrity of NColE7, a virtual alanine scan was performed on a semiempirical quantum chemical level within the 25 residue long N-terminal sequence (446-470). Based on the calculations the T454A/K458A/W464A-NColE7 triple mutant (TKW) was expressed and purified. According to the agarose gel electrophoresis experiments and linear dichroism spectra the catalytic activity of the TKW mutant decreased in comparison with wild-type NColE7. The distorted structure and weakened Zn(2+) binding may account for this as revealed by circular dichroism spectra, mass spectrometry, fluorescence-based thermal analysis and isothermal microcalorimetric titrations. Remarkably, the substrate induced the folding of the mutant protein. PMID:25156149

Németh, Eszter; Körtvélyesi, Tamás; Kožíšek, Milan; Thulstrup, Peter W; Christensen, Hans E M; Asaka, Masamitsu N; Nagata, Kyosuke; Gyurcsik, Béla

2014-12-01

118

C/EBP? or C/EBP? oncoproteins regulate the intrinsic and extrinsic apoptotic pathways by direct interaction with NF-?B p50 bound to the bcl-2 and FLIP gene promoters  

PubMed Central

CCAAT/enhancer binding protein ? (C/EBP?) is mutated in 10% of acute myeloid leukemias, resulting in either a truncated protein or an altered leucine zipper (C/EBP?LZ) that prevents DNA-binding. C/EBP? induces bcl-2 in cooperation with NF-?B p50 to inhibit apoptosis. We now demostrate that C/EBP? or a C/EBP?LZ oncoprotein bind the bcl-2 P2 promoter in chromatin immunoprecipitation assays and induce the promoter dependent on the integrity of a ?B site. C/EBP? expressed as a transgene in B cells binds and activates the bcl-2 promoter, but not in nfkb1?/? mice lacking NF-?B p50. Bcl-2 is central to the intrinsic apoptotic pathway, while FLICE inhibitory protein (FLIP) modulates caspase-8, the initiator caspase of the extrinsic pathway. C/EBP? and C/EBP?LZ also bind the FLIP promoter and induce its expression dependent upon NF-?B p50. Moreover, induction of FLIP by C/EBP? protects splenocytes from Fas ligand-induced apoptosis, but only if p50 is present. We also demonstrate direct interaction between bacterially produced C/EBP? and NF-?B p50, mediated by the C/EBP? basic region. These findings indicate that C/EBP? or its oncoproteins activate the bcl-2 and FLIP genes by tethering to their promoters via bound NF-?B p50. Targeting their interaction may favor apoptosis of transformed cells. PMID:18987666

Paz-Priel, I; Ghosal, AK; Kowalski, J; Friedman, AD

2008-01-01

119

Estrogen contributes to non-pRb targeted HPV18 E7-caused cell proliferation and transformation.  

PubMed

Almost all of cervical carcinoma arises as a result of persistent infection with high-risk human papillomaviruses (HPVs) where E7 oncogene plays an important role. In addition, estrogen is a confirmed cofactor in HPV related cervical carcinoma working synergistically with E7. There are two pathways involved in the E7 carcinogenesis of cervical cancer, the pRb-dependent and pRb-independent pathway. In this study we analyzed that whether estrogen contributes to high-risk HPV E7 in cervical carcinogenesis via pRb-independent pathway or not. E7(DeltaRB), which can not bind to and degrade pRb protein, hence no transformation ability, worked synergistically with estrogen in cell proliferation and transformation. Estrogen combined with PTD-HPV18E7(DeltaRB) enhanced cell proliferation rate, induced genomic instability, including abnormal centrosome duplication and chromosomal instability, and exhibited malignant transformation with anchorage-independent growth. We also observed that, PTD-HPV18E7(DeltaRB) can interact with c-Jun and c-Myc proteins, but this interaction was limited to the estrogen-treated cells where c-Jun and c-Myc were expressed highly and no such interaction was observed in estrogen-untreated cells where c-Jun and c-Myc expression levels were low. In conclusion, estrogen can cooperate with E7 through a pRB-independent manner in cervical carcinogenesis. The functional interaction between E7 and c-Jun or between E7 and c-Myc could only be triggered when the c-Jun or c-Myc expression level reaches a certain threshold. PMID:20009582

Yan, Xiaofei; Shah, Walayat; Li, Xu; Wang, Yili

2010-02-01

120

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. PMID:23708675

OH, JI-EUN; KIM, JEONG-OH; SHIN, JUNG-YOUNG; ZHANG, XIANG-HUA; WON, HYE-SUNG; CHUN, SANG-HOON; JUNG, CHAN-KWON; PARK, WON-SANG; NAM, SUK-WOO; EUN, JUNG-WOO; KANG, JIN-HYOUNG

2013-01-01

121

High incidence of female reproductive tract cancers in FA-deficient HPV16-transgenic mice correlates with E7's induction of DNA damage response, an activity mediated by E7's inactivation of pocket proteins.  

PubMed

Fanconi anemia (FA) is a rare genetic disorder caused by defects in a DNA damage repair system, the FA pathway. FA patients frequently develop squamous cell carcinoma (SCC) at sites that are associated with human papillomavirus (HPV)-driven cancer including the female reproductive tract. To assess experimentally whether FA deficiency increases susceptibility to HPV-associated cervical/vaginal cancer, we monitored cancer incidence in the female lower reproductive tract of FA-deficient mice expressing HPV16 oncogenes, E6 and/or E7. FA deficiency specifically increased the incidence of cancers in mice expressing E7; but this effect was not observed in mice just expressing E6. We also observed that E7, but not E6, induced DNA damage as scored by induction of ?-H2AX and 53BP1 (p53 binding protein 1) nuclear foci, and this induction was heightened in FA-deficient tissue. Finally, we discovered that this induction of DNA damage responses was recapitulated in mice deficient in expression of 'pocket' proteins, pRb, p107 and p130, which are established targets of E7. Our findings support the hypothesis that E7 induces cancer by causing DNA damage at least in part through the inactivation of pocket proteins. This hypothesis explains why a deficiency in DNA damage repair would increase susceptibility to E7-driven cancer. PMID:24013229

Park, J W; Shin, M-K; Lambert, P F

2014-06-26

122

The Human Papillomavirus E7 Proteins Associate with p190RhoGAP and Alter Its Function  

PubMed Central

ABSTRACT Using mass spectrometry, we identified p190RhoGAP (p190) as a binding partner of human papillomavirus 16 (HPV16) E7. p190 belongs to the GTPase activating protein (GAP) family and is one of the primary GAPs for RhoA. GAPs stimulate the intrinsic GTPase activity of the Rho proteins, leading to Rho inactivation and influencing numerous biological processes. RhoA is one of the best-characterized Rho proteins and is specifically involved in formation of focal adhesions and stress fibers, thereby regulating cell migration and cell spreading. Since this is the first report that E7 associates with p190, we carried out detailed interaction studies. We show that E7 proteins from other HPV types also bind p190. Furthermore, we found that conserved region 3 (CR3) of E7 and the middle domain of p190 are important for this interaction. More specifically, we identified two residues in CR3 of E7 that are necessary for p190 binding and used mutants of E7 with mutations of these residues to determine the biological consequences of the E7-p190 interaction. Our data suggest that the interaction of E7 with p190 dysregulates this GAP and alters the actin cytoskeleton. We also found that this interaction negatively regulates cell spreading on a fibronectin substrate and therefore likely contributes to important aspects of the HPV life cycle or HPV-induced tumorigenesis. IMPORTANCE This study identifies p190RhoGAP as a novel cellular binding partner for the human papillomavirus (HPV) E7 protein. Our study shows that a large number of different HPV E7 proteins bind p190RhoGAP, and it identifies regions in both E7 and p190RhoGAP which are important for the interaction to occur. This study also highlights the likelihood that the E7-p190RhoGAP interaction may have important biological consequences related to actin organization in the infected cell. These changes could be an important contributor to the viral life cycle and during progression to cancer in HPV-infected cells. Importantly, this work also emphasizes the need for further study in a field which has largely been unexplored as it relates to the HPV life cycle and HPV-induced transformation. PMID:24403595

Todorovic, Biljana; Nichols, Anthony C.; Chitilian, Jennifer M.; Myers, Michael P.; Shepherd, Trevor G.; Parsons, Sarah J.; Barrett, John W.; Banks, Lawrence

2014-01-01

123

A simultaneous flow cytometric assay for c-myc oncoprotein and DNA in nuclei from paraffin embedded material.  

PubMed

A simultaneous flow cytometric assay for the c-myc oncoprotein and DNA in nuclei extracted from archival paraffin wax embedded clinical biopsies is presented. The nuclei were extracted by pepsin digestion after dewaxing 20 micron sections. The c-myc oncoprotein was probed with a mouse monoclonal antibody. This was raised against a synthetic peptide corresponding to a hydrophilic region of the protein predicted from the amino acid sequence. The technique is illustrated with biopsies from patients with testicular cancer and with benign and malignant neoplasms of the colon. PMID:3902971

Watson, J V; Sikora, K; Evan, G I

1985-10-24

124

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

PubMed Central

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

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

2013-01-01

125

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

PubMed Central

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

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

2014-01-01

126

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

PubMed

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

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

2014-01-01

127

The TrkAIII Oncoprotein Inhibits Mitochondrial Free Radical ROS-Induced Death of SH-SY5Y Neuroblastoma Cells by Augmenting SOD2 Expression and Activity at the Mitochondria, within the Context of a Tumour Stem Cell-like Phenotype  

PubMed Central

The developmental and stress-regulated alternative TrkAIII splice variant of the NGF receptor TrkA is expressed by advanced stage human neuroblastomas (NBs), correlates with worse outcome in high TrkA expressing unfavourable tumours and exhibits oncogenic activity in NB models. In the present study, we report that constitutive TrkAIII expression in human SH-SY5Y NB cells inhibits Rotenone, Paraquat and LY83583-induced mitochondrial free radical reactive oxygen species (ROS)-mediated death by stimulating SOD2 expression, increasing mitochondrial SOD2 activity and attenuating mitochondrial free radical ROS production, in association with increased mitochondrial capacity to produce H2O2, within the context of a more tumour stem cell-like phenotype. This effect can be reversed by the specific TrkA tyrosine kinase inhibitor GW441756, by the multi-kinase TrkA inhibitors K252a, CEP-701 and Gö6976, which inhibit SOD2 expression, and by siRNA knockdown of SOD2 expression, which restores the sensitivity of TrkAIII expressing SH-SY5Y cells to Rotenone, Paraquat and LY83583-induced mitochondrial free radical ROS production and ROS-mediated death. The data implicate the novel TrkAIII/SOD2 axis in promoting NB resistance to mitochondrial free radical-mediated death and staminality, and suggest that the combined use of TrkAIII and/or SOD2 inhibitors together with agents that induce mitochondrial free radical ROS-mediated death could provide a therapeutic advantage that may also target the stem cell niche in high TrkA expressing unfavourable NB. PMID:24736663

Di Ianni, Natalia; Cappabianca, Lucia; Ragone, Marzia; Ianni, Giulia; Gulino, Alberto; Mackay, Andrew R.

2014-01-01

128

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

E-print Network

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

Paris-Sud XI, Université de

129

Supersymmetric E7(7) exceptional field theory  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

130

Abrogation of growth arrest signals by human papillomavirus type 16 E7 is mediated by sequences required for transformation.  

PubMed Central

Cells arrest in the G1 or G0 phase of the cell cycle in response to a variety of negative growth signals that induce arrest by different molecular pathways. The ability of human papillomavirus (HPV) oncogenes to bypass these signals and allow cells to progress into the S phase probably contributes to the neoplastic potential of the virus. The E7 protein of HPV-16 was able to disrupt the response of epithelial cells to three different negative growth arrest signals: quiescence imposed upon suprabasal epithelial cells, G1 arrest induced by DNA damage, and inhibition of DNA synthesis caused by treatment with transforming growth factor beta. The same set of mutated E7 proteins was able to abrogate all three growth arrest signals. Mutant proteins that failed to abrogate growth arrest signals were transformation deficient and included E7 proteins that bound retinoblastoma protein in vitro. In contrast, HPV-16 E6 was able to bypass only DNA damage-induced G1 arrest, not suprabasal quiescence or transforming growth factor beta-induced arrest. The E6 and E7 proteins from the low-risk virus HPV-6 were not able to bypass any of the growth arrest signals. PMID:8794328

Demers, G W; Espling, E; Harry, J B; Etscheid, B G; Galloway, D A

1996-01-01

131

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

PubMed

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

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

2014-01-01

132

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

PubMed Central

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

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

2014-01-01

133

Oncoprotein kinase  

DOEpatents

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

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

2001-02-27

134

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. PMID:20569464

2010-01-01

135

Bcl2 Oncoprotein Expression Is Increased Especially in the Portion of Small Cell Carcinoma within the Combined Type of Small Cell Lung Cancer  

Microsoft Academic Search

Immunohistochemical analysis of Bcl-2 oncoprotein, one of the oncogenes associated with the regulation of programmed cell death, was performed on 12 surgically resected tumors of the combined type of small-cell lung cancer. Ten cases (83%) expressed Bcl-2 oncoprotein within the tumor tissues. Two of them showed its expression in both the small cell carcinoma and non-small cell carcinoma types, and

Masahiko Higashiyama; Osamu Doi; Ken Kodama; Hideoki Yokouchi; Ryuhei Tateishi

1996-01-01

136

The clinical significance between activation of nuclear factor kappa B transcription factor and overexpression of HER2\\/neu oncoprotein in Taiwanese patients with breast cancer  

Microsoft Academic Search

Background: This study investigated the role of nuclear factor-kappa B (NF-?B) activity in human breast cancer with overexpression of HER-2\\/neu oncoprotein, as well as its role on expression of different histological grades of cancer cells taken from Taiwanese breast cancer patients. Materials and methods: Specimens were collected from 82 female breast cancer patients. The HER-2\\/neu oncoprotein was measured by immunohistochemistry.

Ming-Feng Hou; Shwu-Bin Lin; Shyng-Shiou F. Yuan; Shih-Meng Tsai; Szu-Hua Wu; Fu Ou-Yang; Jan-Shih Hsieh; Kun-Bow Tsai; Tsung-Jen Huang; Li-Yu Tsai

2003-01-01

137

Downstream and Intermediate Interactions of Synovial Sarcoma-Associated Fusion Oncoproteins and Their Implication for Targeted Therapy  

PubMed Central

Synovial sarcoma (SS), an aggressive type of soft tissue tumor, occurs mostly in adolescents and young adults. The origin and molecular mechanism of the development of SS remain only partially known. Over 90% of SS cases are characterized by the t(X;18)(p11.2;q11.2) translocation, which results mainly in the formation of SS18-SSX1 or SS18-SSX2 fusion genes. In recent years, several reports describing direct and indirect interactions of SS18-SSX1/SSX2 oncoproteins have been published. These reports suggest that the fusion proteins particularly affect the cell growth, cell proliferation, TP53 pathway, and chromatin remodeling mechanisms, contributing to SS oncogenesis. Additional research efforts are required to fully explore the protein-protein interactions of SS18-SSX oncoproteins and the pathways that are regulated by these partnerships for the development of effective targeted therapy. PMID:22550415

Przybyl, Joanna; Jurkowska, Monika; Rutkowski, Piotr; Debiec-Rychter, Maria; Siedlecki, Janusz A.

2012-01-01

138

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

139

Kaposi sarcoma herpesvirus (KSHV) vFLIP oncoprotein induces B cell transdifferentiation and tumorigenesis in mice  

PubMed Central

Kaposi sarcoma herpesvirus (KSHV) is specifically associated with Kaposi sarcoma (KS) and 2 B cell lymphoproliferative diseases, namely primary effusion lymphoma (PEL) and multicentric Castleman disease (MCD). KS, PEL, and MCD are largely incurable and poorly understood diseases most common in HIV-infected individuals. Here, we have revealed the role of viral FLICE-inhibitory protein (vFLIP) in the initiation of PEL and MCD by specifically expressing vFLIP at different stages of B cell differentiation in vivo. Mice showed MCD-like abnormalities and immunological defects including lack of germinal centers (GCs), impaired Ig class switching, and affinity maturation. In addition, they showed increased numbers of cells expressing cytoplasmic IgM-?, a thus far enigmatic feature of the KSHV-infected cells in MCD. B cell–derived tumors arose at high incidence and displayed Ig gene rearrangement with downregulated expression of B cell–associated antigens, which are features of PEL. Interestingly, these tumors exhibited characteristics of transdifferentiation and acquired expression of histiocytic/dendritic cell markers. These results define immunological functions for vFLIP in vivo and reveal what we believe to be a novel viral-mediated tumorigenic mechanism involving B cell reprogramming. Additionally, the robust recapitulation of KSHV-associated diseases in mice provides a model to test inhibitors of vFLIP as potential anticancer agents. PMID:21339646

Ballon, Gianna; Chen, Kang; Perez, Rocio; Tam, Wayne; Cesarman, Ethel

2011-01-01

140

A novel therapeutic fusion protein vaccine by two different families of heat shock proteins linked with HPV16 E7 generates potent antitumor immunity and antiangiogenesis.  

PubMed

Human papillomaviruses (HPV), particularly HPV16, is considered a necessary cause of cervical and oral cancer. Thus, the development of a therapeutic vaccine against HPV is important for the control of cervical cancer. However, therapeutic vaccination has been limited by inadequate antigen-specific immune responses. Heat shock proteins (HSP), including calreticulin (CRT), HSP70 and gp96, have been shown to act as potent immunoadjuvant to enhance antigen-specific tumor immunity. Previous studies have shown that N domain CRT (NCRT) or C-terminal half of HSP70 (hsp) linked with HPV16 E7 are capable of inducing potent antigen-specific CTL activity in experimental animal models. Here we developed a recombinant NCRT/E7/hsp fusion protein to investigate the synergistic effects of NCRT and hsp for enhancing the potency of HPV16 E7 therapeutic vaccine and evaluated the immune responses induced by this fusion protein. Our results demonstrated that NCRT and hsp synergistically exhibited significant increases in E7-specific CD8(+) T cell responses and impressive antitumor effects against E7-expressing tumors. Furthermore, the NCRT/E7/hsp fusion protein also generates potent antiangiogenic effects. These results indicate that NCRT/E7/hsp fusion protein is a promising therapeutic vaccine for treatment of cervical cancer through a combination of antigen-specific immunotherapy and antiangiogenesis, with possible therapeutic potential in clinical settings. PMID:18272260

Liu, Bo; Ye, Dongxia; Song, Xinxin; Zhao, Xinhua; Yi, Linan; Song, Jietao; Zhang, Zhiyuan; Zhao, Qingzheng

2008-03-01

141

Structure-Function Studies of the BTB\\/POZ Transcriptional Repression Domain from the Promyelocytic Leukemia Zinc Finger Oncoprotein1  

Microsoft Academic Search

The evolutionarily conserved BTB\\/POZ domain from the promyelo- cytic leukemia zinc finger (PLZF) oncoprotein mediates transcriptional repression through the recruitment of corepressor proteins containing histone deacetylases in acute promyelocytic leukemia. We have deter- mined the 2.0 Ĺ crystal structure of the BTB\\/POZ domain from PLZF (PLZF-BTB\\/POZ), and have carried out biochemical analysis of PLZF- BTB\\/POZ harboring site-directed mutations to probe

Xinmin Li; Hongzhuang Peng; David C. Schultz; Jesus M. Lopez-Guisa; Frank J. Rauscher; Ronen Marmorstein

1999-01-01

142

The ENTPD5/mt-PCPH oncoprotein is a catalytically inactive member of the ectonucleoside triphosphate diphosphohydrolase family  

PubMed Central

Expression of the ENTPD5/mt-PCPH onco-protein and overexpression of the normal ENTPD5/PCPH protein contribute to the malignant transformation of diverse mammalian cell types, and PCPH is mutated and/or deregulated in various human tumor types. Expression of PCPH or mt-PCPH caused similar phenotypes, yet the effects promoted by mt-PCPH expression were consistently and substantially greater. ATP depletion and increased stress-resistance are phenotypes commonly associated with PCPH and mt-PCPH expression. It was suggested that the intrinsic nucleoside triphosphate diphosphohydrolase (NTPDase) activity of PCPH and mt-PCPH may be responsible for these phenotypes, but direct supporting evidence remains to be established. Results from experiments designed to test such hypothesis demonstrate that, as expected, mt-PCPH expression in human colorectal carcinoma (CRC) cells decreased their ATP levels and conferred resistance to oxaliplatin, a colorectal cancer-relevant chemotherapeutic agent. Using a combination of site-directed mutagenesis, immunoprecipitation methods, in vitro enzyme activity assays and in situ enzyme activity determinations in live cells, this report also demonstrates that the mt-PCPH oncoprotein lacks detectable NTPDase activity, indicating that direct ATP cleavage by mt-PCPH did not cause the ATP depletion observed in mt-PCPH-expressing CRC cells. These results strongly suggest that the mt-PCPH oncoprotein may regulate the cellular energy levels and subsequent chemoresistance by an NTPDase-independent mechanism. Understanding possible alternative mechanisms will be essential to devise strategies for the successful treatment of predictably therapeutically resistant tumors expressing either increased PCPH levels or, particularly, the mt-PCPH oncoprotein. PMID:23921441

MacCARTHY, CAITLIN M.; NOTARIO, VICENTE

143

The ENTPD5/mt-PCPH oncoprotein is a catalytically inactive member of the ectonucleoside triphosphate diphosphohydrolase family.  

PubMed

Expression of the ENTPD5/mt-PCPH onco-protein and overexpression of the normal ENTPD5/PCPH protein contribute to the malignant transformation of diverse mammalian cell types, and PCPH is mutated and/or deregulated in various human tumor types. Expression of PCPH or mt-PCPH caused similar phenotypes, yet the effects promoted by mt-PCPH expression were consistently and substantially greater. ATP depletion and increased stress?resistance are phenotypes commonly associated with PCPH and mt-PCPH expression. It was suggested that the intrinsic nucleoside triphosphate diphosphohydrolase (NTPDase) activity of PCPH and mt-PCPH may be responsible for these phenotypes, but direct supporting evidence remains to be established. Results from experiments designed to test such hypothesis demonstrate that, as expected, mt-PCPH expression in human colorectal carcinoma (CRC) cells decreased their ATP levels and conferred resistance to oxaliplatin, a colorectal cancer-relevant chemotherapeutic agent. Using a combination of site-directed mutagenesis, immunoprecipitation methods, in vitro enzyme activity assays and in situ enzyme activity determinations in live cells, this report also demonstrates that the mt-PCPH oncoprotein lacks detectable NTPDase activity, indicating that direct ATP cleavage by mt-PCPH did not cause the ATP depletion observed in mt-PCPH-expressing CRC cells. These results strongly suggest that the mt-PCPH oncoprotein may regulate the cellular energy levels and subsequent chemoresistance by an NTPDase-independent mechanism. Understanding possible alternative mechanisms will be essential to devise strategies for the successful treatment of predictably therapeutically resistant tumors expressing either increased PCPH levels or, particularly, the mt-PCPH oncoprotein. PMID:23921441

MacCarthy, Caitlin M; Notario, Vicente

2013-10-01

144

Ribosomal Protein L11 Negatively Regulates Oncoprotein MDM2 and Mediates a p53Dependent Ribosomal-Stress Checkpoint Pathway  

Microsoft Academic Search

The gene encoding p53 mediates a major tumor suppression pathway that is frequently altered in human cancers. p53 function is kept at a low level during normal cell growth and is activated in response to various cellular stresses. The MDM2 oncoprotein plays a key role in negatively regulating p53 activity by either direct repression of p53 transactivation activity in the

Yanping Zhang; G. W. Wolf; Krishna Bhat; Aiwen Jin; Theresa Allio; William A. Burkhart; Yue Xiong

2003-01-01

145

c-erbB-2 oncoprotein is not an independent prognostic parameter in primary breast carcinoma. An immunohistochemical study.  

PubMed

The prognostic significance of c-erbB-2 oncoprotein expression was studied using the monoclonal antibody, anti-c-erbB-2 (CB-11, BioGenex) and the avidin-biotin-complex (ABC) technique. Four hundred and ninety patients with primary breast carcinoma diagnosed at Gentofte Hospital in the period 1980-1985 were included. Information about treatment, relapse-free period and overall survival was obtained from the Danish Breast Cancer Co-operative Group (DBCG). The mean follow-up period was more than 10 years. Fifteen per cent of the tumours showed positive immunoreactivity for c-erbB-2. Oncoprotein expression was correlated with presence of lymph node metastases, type of tumour, high number of mitoses, severe nuclear pleomorphism, high histological grade (poor differentiation), and absence of steroid hormone receptors. By univariate analysis, expression of c-erbB-2 oncoprotein, was correlated with poorer overall survival and shorter disease-free period in the entire cohort and in patients with lymph metastases, but not in the group of patients without lymph node metastases. By multivariate analysis, c-erbB-2 failed to be an independent prognostic marker for either disease-free period or overall survival, whereas classical histopathological parameters such as presence of lymph node metastases, high number of mitoses, high histological grade (poor differentiation) and absence of progesterone receptors turned out to be of independent prognostic significance. PMID:7946263

Haerslev, T; Jacobsen, G K

1994-08-01

146

FTS (fused toes homolog) a novel oncoprotein involved in uterine cervical carcinogenesis and a potential diagnostic marker for cervical cancer.  

PubMed

The high incidence and fatality rate of uterine cervical cancer warrant effective diagnostic and therapeutic target identification for this disease. Here, we have found a novel oncoprotein FTS (Fused Toes Homolog), which is involved in cervical cancer pathogenesis. Immunohistochemical analysis of human cervical biopsy samples revealed that the expression of FTS is absent in normal cervical epithelium but progressively overexpressed in human cervical intraneoplastic lesions (CIN-I to CIN-III), this characteristic phenomenon put this protein, a potential diagnostic marker for the screening of early neoplastic changes of cervix. Using FTS-specific small hairpin RNA (shRNA) in cervical cancer cells, we determined a specific role for FTS protein in, cervical neoplasia. Targeted stable knock down of FTS in HeLa cells led to the growth inhibition, cell-cycle arrest, and apoptosis with concurrent increase in p21 protein. FTS effectively represses the p21 mRNA expression in dual luciferase assay which indicates that p21 is transcriptionally regulated by this oncoprotein which in turn affect the regular cell-cycle process and its components. Consistent with this we found a reciprocal association between these proteins in early cervical neoplastic tissues. These data unraveled the involvement of new oncoprotein FTS in cervical cancer which plays a central role in carcinogenesis. Targeted inhibition of FTS lead to the shutdown of key elemental characteristics of cervical cancer and could lead to an effective therapeutic strategy for cervical cancer. PMID:20945372

Cinghu, Senthilkumar; Anandharaj, Arunkumar; Lee, Ho-chang; Yu, Jae-Ran; Park, Woo-Yoon

2011-06-01

147

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. PMID:22544745

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

2012-01-01

148

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

PubMed Central

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

Oteiza, Alexandra; Mechti, Nadir

2011-01-01

149

Reversible repression of papillomavirus oncogene expression in cervical carcinoma cells: consequences for the phenotype and E6-p53 and E7-pRB interactions.  

PubMed Central

The transforming genes E6 and E7 of high-risk human papillomaviruses are consistently expressed in papillomavirus-associated neoplasms of the anogenital tract. In papillomavirus type 18-associated SW 756 cervical carcinoma cells, transcription of the viral E6-E7 genes is blocked by dexamethasone. Herein we show that dexamethasone-mediated repression of the E6-E7 genes results in loss of the neoplastic phenotype of SW 756 cells. Withdrawal of dexamethasone restores E6-E7 expression and neoplastic growth. Moreover, reconstitution of E6-E7 gene expression by a dexamethasone-inducible expression vector renders the neoplastic phenotype resistant to dexamethasone. These results clearly indicate that the continuous expression of the viral E6-E7 oncogenes is required to maintain the neoplastic growth properties of SW 756 cervical cancer cells. The viral E6 protein destabilizes the p53 tumor suppressor gene product in vitro. Since low levels of p53 have been observed in papillomavirus-transformed keratinocyte cell lines, it was speculated that degradation of p53 by E6 contributes to papillomavirus-associated growth deregulation. Consistent with this hypothesis, we detected a significant increase in p53 levels upon dexamethasone-induced repression of papillomavirus E6-E7 oncogene expression. No p53 increase was observed in dexamethasone-treated cells in which the viral oncogene expression was restored. The viral E7 protein has been shown to complex with the retinoblastoma tumor suppressor gene product (pRB). In some cells, this interaction has been shown shown to release the transcription factor E2F from its complex with pRB, and it has been hypothesized that E7-induced, increased levels of free E2F contribute to the transforming potential of the viral oncogenes. In gel shift experiments, we detected relatively stable complexes of pRB and E2F in all SW 756-derived cells, independent of the level of E7 expression. This suggests that E7-mediated release of E2F from its complex with pRB might not be required to maintain the neoplastic phenotype of human papillomavirus-associated cancer cells, although a possibly relevant partial E7-mediated release of E2F from pRB cannot be excluded. Images PMID:8151752

von Knebel Doeberitz, M; Rittmuller, C; Aengeneyndt, F; Jansen-Durr, P; Spitkovsky, D

1994-01-01

150

The Oncoprotein BCL11A Binds to Orphan Nuclear Receptor TLX and Potentiates its Transrepressive Function  

PubMed Central

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.; Buzon, Victor; Carbo, Laia R.; Schorova, Lenka; Luders, Jens; Estebanez-Perpina, Eva

2012-01-01

151

Adenovirus E1B 55-Kilodalton Oncoprotein Inhibits p53 Acetylation by PCAF  

PubMed Central

The adenovirus E1B 55-kDa protein binds to cellular tumor suppressor p53 and inactivates its transcriptional transactivation function. p53 transactivation activity is dependent upon its ability to bind to specific DNA sequences near the promoters of its target genes. It was shown recently that p53 is acetylated by transcriptional coactivators p300, CREB bidning protein (CBP), and PCAF and that acetylation of p53 by these proteins enhances p53 sequence-specific DNA binding. Here we show that the E1B 55-kDa protein specifically inhibits p53 acetylation by PCAF in vivo and in vitro, while acetylation of histones and PCAF autoacetylation is not affected. Furthermore, the DNA-binding activity of p53 is diminished in cells expressing the E1B 55-kDa protein. PCAF binds to the E1B 55-kDa protein and to a region near the C terminus of p53 encompassing Lys-320, the specific PCAF acetylation site. We further show that the E1B 55-kDa protein interferes with the physical interaction between PCAF and p53, suggesting that the E1B 55-kDa protein inhibits PCAF acetylase function on p53 by preventing enzyme-substrate interaction. These results underscore the importance of p53 acetylation for its function and suggest that inhibition of p53 acetylation by viral oncoproteins prevent its activation, thereby contributing to viral transformation. PMID:10891493

Liu, Yue; Colosimo, April L.; Yang, Xiang-Jiao; Liao, Daiqing

2000-01-01

152

Structural characterization of a C-terminally truncated E5 oncoprotein from papillomavirus in lipid bilayers.  

PubMed

Abstract E5 is the major transforming oncoprotein of bovine papillomavirus, which activates the platelet-derived growth factor receptor ? in a highly specific manner. The short transmembrane protein E5 with only 44 residues interacts directly with the transmembrane segments of the receptor, but structural details are not available. Biophysical investigations are challenging, because the hydrophobic E5 protein tends to aggregate and get cross-linked non-specifically via two Cys residues near its C-terminus. Here, we demonstrate that a truncation by 10 amino acids creates a more manageable protein that can be conveniently used for structure analysis. Synchrotron radiation circular dichroism and solid-state 15N- and 31P-nuclear magnetic resonance spectroscopy show that this E5 variant serves as a representative model for the wild-type protein. The helical conformation of the transmembrane segment, its orientation in the lipid bilayer, and the ability to form homodimers in the membrane are not affected by the C-terminal truncation. PMID:25324446

Windisch, Dirk; Ziegler, Colin; Bürck, Jochen; Ulrich, Anne S

2014-12-01

153

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

154

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

Code of Federal Regulations, 2012 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...

2012-10-01

155

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

Code of Federal Regulations, 2013 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...

2013-10-01

156

Characterization of the specific cleavage of ceiE7-mRNA of the bactericidal ColE7 operon.  

PubMed

Posttranscriptional control of the bactericidal ColE7 operon has been implicated by a feedback endonucleolytic cleavage of its own mRNA. The cleavage site has been located at the coding region of ceiE7, the second cistron of the ColE7 cea-cei-cel polycistronic transcript. Interestingly, Im7 protein, the translation product of ceiE7, is required for the specific cleavage. It was found that both sequence (GAUCUGAUU) flanking the cleavage site and the putative T1 stem-loop structure distal to the coding region of ceiE7 gene play a critical role for the specific cleavage of ceiE7-mRNA. Furthermore, we have verified that a di-nucleotide GG sequence located at the topmost position of the loop region of the putative stem-loop structure is essential for the specific cleavage of ceiE7-mRNA. Thus, our data reveal the existence of a novel mRNA degradative machinery for the regulation of the expression of ColE7 operon. PMID:12459183

Chang, Ssu-Jean; Hsieh, Shih-Yang; Yuan, Hanna S; Chak, Kin-Fu

2002-12-13

157

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

PubMed Central

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

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

2012-01-01

158

Emerging Concepts in the Analysis of Transcriptional Targets of the MYC Oncoprotein: Are the Targets Targetable?  

PubMed

Activation of the MYC oncoprotein is among the most ubiquitous events in human cancer. MYC functions in part as a sequence-specific regulator of transcription. Although early searches for direct downstream target genes that explain MYC's potent biological activity were met with enthusiasm, the postgenomic decade has brought the realization that MYC regulates the transcription of not just a manageably small handful of target genes but instead up to 15% of all active loci. As the dust has begun to settle, two important concepts have emerged that reignite hope that understanding MYC's downstream targets might still prove valuable for defining critical nodes for therapeutic intervention in cancer patients. First, it is now clear that MYC target genes are not a random sampling of the cellular transcriptome but instead fall into specific, critical biochemical pathways such as metabolism, chromatin structure, and protein translation. In retrospect, we should not have been surprised to discover that MYC rewires cell physiology in a manner designed to provide the tumor cell with greater biosynthetic properties. However, the specific details that have emerged from these studies are likely to guide the development of new clinical tools and strategies. This raises the second concept that instills renewed optimism regarding MYC target genes. It is now clear that not all MYC target genes are of equal functional relevance. Thus, it may be possible to discern, from among the thousands of potential MYC target genes, those whose inhibition will truly debilitate the tumor cell. In short, targeting the targets may ultimately be a realistic approach after all. PMID:21533016

Van Dang, Chi; McMahon, Steven B

2010-06-01

159

High expression of oncoprotein DEK predicts poor prognosis of small cell lung cancer  

PubMed Central

Oncoprotein DEK plays an important role in cancer tumorigenesis. To explore the clinical implication of DEK expression on prognostic evaluation in small cell lung cancer (SCLC), 130 cases of SCLC with strict follow-up were selected for immunohistochemical (IHC) staining of DEK protein. The correlation between DEK expression and clinicopathological features of SCLC was evaluated using the Chi-square and Fisher’s exact tests, survival rates were calculated using the Kaplan-Meier method and univariate and multivariate analyses were performed using the Cox proportional hazards regression model. IHC analysis demonstrated that DEK protein staining was strongly positive and significantly higher (44.62%) in SCLC compared with either adjacent non-tumor or normal lung tissues (P < 0.001 for both). DEK expression correlated with large tumor size (P = 0.025) and late pathologic stage (P = 0.005). Moreover, it correlated with low disease-free (P = 0.004) and 5-year (P = 0.005) survival rates. In the late-stage group, disease-free and 5-year survival rates of patients with high level DEK expression were significantly lower than those with low level DEK expression (P = 0.006 and P = 0.001, respectively). Furthermore, Cox analysis revealed that DEK expression emerged as a significant independent hazard factor for the overall survival rate of patients with SCLC (HR: 1.594, 95% CI: 1.087-2.336, P = 0.017). In conclusion, DEK plays an important role in the progression of SCLC. DEK may potentially be used as an independent biomarker for the prognostic evaluation of SCLC.

Wang, Xiaoyan; Lin, Lijuan; Ren, Xiangshan; Lin, Zhenhua; Li, Zhuhu; Li, Chunyu; Jin, Tiefeng

2014-01-01

160

The Human DEK Proto-Oncogene Is a Senescence Inhibitor and an Upregulated Target of High-Risk Human Papillomavirus E7  

PubMed Central

The human DEK proto-oncogene is a nucleic acid binding protein with suspected roles in human carcinogenesis, autoimmune disease, and viral infection. Intracellular DEK functions, however, are poorly understood. In papillomavirus-positive cervical cancer cells, downregulation of viral E6/E7 oncogene expression results in cellular senescence. We report here the specific repression of DEK message and protein levels in senescing human papillomavirus type 16- (HPV16-) and HPV18-positive cancer cell lines as well as in primary cells undergoing replicative senescence. Cervical cancer cell senescence was partially overcome by DEK overexpression, and DEK overexpression was sufficient for extending the life span of primary keratinocytes, supporting critical roles for this molecule as a senescence regulator. In order to determine whether DEK is a bona fide HPV oncogene target in primary cells, DEK expression was monitored in human keratinocytes transduced with HPV E6 and/or E7. The results identify high-risk HPV E7 as a positive DEK regulator, an activity that is not shared by low-risk HPV E7 protein. Experiments in mouse embryo fibroblasts recapitulated the observed E7-mediated DEK induction and demonstrated that both basal and E7-induced regulation of DEK expression are controlled by the retinoblastoma protein family. Taken together, our results suggest that DEK upregulation may be a common event in human carcinogenesis and may reflect its senescence inhibitory function. PMID:16254365

Wise-Draper, Trisha M.; Allen, Hillary V.; Thobe, Megan N.; Jones, Elizabeth E.; Habash, Kristen B.; Munger, Karl; Wells, Susanne I.

2005-01-01

161

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. PMID:22792175

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

2012-01-01

162

MIR125B1 represses the degradation of the PML-RARA oncoprotein by an autophagy-lysosomal pathway in acute promyelocytic leukemia.  

PubMed

Acute promyelocytic leukemia (APL) is characterized by the t(15;17)-associated PML-RARA fusion gene. We have previously found that MIR125B1 is highly expressed in patients with APL and may be associated with disease pathogenesis; however, the mechanism by which MIR125B1 exerts its oncogenic potential has not been fully elucidated. Here, we demonstrated that MIR125B1 abundance correlates with the PML-RARA status. MIR125B1 overexpression enhanced PML-RARA expression and inhibited the ATRA-induced degradation of the PML-RARA oncoprotein. RNA-seq analysis revealed a direct link between the PML-RARA degradation pathway and MIR125B1-arrested differentiation. We further demonstrated that the MIR125B1-mediated blockade of PML-RARA proteolysis was regulated via an autophagy-lysosomal pathway, contributing to the inhibition of APL differentiation. Furthermore, we identified DRAM2 (DNA-damage regulated autophagy modulator 2), a critical regulator of autophagy, as a novel target that was at least partly responsible for the function of MIR125B1 involved in autophagy. Importantly, the knockdown phenotypes for DRAM2 are similar to the effects of overexpressing MIR125B1 as impairment of PML-RARA degradation, inhibition of autophagy, and myeloid cell differentiation arrest. These effects of MIR125B1 and its target DRAM2 were further confirmed in an APL mouse model. Thus, MIR125B1 dysregulation may interfere with the effectiveness of ATRA-mediated differentiation through an autophagy-dependent pathway, representing a novel potential APL therapeutic target. PMID:25126724

Zeng, Cheng-Wu; Chen, Zhen-Hua; Zhang, Xing-Ju; Han, Bo-Wei; Lin, Kang-Yu; Li, Xiao-Juan; Wei, Pan-Pan; Zhang, Hua; Li, Yangqiu; Chen, Yue-Qin

2014-10-01

163

Epstein-Barr Virus Downregulates MicroRNA 203 through the Oncoprotein Latent Membrane Protein 1: a Contribution to Increased Tumor Incidence in Epithelial Cells  

PubMed Central

The Epstein-Barr virus (EBV) is highly associated with nasopharyngeal carcinoma (NPC), and it regulates some microRNAs (miRNAs) that are involved in the development of cancer. The role of EBV in the deregulation of cellular miRNAs and how this affects the progression of NPC remain to be investigated. An analysis of the miRNA profile in an EBV-infected cell line revealed that miRNA 203 (miR-203) was downregulated. miR-203 is expressed specifically in epithelial cells. This downregulation of miR-203 was further verified and functionally analyzed. miR-203 was downregulated substantially in epithelial cells and NPC tissues that were latently infected with EBV. Downregulation of miR-203 also occurred during the early stage of EBV infection. Furthermore, the viral oncoprotein, latent membrane protein 1 (LMP1), was responsible for downregulation of miR-203. Removal of the latent EBV genome or suppression of LMP1 resulted in restoration of miR-203 expression. EBV-LMP1 mediated the downregulation of miR-203 at the primary transcript level. E2F3 and CCNG1 were identified as target genes of miR-203. Ectopic expression of miR-203 inhibited EBV-induced S-phase entry and transformation in vivo. Overexpression of the targets overcame the effects of miR-203 mimics on the cell cycle, and the expression of target genes in tumor models was inhibited by miR-203. Inhibitors of Jun N-terminal protein kinase (JNK) and NF-?B blocked miR-203 downregulation. These results imply that EBV promotes malignancy by downregulating cellular miR-203, which contributes to the etiology of NPC. PMID:22205737

Yu, Haibo; Zuo, Lielian; Yan, Qijia; Yu, Zhengyuan; Li, Xiayu; Huang, Jin; Zhao, Lian; Tang, Hailin; Luo, Zhaohui; Liao, Qianjin; Zeng, Zhaoyang; Zhang, Junyi

2012-01-01

164

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

PubMed Central

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

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

2014-01-01

165

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

PubMed Central

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

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

2013-01-01

166

Targeting SET/I2PP2A Oncoprotein Functions as a Multi-pathway Strategy for Cancer Therapy  

PubMed Central

The SET oncoprotein participates in cancer progression by affecting multiple cellular processes, inhibiting the tumor suppressor PP2A and inhibiting the metastasis suppressor nm23-H1. Based upon these multiple activities, we hypothesized that targeted inhibition of SET would have multiple discrete and measurable effects on cancer cells. Here, the effects of inhibiting SET oncoprotein function on intracellular signaling and proliferation of human cancer cell lines was investigated. We observed the effects of COG112, a novel SET interacting peptide, on PP2A activity, Akt signaling, nm23-H1 activity, and cellular migration/invasion in human U87 glioblastoma and MDA-MB-231 breast adenocarcinoma cancer cell lines. We found that COG112 interacted with SET protein and inhibited the association between SET and PP2A-c or nm23-H1. The interaction between COG112 and SET caused PP2A phosphatase, and nm23-H1 exonuclease activities, to increase. COG112-mediated increases in PP2A activity resulted in the inhibition of Akt signaling and cellular proliferation. Additionally, COG112 inhibited SET association with Rac1 leading to decreased cellular migration and invasion. COG112 treatment releases the SET-mediated inhibition of the tumor suppressor PP2A, as well as the metastasis suppressor nm23-H1. These results establish SET as a novel molecular target, and that the inhibition of SET may have beneficial effects in cancer chemotherapy. PMID:21297667

Switzer, Christopher H.; Cheng, Robert Y.S.; Vitek, Timothy M.; Christensen, Dale J.; Wink, David A.; Vitek, Michael P.

2010-01-01

167

Prevention and Inhibition of TC-1 Cell Growth in Tumor Bearing Mice by HPV16 E7 Protein in Fusion with Shiga Toxin B-Subunit from shigella dysenteriae  

PubMed Central

Objective: For immunotherapy of human papillomavirus (HPV) -16-associated cervical cancers the E7 protein is considered a prime candidate. However it is a poor inducer of cytotoxic T-cell response, when being used as a singular antigen in protein vaccination. Hence, in this study we focused on the utilization of a vaccine delivery system for prevention or treatment of cervical cancer. Materials and Methods: In this experimental study, we designed and evaluated a novel fusion protein comprising HPV16 E7 antigen fused to Shiga toxin B-subunit (STxB) as both an antigen vector and an adjuvant. Then we designed two preventive and therapeutic tumor models to investigate the prevention and inhibition of TC-1 cell growth in female C57BL/6 mice, respectively. In each model, mice were immunized with the recombinant protein of E7-STxB or E7 without any adjuvant. Results: We demonstrated that prophylactic immunization of E7-STxB protected mice against TC-1 cells. Also in the therapeutic model, E7-STxB inhibited TC-1 tumor growth inlungs. The results were significant when compared with the immunization of E7 singularly. Conclusion: We concluded that immunization with the E7-STxB protein without any adjuvant could generate anti-tumor effect in mice challenged with TC-1 cells.This research verifies the clinical applications and the future prospects of developing HPV16 E7 therapeutic vaccines fused to immunoadjuvants. PMID:23862120

Sadraeian, Mohammad; Khoshnood Mansoorkhani, Mohammad Javad; Mohkam, Milad; Rasoul-Amini, Sara; Hesaraki, Mahdi; Ghasemi, Younes

2013-01-01

168

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

2011-12-01

169

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

SciTech Connect

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

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

2010-05-10

170

Production of Human Papillomavirus Type 16 E7 Protein in Lactococcus lactis  

PubMed Central

The E7 protein of human papillomavirus type 16 was produced in Lactococcus lactis. Secretion allowed higher production yields than cytoplasmic production. In stationary phase, amounts of cytoplasmic E7 were reduced, while amounts of secreted E7 increased, suggesting a phase-dependent intracellular proteolysis. Fusion of E7 to the staphylococcal nuclease, a stable protein, resulted in a highly stable cytoplasmic protein. This work provides new candidates for development of viral screening systems and for oral vaccine against cervical cancer. PMID:11823236

Bermudez-Humaran, L. G.; Langella, P.; Miyoshi, A.; Gruss, A.; Tamez Guerra, R.; Montes de Oca-Luna, R.; Le Loir, Y.

2002-01-01

171

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. PMID:23557172

2013-01-01

172

Human papillomavirus 16 E7 inactivator of retinoblastoma family proteins complements  

E-print Network

Human papillomavirus 16 E7 inactivator of retinoblastoma family proteins complements human tested whether the human papillomavirus type 16 E7 protein, which inactivates pRb family proteins necessary for cellular processes including DNA replication. Human cytomegalovirus (HCMV) UL97, a protein

173

The AD1 and AD2 Transactivation Domains of E2A Are Essential for the Antiapoptotic Activity of the Chimeric Oncoprotein E2A-HLF  

PubMed Central

The chimeric oncoprotein E2A-HLF, generated by the t(17;19) chromosomal translocation in pro-B-cell acute lymphoblastic leukemia, incorporates the transactivation domains of E2A and the basic leucine zipper (bZIP) DNA-binding and protein dimerization domain of HLF (hepatic leukemic factor). The ability of E2A-HLF to prolong the survival of interleukin-3 (IL-3)-dependent murine pro-B cells after IL-3 withdrawal suggests that it disrupts signaling pathways normally responsible for cell suicide, allowing the cells to accumulate as transformed lymphoblasts. To determine the structural motifs that contribute to this antiapoptotic effect, we constructed a panel of E2A-HLF mutants and programmed their expression in IL-3-dependent murine pro-B cells (FL5.12 line), using a zinc-inducible vector. Neither the E12 nor the E47 product of the E2A gene nor the wild-type HLF protein was able to protect the cells from apoptosis induced by IL-3 deprivation. Surprisingly, different combinations of disabling mutations within the HLF bZIP domain had little effect on the antiapoptotic property of the chimeric protein, so long as the amino-terminal portion of E2A remained intact. In the context of a bZIP domain defective in DNA binding, mutants retaining either of the two transactivation domains of E2A were able to extend cell survival after growth factor deprivation. Thus, the block of apoptosis imposed by E2A-HLF in pro-B lymphocytes depends critically on the transactivating regions of E2A. Since neither DNA binding nor protein dimerization through the bZIP domain of HLF is required for this effect, we propose mechanisms whereby protein-protein interactions with the amino-terminal region of E2A allow the chimera to act as a transcriptional cofactor to alter the expression of genes regulating the apoptotic machinery in pro-B cells. PMID:9742120

Inukai, Takeshi; Inaba, Toshiya; Ikushima, Satoshi; Look, A. Thomas

1998-01-01

174

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

PubMed Central

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

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

2013-01-01

175

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

PubMed

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

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

2013-01-01

176

Repression of MHC class I transcription by HPV16E7 through interaction with a putative RXR{beta} motif and NF-{kappa}B cytoplasmic sequestration  

SciTech Connect

Down-regulation of transcription of the MHC class I genes in HPV16 tumorigenic cells is partly due to HPV16E7 associated with the MHC class I promoter and repressed chromatin activation. In this study, we further demonstrated that HPV16E7 is physically associated with a putative RXR{beta} binding motif (GGTCA) of the proximal promoter of the MHC class I genes by using reporter transcriptional assays and chromatin immunoprecipitation assays. Our data also provide evidence that HPV16E7 inhibits TNF-{alpha}-induced up-regulation of MHC class I transcription by impaired nuclear translocation of NF-{kappa}B. More importantly, CaSki tumor cells treated with TSA and transfected with the constitutively active mutant form of IKK-{alpha} (which can activate NF-{kappa}B directly) showed a maximal level of up-regulation of MHC-I expression. Taken together, our results suggest that HPV16E7 may employ two independent mechanisms to ensure that either the constitutive or inducible transcription of MHC class I genes is down-regulated.

Li, Hui; Zhan, TaiLan; Li, Chang [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China)] [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China); Liu, Mugen, E-mail: lium@mail.hust.edu.cn [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China)] [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China); Wang, Qing K., E-mail: qkwang@mail.hust.edu.cn [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China); Center for Cardiovascular Genetics, Cleveland Clinic, Cleveland, OH 44195 (United States)

2009-10-16

177

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. PMID:24086435

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

2013-01-01

178

PDZ domain-binding motif of human T-cell leukemia virus type 1 Tax oncoprotein augments the transforming activity in a rat fibroblast cell line  

Microsoft Academic Search

While human T-cell leukemia virus type 1 (HTLV-1) is associated with the development of adult T-cell leukemia (ATL), HTLV-2 has not been reported to be associated with such malignant leukemias. HTLV-1 Tax1 oncoprotein transforms a rat fibroblast cell line (Rat-1) to form multiple large colonies in soft agar, and this activity is much greater than that of HTLV-2 Tax2. We

Akira Hirata; Masaya Higuchi; Akiko Niinuma; Minako Ohashi; Masaya Fukushi; Masayasu Oie; Tetsu Akiyama; Yuetsu Tanaka; Fumitake Gejyo; Masahiro Fujii

2004-01-01

179

Binding of Human Virus Oncoproteins to hDlg\\/SAP97, a Mammalian Homolog of the Drosophila Discs Large Tumor Suppressor Protein  

Microsoft Academic Search

The 9ORF1 gene encodes an adenovirus E4 region oncoprotein that requires a C-terminal region for transforming activity. Screening a lambda gt11 cDNA expression library with a 9ORF1 protein probe yielded a novel cellular PDZ domain-containing protein, 9BP-1, which binds to wildtype, but not a transformation-defective, C-terminal, mutant 9ORF1 protein. The fact that PDZ domains complex with specific sequences at the

Siu Sylvia Lee; Robert S. Weiss; Ronald T. Javier

1997-01-01

180

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

181

Overexpression of MDM2 oncoprotein correlates with possession of estrogen receptor alpha and lack of MDM2 mRNA splice variants in human breast cancer  

Microsoft Academic Search

To evaluate the significance of murine double minute 2 (MDM2) oncoprotein in human breast cancer as a nuclear-cytoplasmic shuttling protein, an estrogen receptor (ER) alpha regulator, and a prognostic marker and to study how MDM2 is overexpressed, we investigated its status in tissue samples and examined the correlation between overexpression and MDM2 gene abnormalities, status, and clinicopathological parameters. We detected

Masao Hori; Jiro Shimazaki; Satoshi Inagawa; Masayuki Itabashi; Mitsuo Hori

2002-01-01

182

Combined Stimulation of IL-2 and 4-1BB Receptors Augments the Antitumor Activity of E7 DNA Vaccines by Increasing Ag-Specific CTL Responses  

PubMed Central

Human papillomavirus (HPV) infection is a major cause of cervical cancer. Here, we investigate whether concurrent therapy using HPV E7 DNA vaccines (pE7) plus IL-2 vs. IL-15 cDNA and anti-4-1BB Abs might augment antitumor activity against established tumors. IL-2 cDNA was slightly better than IL-15 cDNA as a pE7 adjuvant. Co-delivery of pE7+IL-2 cDNA increased tumor cure rates from 7% to 27%, whereas co-delivery of pE7+IL-2 cDNA with anti-4-1BB Abs increased tumor cure rates from 27% to 67% and elicited long-term memory responses. This increased activity was concomitant with increased induction of Ag-specific CTL activity and IFN-? responses, but not with Ag-specific IgG production. Moreover, the combined stimulation of IL-2 and 4-1BB receptors with rIL-2 and anti-4-1BB Abs resulted in enhanced production of IFN-? from Ag-specific CD8+ T cells. However, this effect was abolished by treatment with anti-IL-2 Abs and 4-1BB-Fc, suggesting that the observed effect was IL-2- and anti-4-1BB Ab-specific. A similar result was also obtained for Ag-specific CTL activity. Thus, these studies demonstrate that combined stimulation through the IL-2 and 4-1BB receptors augments the Ag-specific CD8+ CTL responses induced by pE7, increasing tumor cure rates and long-term antitumor immune memory. These findings may have implications for the design of DNA-based therapeutic vaccines against cancer. PMID:24391824

Kim, Ha; Kwon, Byungsuk; Sin, Jeong-Im

2013-01-01

183

Interaction between BRCA1 and human papilloma virus E7: an ontology study  

Microsoft Academic Search

BRCA1 was the first breast cancer susceptibility gene to be identified and cloned. Recent studies indicate that BRCA 1 interacts with and regulates the activity of estrogen receptor alpha. The correlation between BRCA1 and E7 of papilloma virus becomes a new interesting topic in gynecological cancer. According to this study, E7 can add no function or aberration to the BRCA1

Viroj Wiwanitkit

2006-01-01

184

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

PubMed Central

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 compared with two previously described vaccinia virus constructs: one that expresses unmodified E7 (VacE7) and another that expresses E7 in a form designed to direct it to intracellular lysosomal compartments and improve major histocompatibility complex class II-restricted responses (VacSigE7LAMP-1). C57BL/6 mice bearing established HPV-16 immortalized tumors of 5 or 8 mm were treated with each of these vaccines. Fifty percent of the mice treated with VacLLOE7 remained tumor free 2 months after tumor inoculation, whereas 12 to 25% of the mice were tumor free after treatment with VacSigE7LAMP-1 (depending on the size of the tumor). No mice were tumor free in the group given VacE7. Compared to VacE7, VacSigE7LAMP-1 and VacLLOE7 resulted in increased numbers of H2-Db-specific tetramer-positive CD8+ T cells in mouse spleens that produced gamma interferon and tumor necrosis factor alpha upon stimulation with RAHYNIVTF peptide. In addition, the highest frequency of tetramer-positive T cells was seen in the tumor sites of mice treated with VacLLOE7. An increased efficiency of E7-specific lysis by splenocytes from mice immunized with VacLLOE7 was also observed. These results indicate that the fusion of E7 with LLO not only enhances antitumor therapy by improving the tumoricidal function of E7-specific CD8+ T cells but may also increase the number of antigen-specific CD8+ T cells in the tumor, the principle site of antigen expression. PMID:11559797

Lamikanra, Abigail; Pan, Zhen-Kun; Isaacs, Stuart N.; Wu, Tzyy-Choou; Paterson, Yvonne

2001-01-01

185

Negative regulation of the bovine papillomavirus E5, E6, and E7 oncogenes by the viral E1 and E2 genes.  

PubMed Central

Papillomaviruses induce benign squamous epithelial lesions that infrequently are associated with uncontrolled growth or malignant conversion. The virus-encoded oncogenes are clearly under negative regulation since papillomaviruses can latently infect cells and since different levels of viral oncogene expression are seen within the layers of differentiating infected epitheliomas. We used bovine papillomavirus type 1 (BPV-1) to investigate the mechanisms involved in the negative regulation of transformation. We found that the following two distinct and interacting mechanisms negatively regulate BPV-1 transformation effected by virally encoded trans-acting factors: (i) E2 repressors suppress transformation by the E6 and E7 oncogenes, and (ii) E1 and the E2 transactivator suppress transformation by the E6, E7, and E5 oncogenes. These systems interact in that the E2 repressors function to relieve the transformation suppression effected by the E1 and E2 transactivator genes. A BPV-1 mutant that lacked E2 repressors and E1 had greatly augmented transformation capacity. Analysis of this mutant revealed that the enhanced transformation was due to expression of the E6 and E7 genes in the absence of E5, revealing a previously unappreciated potency and synergy for the BPV-1 E6 and E7 oncogenes. PMID:7983735

Vande Pol, S B; Howley, P M

1995-01-01

186

Human papillomavirus type 8 E6 oncoprotein inhibits transcription of the PDZ protein syntenin-2.  

PubMed

The E6 proteins from high-risk alpha human papillomavirus (HPV) types (e.g., HPV16) are characterized by the presence of a PDZ-binding motif through which they interact with a number of cellular PDZ domain-containing substrates and cooperate in their degradation. The ability of these E6 proteins to bind to PDZ domain proteins correlates with the oncogenic potential of the virus. The E6 proteins of oncogenic HPV from the genus Betapapillomavirus (betaPV, e.g., HPV8) do not encode a PDZ-binding motif. We found that the PDZ domain protein syntenin-2 is transcriptionally downregulated in primary human epidermal keratinocytes (PHEK) by HPV8 E6. The mRNA levels of the known HPV16 E6 PDZ protein targets Dlg, Scribble, Magi-1, Magi-3, PSD95, and Mupp1 were not changed by HPV8 E6. Decreased protein levels of syntenin-2 were observed in cell extracts from PHEK expressing HPV5, -8, -16, -20, and -38 E6 but not in HPV1 and -4 E6-positive keratinocytes. Surprisingly, HPV16 E6 also repressed transcription of syntenin-2 but with a much lower efficiency than HPV8 E6. In healthy human skin, syntenin-2 expression is localized in suprabasal epidermal layers. In organotypic skin cultures, the differentiation-dependent expression of syntenin-2 was absent in HPV8 E6- and E6E7-expressing cells. In basal cell carcinomas of the skin, syntenin-2 was not detectable, whereas in squamous cell carcinomas, expression was located in differentiated areas. Short hairpin RNA-mediated knockdown of syntenin-2 led to an inhibition of differentiation and an increase in the proliferation capacity in PHEK. These results identified syntenin-2 as the first PDZ domain protein controlled by HPV8 and HPV16 at the mRNA level. PMID:22623796

Lazi?, Daliborka; Hufbauer, Martin; Zigrino, Paola; Buchholz, Stephanie; Kazem, Siamaque; Feltkamp, Mariet C W; Mauch, Cornelia; Steger, Gertrud; Pfister, Herbert; Akgül, Baki

2012-08-01

187

Human Papillomavirus Type 8 E6 Oncoprotein Inhibits Transcription of the PDZ Protein Syntenin-2  

PubMed Central

The E6 proteins from high-risk alpha human papillomavirus (HPV) types (e.g., HPV16) are characterized by the presence of a PDZ-binding motif through which they interact with a number of cellular PDZ domain-containing substrates and cooperate in their degradation. The ability of these E6 proteins to bind to PDZ domain proteins correlates with the oncogenic potential of the virus. The E6 proteins of oncogenic HPV from the genus Betapapillomavirus (betaPV, e.g., HPV8) do not encode a PDZ-binding motif. We found that the PDZ domain protein syntenin-2 is transcriptionally downregulated in primary human epidermal keratinocytes (PHEK) by HPV8 E6. The mRNA levels of the known HPV16 E6 PDZ protein targets Dlg, Scribble, Magi-1, Magi-3, PSD95, and Mupp1 were not changed by HPV8 E6. Decreased protein levels of syntenin-2 were observed in cell extracts from PHEK expressing HPV5, -8, -16, -20, and -38 E6 but not in HPV1 and -4 E6-positive keratinocytes. Surprisingly, HPV16 E6 also repressed transcription of syntenin-2 but with a much lower efficiency than HPV8 E6. In healthy human skin, syntenin-2 expression is localized in suprabasal epidermal layers. In organotypic skin cultures, the differentiation-dependent expression of syntenin-2 was absent in HPV8 E6- and E6E7-expressing cells. In basal cell carcinomas of the skin, syntenin-2 was not detectable, whereas in squamous cell carcinomas, expression was located in differentiated areas. Short hairpin RNA-mediated knockdown of syntenin-2 led to an inhibition of differentiation and an increase in the proliferation capacity in PHEK. These results identified syntenin-2 as the first PDZ domain protein controlled by HPV8 and HPV16 at the mRNA level. PMID:22623796

Lazic, Daliborka; Hufbauer, Martin; Zigrino, Paola; Buchholz, Stephanie; Kazem, Siamaque; Feltkamp, Mariet C. W.; Mauch, Cornelia; Steger, Gertrud; Pfister, Herbert

2012-01-01

188

Vaccination with an adenoviral vector expressing calreticulin-human papillomavirus 16 E7 fusion protein eradicates E7 expressing established tumors in mice  

Microsoft Academic Search

Background  Cervical cancer remains a leading cause of cancer-related mortality in women, particularly in developing countries. The causal\\u000a association between genital human papilloma virus (HPV) infection and cervical cancer has been firmly established, and the\\u000a oncogenic potential of certain HPV types has been clearly demonstrated. Vaccines targeting the oncogenic proteins, E6 and\\u000a E7 of HPV-16 and -18 are the focus of

Jorge G. Gomez-Gutierrez; Kutlu G. Elpek; Roberto Montes de Oca-Luna; Haval Shirwan; H. Sam Zhou; Kelly M. McMasters

2007-01-01

189

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

PubMed

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

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

2005-09-27

190

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

SciTech Connect

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

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

2013-05-03

191

Human Papilloma Virus (HPV) and Host Cellular Interactions  

Microsoft Academic Search

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

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

2008-01-01

192

Transforming properties of the cottontail rabbit papillomavirus oncoproteins Le6 and SE6 and of the E8 protein.  

PubMed Central

Cottontail rabbit papillomavirus induces on cottontail and domestic rabbits papillomas which progress at a high frequency to carcinoma. The virus encodes three transforming proteins; one is translated from open reading frame (ORF) E7 and binds the retinoblastoma protein, and two, LE6 and SE6, are translated from the first and second ATGs of ORF E6, respectively. Here we show that neither of the E6 proteins coprecipitated with p53 in vitro, nor did they bind to a recently identified E6-binding protein (J. J. Chen, C. E. Reid, V. Band, and E. Androphy, Science 269:529-531, 1995). This protein was shown to bind to the E6 proteins of the high-risk human papillomairus types 16 and 18 but not to the low-risk human papillomavirus types VI and II. In-frame deletions cloned into the pZipNeo vector were used to identify structural features of SE6 and LE6 important for transformation of NIH 3T3 cells. Three deletions covering the amino-terminal half of SE6 did not transform cells. In two of the three deletions, two Cys-X-X-Cys motifs were deleted, each deletion preventing the formation of one of the potential small Zn fingers of SE6. Among the LE6 deletions, only one had a reduced transformation efficiency, while seven transformed cells at least as efficiently as wild-type LE6. In each of three of these seven mutants, two Cys-X-X-Cys motifs were deleted. None of the three amino acid deletions which abolished transformation by SE6 reduced transformation by LE6. Furthermore, transformation did not correlate with the level of SE6 or LE6 proteins detectable. ORF E8 colinear with ORF E6, which could generate a 50-amino-acid protein with a hydrophobic segment, did not transform cells when cloned into the pZipNeo vector. However, mutation of the E8 ATG, which did not alter the amino acid sequence of LE6, increased transformation by LE6 without affecting the level of LE6 expression. The data suggest that transformation by the E6 proteins is not mediated by interfering with p53 function or through binding to the E6-binding protein. Furthermore, different structural features are important to maintain transformation functions and protein stability of LE6 and SE6. Finally, E8 seems not to be a transforming protein but rather appears to modulate transformation bv LE6. PMID:8648665

Harry, J B; Wettstein, F O

1996-01-01

193

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. PMID:23880157

2013-01-01

194

Amino-terminal Enhancer of Split (AES) Interacts with the Oncoprotein NUP98-HOXA9 and Enhances Its Transforming Ability*  

PubMed Central

NUP98-HOXA9 is the prototype of NUP98 fusion oncoproteins that cause acute myeloid leukemia. It consists of an N-terminal FG-rich portion of the nucleoporin NUP98 fused to the homeodomain region of the homeobox protein HOXA9, and acts as an aberrant transcription factor. To identify interacting partners of NUP98-HOXA9, we used a cytoplasmic yeast two-hybrid assay to avoid the nonspecific trans-activation that would occur with the traditional yeast two-hybrid assay due to the transactivating properties of NUP98-HOXA9. We identified amino-terminal enhancer of split (AES), a transcriptional regulator of the transducin-like enhancer/Groucho family as a novel interaction partner of NUP98-HOXA9. The interaction was confirmed by in vitro pulldown and co-immunoprecipitation assays and was shown to require the FG repeat region of NUP98-HOXA9. Immunofluorescence analysis showed that AES localizes primarily to the interior of the nucleus. AES also showed a strong interaction with wild-type NUP98. AES augmented the transcriptional activity of NUP98-HOXA9. In the presence of NUP98-HOXA9, AES caused an increase in long-term proliferation of primary human CD34+ cells with a marked increase in the numbers of primitive cells. These effects of AES were not observed in the absence of NUP98-HOXA9. AES knockdown diminished the transcriptional and proliferative effects of NUP98-HOXA9. AES caused a shift away from the erythroid lineage in cells expressing NUP98-HOXA9. These data establish AES as an interacting partner of NUP98-HOXA9 and show that it cooperates with NUP98-HOXA9 in transcriptional regulation and cell transformation. PMID:21937451

Sarma, Nayan J.; Yaseen, Nabeel R.

2011-01-01

195

Refractive indices of the nematic mixture E7 at 1550 nm  

NASA Astrophysics Data System (ADS)

We give a measurement of the refractive indices of the nematic liquid crystal E7 at a wavelength of 1550 nm as a function of temperature. This particular wavelength has been chosen because it is very important in telecommunications. The measurements have been performed by means of a refractometric method, using a wedge shaped liquid crystal cell.

Brugioni, S.; Meucci, R.

2007-01-01

196

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  

Microsoft Academic Search

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

Yan Li; Yan Zhu; Lin Zhou; Yimin Fang; Lirong Huang; Liangliang Ren; Yi Peng; Yifen Li; Fangfang Yang; Dan Xie; Wenzheng Tang; Na Zhang; Qiu Zhong; Xiaomin Lai

2011-01-01

197

Targeting Oncoprotein Stability Overcomes Drug Resistance Caused by FLT3 Kinase Domain Mutations  

PubMed Central

FLT3 is the most frequently mutated kinase in acute myeloid leukemia (AML). Internal tandem duplications (ITDs) in the juxta-membrane region constitute the majority of activating FLT3 mutations. Several FLT3 kinase inhibitors were developed and tested in the clinic with significant success. However, recent studies have reported the development of secondary drug resistance in patients treated with FLT3 inhibitors. Since FLT3-ITD is an HSP90 client kinase, we here explored if targeting the stability of drug-resistant FLT3 mutant protein could be a potential therapeutic option. We observed that HSP90 inhibitor treatment resulted in the degradation of inhibitor-resistant FLT3-ITD mutants and selectively induced toxicity in cells expressing FLT3-ITD mutants. Thus, HSP90 inhibitors provide a potential therapeutic choice to overcome secondary drug resistance following TKI treatment in FLT3-ITD positive AML. PMID:24849514

Duyster, Justus

2014-01-01

198

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

2013-01-01

199

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

PubMed

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 vaccines by employing different lengths of CRT chimerically linked to a model antigen HPV6bE7 and investigated the immunological and antiangiogenic effects of these vaccines in a B16 melanoma model that express HPV6bE7 antigen. Our results showed that vaccination with CRT180/HPV6bE7 or CRT120/HPV6bE7 enhanced the presence of CD8(+) T cells and TCRgammadelta T cells in vivo, increased the specific lysis activity against E7-expressing cells and secretion levels of IL-2 and IFN-gamma by activating T cells in vitro significantly. Moreover, recombined CRT180 or CRT120 with HPV6bE7 vaccines could elicit a more efficient E7-specific immune response than HPV6bE7 alone. The similarity of immunological enhancement of CRT180/HPV6bE7 and CRT120/HPV6bE7 implies that the immunologically active region mainly exist in fragment 1-120 aa. Furthermore, CRT180/HPV6bE7 and CRT180 displayed remarkable superiority over CRT120/HPV6bE7 in vivo angiogenesis assay, suggesting that the antiangiogenic activity of CRT resides in a domain between aa 120 and 180. Vaccination with CRT180/HPV6bE7 generated the best protective effect of delaying tumor formation and reduction of tumor size in tumor growth inhibition experiment among all DNA constructs. Therefore, CRT180/HPV6bE7 vaccine may enhance the immunological response to HPV6bE7 and inhibit angiogenesis. This construct may be useful in preventing HPV-associated dermatosis and may be developed as a promising strategy to control CA. PMID:16710741

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

2006-07-01

200

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

Microsoft Academic Search

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

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

2005-01-01

201

The germinal center kinase TNIK is required for canonical NF-?B and JNK signaling in B-cells by the EBV oncoprotein LMP1 and the CD40 receptor.  

PubMed

The tumor necrosis factor-receptor-associated factor 2 (TRAF2)- and Nck-interacting kinase (TNIK) is a ubiquitously expressed member of the germinal center kinase family. The TNIK functions in hematopoietic cells and the role of TNIK-TRAF interaction remain largely unknown. By functional proteomics we identified TNIK as interaction partner of the latent membrane protein 1 (LMP1) signalosome in primary human B-cells infected with the Epstein-Barr tumor virus (EBV). RNAi-mediated knockdown proved a critical role for TNIK in canonical NF-?B and c-Jun N-terminal kinase (JNK) activation by the major EBV oncoprotein LMP1 and its cellular counterpart, the B-cell co-stimulatory receptor CD40. Accordingly, TNIK is mandatory for proliferation and survival of EBV-transformed B-cells. TNIK forms an activation-induced complex with the critical signaling mediators TRAF6, TAK1/TAB2, and IKK?, and mediates signalosome formation at LMP1. TNIK directly binds TRAF6, which bridges TNIK's interaction with the C-terminus of LMP1. Separate TNIK domains are involved in NF-?B and JNK signaling, the N-terminal TNIK kinase domain being essential for IKK?/NF-?B and the C-terminus for JNK activation. We therefore suggest that TNIK orchestrates the bifurcation of both pathways at the level of the TRAF6-TAK1/TAB2-IKK complex. Our data establish TNIK as a novel key player in TRAF6-dependent JNK and NF-?B signaling and a transducer of activating and transforming signals in human B-cells. PMID:22904686

Shkoda, Anna; Town, Jennifer A; Griese, Janine; Romio, Michael; Sarioglu, Hakan; Knöfel, Thomas; Giehler, Fabian; Kieser, Arnd

2012-01-01

202

Differential transforming activity of the retroviral Tax oncoproteins in human T lymphocytes  

PubMed Central

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

2013-01-01

203

BCR-ABL1 promotes leukemia by converting p27 into a cytoplasmic oncoprotein.  

PubMed

Recent studies have revealed that p27, a nuclear cyclin-dependent kinase (Cdk) inhibitor and tumor suppressor, can acquire oncogenic activities upon mislocalization to the cytoplasm. To understand how these antagonistic activities influence oncogenesis, we dissected the nuclear and cytoplasmic functions of p27 in chronic myeloid leukemia (CML), a well-characterized malignancy caused by the BCR-ABL1 tyrosine kinase. p27 is predominantly cytoplasmic in CML and nuclear in normal cells. BCR-ABL1 regulates nuclear and cytoplasmic p27 abundance by kinase-dependent and -independent mechanisms, respectively. p27 knockdown in CML cell lines with predominantly cytoplasmic p27 induces apoptosis, consistent with a leukemogenic role of cytoplasmic p27. Accordingly, a p27 mutant (p27(CK-)) devoid of Cdk inhibitory nuclear functions enhances leukemogenesis in a murine CML model compared with complete absence of p27. In contrast, p27 mutations that enhance its stability (p27(T187A)) or nuclear retention (p27(S10A)) attenuate leukemogenesis over wild-type p27, validating the tumor-suppressor function of nuclear p27 in CML. We conclude that BCR-ABL1 kinase-dependent and -independent mechanisms convert p27 from a nuclear tumor suppressor to a cytoplasmic oncogene. These findings suggest that cytoplasmic mislocalization of p27 despite BCR-ABL1 inhibition by tyrosine kinase inhibitors may contribute to drug resistance, and effective therapeutic strategies to stabilize nuclear p27 must also prevent cytoplasmic mislocalization. PMID:25293778

Agarwal, Anupriya; Mackenzie, Ryan J; Besson, Arnaud; Jeng, Sophia; Carey, Alyssa; LaTocha, Dorian H; Fleischman, Angela G; Duquesnes, Nicolas; Eide, Christopher A; Vasudevan, Kavin B; Loriaux, Marc M; Firpo, Eduardo; Cortes, Jorge E; McWeeney, Shannon; O'Hare, Thomas; Roberts, James M; Druker, Brian J; Deininger, Michael W

2014-11-20

204

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

PubMed

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

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

2011-03-01

205

Glioma oncoprotein Bcl2L12 inhibits the p53 tumor suppressor  

PubMed Central

Glioblastoma multiforme (GBM) is a lethal brain tumor characterized by intense apoptosis resistance and extensive necrosis. Bcl2L12 (for Bcl2-like 12) is a cytoplasmic and nuclear protein that is overexpressed in primary GBM and functions to inhibit post-mitochondrial apoptosis signaling. Here, we show that nuclear Bcl2L12 physically and functionally interacts with the p53 tumor suppressor, as evidenced by the capacity of Bcl2L12 to (1) enable bypass of replicative senescence without concomitant loss of p53 or p19Arf, (2) inhibit p53-dependent DNA damage-induced apoptosis, (3) impede the capacity of p53 to bind some of its target gene promoters, and (4) attenuate endogenous p53-directed transcriptomic changes following genotoxic stress. Correspondingly, The Cancer Genome Atlas profile and tissue protein analyses of human GBM specimens show significantly lower Bcl2L12 expression in the setting of genetic p53 pathway inactivation. Thus, Bcl2L12 is a multifunctional protein that contributes to intense therapeutic resistance of GBM through its ability to operate on two key nodes of cytoplasmic and nuclear signaling cascades. PMID:20837658

Stegh, Alexander H.; Brennan, Cameron; Mahoney, John A.; Forloney, Kristin L.; Jenq, Harry T.; Luciano, Janina P.; Protopopov, Alexei; Chin, Lynda; DePinho, Ronald A.

2010-01-01

206

Glioma oncoprotein Bcl2L12 inhibits the p53 tumor suppressor.  

PubMed

Glioblastoma multiforme (GBM) is a lethal brain tumor characterized by intense apoptosis resistance and extensive necrosis. Bcl2L12 (for Bcl2-like 12) is a cytoplasmic and nuclear protein that is overexpressed in primary GBM and functions to inhibit post-mitochondrial apoptosis signaling. Here, we show that nuclear Bcl2L12 physically and functionally interacts with the p53 tumor suppressor, as evidenced by the capacity of Bcl2L12 to (1) enable bypass of replicative senescence without concomitant loss of p53 or p19 (Arf), (2) inhibit p53-dependent DNA damage-induced apoptosis, (3) impede the capacity of p53 to bind some of its target gene promoters, and (4) attenuate endogenous p53-directed transcriptomic changes following genotoxic stress. Correspondingly, The Cancer Genome Atlas profile and tissue protein analyses of human GBM specimens show significantly lower Bcl2L12 expression in the setting of genetic p53 pathway inactivation. Thus, Bcl2L12 is a multifunctional protein that contributes to intense therapeutic resistance of GBM through its ability to operate on two key nodes of cytoplasmic and nuclear signaling cascades. PMID:20837658

Stegh, Alexander H; Brennan, Cameron; Mahoney, John A; Forloney, Kristin L; Jenq, Harry T; Luciano, Janina P; Protopopov, Alexei; Chin, Lynda; Depinho, Ronald A

2010-10-01

207

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

208

Targeting Epstein-Barr virus oncoprotein LMP1-mediated glycolysis sensitizes nasopharyngeal carcinoma to radiation therapy.  

PubMed

Our goal in this work was to illustrate the Epstein-Barr virus (EBV)-modulated global biochemical profile and provide a novel metabolism-related target to improve the therapeutic regimen of nasopharyngeal carcinoma (NPC). We used a metabolomics approach to investigate EBV-modulated metabolic changes, and found that the exogenous overexpression of the EBV-encoded latent membrane protein 1 (LMP1) significantly increased glycolysis. The deregulation of several glycolytic genes, including hexokinase 2 (HK2), was determined to be responsible for the reprogramming of LMP1-mediated glucose metabolism in NPC cells. The upregulation of HK2 elevated aerobic glycolysis and facilitated proliferation by blocking apoptosis. More importantly, HK2 was positively correlated with LMP1 in NPC biopsies, and high HK2 levels were significantly associated with poor overall survival of NPC patients following radiation therapy. Knockdown of HK2 effectively enhanced the sensitivity of LMP1-overexpressing NPC cells to irradiation. Finally, c-Myc was demonstrated to be required for LMP1-induced upregulation of HK2. The LMP1-mediated attenuation of the PI3-K/Akt-GSK3beta-FBW7 signaling axis resulted in the stabilization of c-Myc. These findings indicate a close relationship between EBV and glycolysis in NPC. Notably, LMP1 is the key regulator of the reprogramming of EBV-mediated glycolysis in NPC cells. Given the importance of EBV-mediated deregulation of glycolysis, anti-glycolytic therapy might represent a worthwhile avenue of exploration in the treatment of EBV-related cancers. PMID:24662831

Xiao, L; Hu, Z-Y; Dong, X; Tan, Z; Li, W; Tang, M; Chen, L; Yang, L; Tao, Y; Jiang, Y; Li, J; Yi, B; Li, B; Fan, S; You, S; Deng, X; Hu, F; Feng, L; Bode, A M; Dong, Z; Sun, L-Q; Cao, Y

2014-09-11

209

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

2010-12-01

210

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

2013-09-23

211

Myc and Human Papillomavirus Type 16 E7 Genes Cooperate To Immortalize Human Keratinocytes  

Microsoft Academic Search

The E6 protein of the oncogenic human papillomaviruses (HPVs), in combination with the E7 protein, is essential for the efficient immortalization of human foreskin keratinocytes (HFKs). Since we recently demon- strated that E6 activates the human telomerase reverse transcriptase (hTERT) promoter via a Myc-dependent mechanism, we speculated that overexpressed Myc might be able to substitute for E6 in cell immortalization.

Xuefeng Liu; Gary L. Disbrow; Hang Yuan; Vjekoslav Tomaic; Richard Schlegel

2007-01-01

212

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. PMID:1712110

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

1991-01-01

213

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

SciTech Connect

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

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

2012-08-10

214

HPV18 E6 and E7 genes affect cell cycle, pRB and p53 of cervical tumor cells and represent prominent candidates for intervention by use peptide nucleic acids (PNAs).  

PubMed

Approximately 100% of cervical carcinomas are causally linked to infections with high-risk human papillomaviruses (HPVs), whose oncogenicity has been assigned to the continued expression of two early viral genes, E6 and E7. Reversal of the transformed phenotype by inhibiting E6/E7 gene expression therefore provides a suitable goal for tumor therapy. We established an application controlling the E6/E7 expression of the HPV type 18, by using viral gene directed peptide nucleic acids (PNAs). One consequence was the complete change in growth to a stagnated behavior of the HPV 18 positive HeLa-S cells. With flow cytometry, we investigated changes in the cell cycle and expression of the pRB (retinoblastoma) and p53 genes acting as antagonists to E6 and E7. We realized that application of PNAs via intracellular cleavable conjugated peptide carriers mediates specific inhibitory effects and we showed that the combined E6/E7-directed PNA-application mediated a clear morphological change from suspension to adherend state and the cells stopped growth. These data could demonstrate a promising approach for development of new 'anti-gene therapeutics' against papillomavirus-induced human cancers. PMID:15145519

Braun, Klaus; Ehemann, Volker; Waldeck, Waldemar; Pipkorn, Rüdiger; Corban-Wilhelm, Heike; Jenne, Jürgen; Gissmann, Lutz; Debus, Jürgen

2004-06-01

215

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

216

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

217

Oncoprotein protein kinase  

DOEpatents

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

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

1997-01-01

218

Oncoprotein protein kinase  

DOEpatents

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

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

2003-02-04

219

Oncoprotein protein kinase  

DOEpatents

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

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

1999-01-01

220

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

221

Oncoprotein protein kinase  

DOEpatents

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

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

1997-01-01

222

Oncoprotein protein kinase  

DOEpatents

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

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

1998-01-01

223

Oncoprotein protein kinase  

DOEpatents

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

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

1997-02-25

224

Oncoprotein protein kinase  

DOEpatents

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

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

1999-11-30

225

Berberine modulates AP-1 activity to suppress HPV transcription and downstream signaling to induce growth arrest and apoptosis in cervical cancer cells  

PubMed Central

Background- Specific types of high risk Human papillomaviruses (HR-HPVs) particularly, HPV types 16 and 18 cause cervical cancer and while the two recently developed vaccines against these HPV types are prophylactic in nature, therapeutic options for treatment and management of already existing HPV infection are not available as yet. Because transcription factor, Activator Protein-1 (AP-1) plays a central role in HPV-mediated cervical carcinogenesis, we explored the possibility of its therapeutic targeting by berberine, a natural alkaloid derived from a medicinal plant species, Berberis which has been shown to possess anti-inflammatory and anti-cancer properties with no known toxicity; however, the effect of berberine against HPV has not been elucidated. Results- We studied the effect of berberine on HPV16-positive cervical cancer cell line, SiHa and HPV18-positive cervical cancer cell line, HeLa using electrophoretic mobility gel shift assays, western and northern blotting which showed that berberine could selectively inhibit constitutively activated AP-1 in a dose- and time-dependent manner and downregulates HPV oncogenes expression. Inhibition of AP-1 was also accompanied by changes in the composition of their DNA-binding complex. Berberine specifically downregulated expression of oncogenic c-Fos which was also absent in the AP-1 binding complex. Treatment with berberine resulted in repression of E6 and E7 levels and concomitant increase in p53 and Rb expression in both cell types. Berberine also suppressed expression of telomerase protein, hTERT, which translated into growth inhibition of cervical cancer cells. Interestingly, a higher concentration of berberine was found to reduce the cell viability through mitochondria-mediated pathway and induce apoptosis by activating caspase-3. Conclusion- These results indicate that berberine can effectively target both the host and viral factors responsible for development of cervical cancer through inhibition of AP-1 and blocking viral oncoproteins E6 and E7 expression. Inhibition of AP-1 activity by berberine may be one of the mechanisms responsible for the anti-HPV effect of berberine. We propose that berberine is a potentially promising compound for the treatment of cervical cancer infected with HPV. PMID:21496227

2011-01-01

226

Interaction of Human Papillomavirus 8 Regulatory Proteins E2, E6 and E7 with Components of the TFIID Complex  

Microsoft Academic Search

SummaryHuman papillomavirus 8 (HPV8) is one of the oncogenic HPV types specifically associated with skin cancers of epidermodysplasia verruciformis patients. The early gene products of this virus exert functions in transformation (E2, E6, E7), replication (E1, E2) and in the control of viral transcription (E2, E7). Many viral and cellular transactivators of transcription have been shown to interact selectively and

Christina Enzenauer; Gabrielle Mengus; Anne-Claire Lavigne; Irwin Davidson; Herbert Pfister; Michael May

1998-01-01

227

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

Microsoft Academic Search

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

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

1995-01-01

228

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

PubMed Central

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

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

2014-01-01

229

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

PubMed Central

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

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

2014-01-01

230

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

SciTech Connect

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

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

2011-08-26

231

T-helper epitopes of the E7 transforming protein of cervical cancer associated human papillomavirus type 18 (HPV18).  

PubMed

The presence of T-helper epitopes within the E7 transforming protein of human papillomavirus type 18 (HPV18) was sought using a series of overlapping synthetic 15-20 mer peptides spanning the entire 105 amino acid sequence of this protein. Two H-2k restricted T-helper epitopes were defined, comprising 44VNHQHLPARRA55 and 81DDLRAFQQLF90 as the minimal T proliferative epitopes. Peptides containing these epitopes were able to provide cognate help to B epitopes from HPV18E7 protein for production of antibody to this protein in vivo in CBA/CaH mice. No H-2b or H-2d restricted epitopes were demonstrable, and in H-2d mice this was associated with poor antibody response to the E7 protein. There is no "promiscuous" T-helper epitope in HPV18 E7 comparable to the 49DRAHYNI55 sequence in HPV16 E7, and restricted T-helper epitope availability may be a determinant of poor immune responses to this protein after natural infection. PMID:7542826

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

1995-04-01

232

Global Effects of Human Papillomavirus Type 18 E6/E7 in an Organotypic Keratinocyte Culture System†  

PubMed Central

The effects of human papillomavirus type 18 (HPV-18) E6 and E7 proteins on global patterns of host gene expression in primary human keratinocytes grown in organotypic raft culture system were assessed. Primary human keratinocytes were infected with retroviruses that express the wild-type HPV-18 E6 and E7 genes from the native differentiation-dependent HPV enhancer-promoter. Total RNA was isolated from raft cultures and used to generate probes for querying Affymetrix U95A microarrays, which contain >12,500 human gene sequences. Quadruplicate arrays of each E6/E7-transduced and empty vector-transduced samples were analyzed by 16 pairwise comparisons. Transcripts altered in ?12 comparisons were selected for further analysis. With this approach, HPV-18 E6/E7 expression significantly altered the expression of 1,381 genes. A large increase in transcripts associated with DNA and RNA metabolism was observed, with major increases noted for transcription factors, splicing factors, and DNA replication elements, among others. Multiple genes associated with protein translation were downregulated. In addition, major alterations were found in transcripts associated with the cell cycle and cell differentiation. Our study provides a systematic description of transcript changes brought about by HPV-18 E6/E7 in a physiologically relevant model and should furnish a solid source of information to guide future studies. PMID:15308700

Garner-Hamrick, Peggy A.; Fostel, J. M.; Chien, Wei-Ming; Banerjee, N. Sanjib; Chow, Louise T.; Broker, Thomas R.; Fisher, Chris

2004-01-01

233

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 PMID:8692833

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

1996-01-01

234

Ha-rasval12 induces HSP70b transcription via the HSE\\/HSF1 system, but HSP70b expression is suppressed in Ha-rasval12-transformed cells  

Microsoft Academic Search

Heat shock proteins (Hsps) are overexpressed in many tumors, but are downregulated in some tumors. To check for a direct effect of Ha-Rasval12 on HSP70 transcription, we transiently expressed the oncoprotein in Rat1 fibroblasts and monitored its effect on HSP70b promoter-driven reporter gene. We show that expression of Ha-Rasval12 induced this promoter. Promoter analysis via systematic deletions and point mutations

A Stanhill; V Levin; A Hendel; I Shachar; D Kazanov; N Arber; N Kaminski; D Engelberg

2006-01-01

235

A fluorescent nanoprobe based on graphene oxide fluorescence resonance energy transfer for the rapid determination of oncoprotein vascular endothelial growth factor (VEGF).  

PubMed

Oncoprotein vascular endothelial growth factor (VEGF) is one of the most critical growth factors that regulates tumor growth and division. The vascular endothelial growth factor (VEGF) is also an important biomarker for different diseases and clinical disorders. Herein, we propose a graphene oxide (GO) fluorescence resonance energy transfer (FRET)-based aptasensor for rapid, sensitive, and selective detection of VEGF in homogeneous solution. The fluorescent dye-labeled anti-VEGF aptamer is adsorbed on the surface of GO via ?-? interaction between the flat planar GO sheets and the ring structures in the nucleobases, which results in the fluorescence quenching of the dye due to the highly effective FRET from the dye to GO. Upon recognition and binding with the target VEGF, it specifically forms a VEGF/aptamer complex and then release from the GO surface, leading to the restoration of fluorescence signal of the dye. This GO-based sensing platform exhibits high sensitivity and specificity toward VEGF versus other proteins, with the detection limits corresponding to 2.5×10(-10) M. The sensitivity of this new type of aptamer-based assay is at least one order of magnitude higher than that of conventional homogeneous optical assays. Moreover, the application of this nanosensor for human serum sample analysis is also demonstrated. The GO/aptamer-based assay approach holds great promise as a general platform for detection of a variety of target molecules. PMID:24160878

Wang, Sheng-E; Si, Shihui

2013-11-01

236

Targeting of N-CoR and histone deacetylase 3 by the oncoprotein v-erbA yields a chromatin infrastructure-dependent transcriptional repression pathway.  

PubMed

Transcriptional repression by nuclear hormone receptors is thought to result from a unison of targeting chromatin modification and disabling the basal transcriptional machinery. We used Xenopus oocytes to compare silencing effected by the thyroid hormone receptor (TR) and its mutated version, the oncoprotein v-ErbA, on partly and fully chromatinized TR-responsive templates in vivo. Repression by v-ErbA was not as efficient as that mediated by TR, was significantly more sensitive to histone deacetylase (HDAC) inhibitor treatment and, unlike TR, v-ErbA required mature chromatin to effect repression. We find that both v-ErbA and TR can recruit the corepressor N-CoR, but, in contrast to existing models, show a concomitant enrichment for HDAC3 that occurs without an association with Sin3, HDAC1/RPD3, Mi-2 or HDAC5. We propose a requirement for chromatin infrastructure in N-CoR/HDAC3-effected repression and suggest that the inability of v-ErbA to silence on partly chromatinized templates may stem from its impaired capacity to interfere with basal transcriptional machinery function. In support of this notion, we find v-ErbA to be less competent than TR for binding to TFIIB in vitro and in vivo. PMID:10921888

Urnov, F D; Yee, J; Sachs, L; Collingwood, T N; Bauer, A; Beug, H; Shi, Y B; Wolffe, A P

2000-08-01

237

The HBx Oncoprotein of Hepatitis B Virus Deregulates the Cell Cycle by Promoting the Intracellular Accumulation and Re-Compartmentalization of the Cellular Deubiquitinase USP37  

PubMed Central

The HBx oncoprotein of hepatitis B Virus has been accredited as one of the protagonists in driving hepatocarcinogenesis. HBx exerts its influence over the cell cycle progression by potentiating the activity of cyclin A/E-CDK2 complex, the Cyclin A partner of which is a well-known target of cellular deubiquitinase USP37. In the present study, we observed the intracellular accumulation of cyclin A and USP37 proteins under the HBx microenvironment. Flow cytometry analysis of the HBx-expressing cells showed deregulation of cell cycle apparently due to the enhanced gene expression and stabilization of USP37 protein and deubiquitination of Cyclin A by USP37. Our co-immunoprecipitation and confocal microscopic studies suggested a direct interaction between USP37 and HBx. This interaction promoted the translocation of USP37 outside the nucleus and prevented its association and ubiquitination by E3 ubiquitin ligases - APC/CDH1 and SCF/?-TrCP. Thus, HBx seems to control the cell cycle progression via the cyclin A-CDK2 complex by regulating the intracellular distribution and stability of deubiquitinase USP37. PMID:25347529

Saxena, Nehul; Kumar, Vijay

2014-01-01

238

Refractive indices of liquid crystals E7 and K15 in the mid- and near-IR regions  

NASA Astrophysics Data System (ADS)

This paper presents the results of refractive-index measurements of the extraordinary and ordinary rays in nematic liquid crystals (NLCs) using a refractometric technique in the mid-IR (?=10.6?µm) and near-IR (?=1550?nm) regions for NLC E7 and at ?=1550?nm for NLC K15. The optical anisotropy of NLC E7 at 10.6?µm is determined independently by means of the interferometric method in order to compare it with the results obtained by the refractometric technique.

Brugioni, S.; Meucci, R.; Faetti, S.

2006-05-01

239

Characterization of human aortic smooth muscle cells expressing HPV16 E6 and E7 open reading frames.  

PubMed Central

A comparative study of human papillomavirus type 16 E6E7-transfected and normal human aortic smooth muscle cells by morphological, electron microscopic, immunofluorescent, and biochemical analyses demonstrated that the E6E7-expressing cells retained much of the phenotype of normal aortic smooth muscle cells, including expression of smooth muscle markers and appropriate growth responses to PDGF and heparin. These cells differed from normal vascular smooth muscle cells in that they had slightly altered morphology and a higher growth rate that was not due to an autocrine response to secreted PDGF, and they contained more polyribosomes than normal smooth muscle cells. Images Figure 2 Figure 4 Figure 5 PMID:7677186

Conroy, S. C.; Hart, C. E.; Perez-Reyes, N.; Giachelli, C. M.; Schwartz, S. M.; McDougall, J. K.

1995-01-01

240

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

241

Journal of Crystal Growth 275 (2005) e7e13 Numerical study of three-dimensional instabilities in a  

E-print Network

Journal of Crystal Growth 275 (2005) e7­e13 Numerical study of three-dimensional instabilities the necessary prac- tical answers. In the case of crystal growth, for example, stabilizing the primary of axisym- metric flows in the Czochralski model and simplified flow models related to crystal growth

Gelfgat, Alexander

242

A sequence-specific RNase activity derived from the interface of the dimeric immunity protein of the ColE7 operon.  

PubMed

Recently, two sequence-specific cleavage sites were found in the ceiE7 gene of the cea-cei-cel polycistronic transcript from the ColE7 operon. The crystal structure of the ColE7 immunity protein (ImE7) suggested that a novel ribonuclease active site is created at the interface of the dimeric structure of the protein. Frame shift mutation of the ceiE7 gene and mutation of histidine residues at the putative active site of the dimeric ImE7 protein respectively abolished and significantly reduced the observed ribonucleolytic cleavage indicating that the dimeric ImE7 protein is indeed involved in this sequence-specific cleavage at the ceiE7 mRNA. It is noteworthy that E. coli S-30 cell extracts must be added to the in vitro reactions in order to detect this ribonucleolytic cleavage. In addition, mutation of the T1 stem-loop structure located between the ceiE7 and the celE7 genes completely turned off the ribonuclease activity in vivo, implying that the T1 stem-loop structure might participate in mediating the formation of a degradosome-like complex required for this specific ribonucleolytic activity. PMID:17305601

Liao, Chen-Chung; Chang, Ssu-Jean; Chak, Kin-Fu

2007-01-01

243

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

PubMed Central

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

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

2008-01-01

244

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

PubMed

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

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

2001-12-01

245

Expression of hepatitis B virus X oncoprotein inhibits transcription-coupled nucleotide excision repair in human cells  

Microsoft Academic Search

The hepatitis B virus X protein (HBx) is implicated in liver cancer development, and this presumably involves its ability to bind and functionally inactivate the p53 tumour suppressor. For example expression of HBx in cultured cells has been shown to inhibit global nucleotide excision repair, a p53-dependent subpathway of nucleotide excision repair (NER) which eliminates helix-distorting DNA adducts, e.g., UV-induced

Géraldine Mathonnet; Silvana Lachance; Moulay Alaoui-Jamali; Elliot A. Drobetsky

2004-01-01

246

MUC1-C oncoprotein activates the ZEB1/miR-200c regulatory loop and epithelial-mesenchymal transition.  

PubMed

The epithelial-mesenchymal transition (EMT) is activated in cancer cells by ZEB1, a member of the zinc finger/homeodomain family of transcriptional repressors. The mucin 1 (MUC1) heterodimeric protein is aberrantly overexpressed in human carcinoma cells. The present studies in breast cancer cells demonstrate that the oncogenic MUC1-C subunit induces expression of ZEB1 by a NF-?B (nuclear factor kappa B) p65-dependent mechanism. MUC1-C occupies the ZEB1 promoter with NF-?B p65 and thereby promotes ZEB1 transcription. In turn, ZEB1 associates with MUC1-C and the ZEB1/MUC1-C complex contributes to the transcriptional suppression of miR-200c, an inducer of epithelial differentiation. The co-ordinate upregulation of ZEB1 and suppression of miR-200c has been linked to the induction of EMT. In concert with the effects of MUC1-C on ZEB1 and miR-200c, we show that MUC1-C induces EMT and cellular invasion by a ZEB1-mediated mechanism. These findings indicate that (i) MUC1-C activates ZEB1 and suppresses miR-200c with the induction of EMT and (ii) targeting MUC1-C could be an effective approach for the treatment of breast and possibly other types of cancers that develop EMT properties. PMID:23584475

Rajabi, H; Alam, M; Takahashi, H; Kharbanda, A; Guha, M; Ahmad, R; Kufe, D

2014-03-27

247

Bovine Papillomavirus Type 2 (BPV-2) E5 Oncoprotein Binds to the Subunit D of the V1-ATPase Proton Pump in Naturally Occurring Urothelial Tumors of the Urinary Bladder of Cattle  

PubMed Central

Background Active infection by bovine papillomavirus type 2 (BPV-2) was documented for fifteen urinary bladder tumors in cattle. Two were diagnosed as papillary urothelial neoplasm of low malignant potential (PUNLMP), nine as papillary and four as invasive urothelial cancers. Methods and Findings In all cancer samples, PCR analysis revealed a BPV-2-specific 503 bp DNA fragment. E5 protein, the major oncoprotein of the virus, was shown both by immunoprecipitation and immunohistochemical analysis. E5 was found to bind to the activated (phosphorylated) form of the platelet derived growth factor ? receptor. PDGF?R immunoprecipitation from bladder tumor samples and from normal bladder tissue used as control revealed a protein band which was present in the pull-down from bladder cancer samples only. The protein was identified with mass spectrometry as “V1-ATPase subunit D”, a component of the central stalk of the V1-ATPase vacuolar pump. The subunit D was confirmed in this complex by coimmunoprecipitation investigations and it was found to colocalize with the receptor. The subunit D was also shown to be overexpressed by Western blot, RT-PCR and immunofluorescence analyses. Immunoprecipitation and immunofluorescence also revealed that E5 oncoprotein was bound to the subunit D. Conclusion For the first time, a tri-component complex composed of E5/PDGF?R/subunit D has been documented in vivo. Previous in vitro studies have shown that the BPV-2 E5 oncoprotein binds to the proteolipid c ring of the V0-ATPase sector. We suggest that the E5/PDGF?R/subunit D complex may perturb proteostasis, organelle and cytosol homeostasis, which can result in altered protein degradation and in autophagic responses. PMID:24586417

Roperto, Sante; Russo, Valeria; Borzacchiello, Giuseppe; Urraro, Chiara; Luca, Roberta; Esposito, Iolanda; Riccardi, Marita Georgia; Raso, Cinzia; Gaspari, Marco; Ceccarelli, Dora Maria; Galasso, Rocco; Roperto, Franco

2014-01-01

248

Real-time DNA binding measurements of the ETS1 recombinant oncoproteins reveal significant kinetic differences between the p42 and p51 isoforms.  

PubMed Central

The sequence-specific DNA binding of recombinant p42 and p51 ETS1 oncoprotein was examined quantitatively to determine whether the loss of the Exon VII phosphorylation domain in p42 ETS1 or the phosphorylation of expressed Exon VII in p51 ETS1 had an effect on DNA binding activity. The kinetics of sequence-specific DNA binding was measured using real-time changes in surface plasmon resonance with BIAcore (registered trademark, Pharmacia Biosensor) technology. The real-time binding of p42 and p51 ETS1 displayed significant differences in kinetic behavior. p51 ETS1 is characterized by a fast initial binding and conversion to a stable complex, whereas p42 ETS1 exhibits a slow initial binding and conversion to a stable complex. All of the p51 ETS1 DNA binding states are characterized by rapid turnover, whereas the p42 ETS1 DNA binding states are 4-20 times more stable. A model describing these kinetic steps is presented. Stoichiometric titrations of either p42 or p51 ETS1 with specific oligonucleotides show 1:1 complex formation. The DNA sequence specificity of the p42 and p51 ETS1 as determined by mutational analysis was similar. The in vitro phosphorylation of p51 ETS1 by CAM kinase II obliterates its binding to specific DNA, suggesting that the regulation of p51 ETS1 sequence-specific DNA binding occurs through phosphorylation by a calcium-dependent second messenger. The p42 ETS1 lacks this regulatory domain (Exon VII), and binding to its specific DNA sequence is not sensitive to calcium signaling. PMID:8003962

Fisher, R. J.; Fivash, M.; Casas-Finet, J.; Erickson, J. W.; Kondoh, A.; Bladen, S. V.; Fisher, C.; Watson, D. K.; Papas, T.

1994-01-01

249

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

PubMed Central

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

Stik, Gregoire; Dambrine, Ginette; Pfeffer, Sebastien

2013-01-01

250

Discovery of multiple interacting partners of gankyrin, a proteasomal chaperone and an oncoprotein--evidence for a common hot spot site at the interface and its functional relevance.  

PubMed

Gankyrin, a non-ATPase component of the proteasome and a chaperone of proteasome assembly, is also an oncoprotein. Gankyrin regulates a variety of oncogenic signaling pathways in cancer cells and accelerates degradation of tumor suppressor proteins p53 and Rb. Therefore gankyrin may be a unique hub integrating signaling networks with the degradation pathway. To identify new interactions that may be crucial in consolidating its role as an oncogenic hub, crystal structure of gankyrin-proteasome ATPase complex was used to predict novel interacting partners. EEVD, a four amino acid linear sequence seems a hot spot site at this interface. By searching for EEVD in exposed regions of human proteins in PDB database, we predicted 34 novel interactions. Eight proteins were tested and seven of them were found to interact with gankyrin. Affinity of four interactions is high enough for endogenous detection. Others require gankyrin overexpression in HEK 293 cells or occur endogenously in breast cancer cell line- MDA-MB-435, reflecting lower affinity or presence of a deregulated network. Mutagenesis and peptide inhibition confirm that EEVD is the common hot spot site at these interfaces and therefore a potential polypharmacological drug target. In MDA-MB-231 cells in which the endogenous CLIC1 is silenced, trans-expression of Wt protein (CLIC1_EEVD) and not the hot spot site mutant (CLIC1_AAVA) resulted in significant rescue of the migratory potential. Our approach can be extended to identify novel functionally relevant protein-protein interactions, in expansion of oncogenic networks and in identifying potential therapeutic targets. PMID:24338975

Nanaware, Padma P; Ramteke, Manoj P; Somavarapu, Arun K; Venkatraman, Prasanna

2014-07-01

251

Cyclin E2, a novel human G1 cyclin and activating partner of CDK2 and CDK3, is induced by viral oncoproteins  

E-print Network

activity by forming a ternary p21-cyclin D-CDK4 complex. The INK4 family inhibitors which include four by activating CDK2, and abnormally high levels of cyclin E expression have frequently been observed in human-dependent kinases (CDKs) which consist of an activating subunit, a cyclin, and a catalytic subunit, a CDK

Xiong, Yue

252

Safety and Efficacy of Adalimumab (D2E7) in Crohn's Disease Patients with an Attenuated Response to Infliximab  

Microsoft Academic Search

OBJECTIVES:Although infliximab is highly effective in the treatment of Crohn's disease (CD), attenuated response to infliximab may develop over time in a subgroup of patients. The aim of our study was to examine the safety and efficacy of adalimumab (D2E7), a fully humanized anti-TNF-? Ab, in CD patients who had experienced an attenuated response to infliximab.METHODS:Fifteen patients with active CD

Konstantinos A. Papadakis; Omid A. Shaye; Eric A. Vasiliauskas; Andrew Ippoliti; Marla C. Dubinsky; Jaime Birt; Jane Paavola; Susie K. Lee; Joanne Price; Stephan R. Targan; Maria T. Abreu

2005-01-01

253

Protein Tyrosine Phosphatase 1B Antagonizes Signalling by Oncoprotein Tyrosine Kinase p210 bcr-abl In Vivo  

PubMed Central

The p210 bcr-abl protein tyrosine kinase (PTK) appears to be directly responsible for the initial manifestations of chronic myelogenous leukemia (CML). In contrast to the extensive characterization of the PTK and its effects on cell function, relatively little is known about the nature of the protein tyrosine phosphatases (PTPs) that may modulate p210 bcr-abl-induced signalling. In this study, we have demonstrated that expression of PTP1B is enhanced specifically in various cells expressing p210 bcr-abl, including a cell line derived from a patient with CML. This effect on expression of PTP1B required the kinase activity of p210 bcr-abl and occurred rapidly, concomitant with maximal activation of a temperature-sensitive mutant of the PTK. The effect is apparently specific for PTP1B since, among several PTPs tested, we detected no change in the levels of TCPTP, the closest relative of PTP1B. We have developed a strategy for identification of physiological substrates of individual PTPs which utilizes substrate-trapping mutant forms of the enzymes that retain the ability to bind to substrate but fail to catalyze efficient dephosphorylation. We have observed association between a substrate-trapping mutant of PTP1B (PTP1B-D181A) and p210 bcr-abl, but not v-Abl, in a cellular context. Consistent with the trapping data, we observed dephosphorylation of p210 bcr-abl, but not v-Abl, by PTP1B in vivo. We have demonstrated that PTP1B inhibited binding of the adapter protein Grb2 to p210 bcr-abl and suppressed p210 bcr-abl-induced transcriptional activation that is dependent on Ras. These results illustrate selectivity in the effects of PTPs in a cellular context and suggest that PTP1B may function as a specific, negative regulator of p210 bcr-abl signalling in vivo. PMID:9566916

LaMontagne, Kenneth R.; Flint, Andrew J.; Franza, B. Robert; Pendergast, Ann Marie; Tonks, Nicholas K.

1998-01-01

254

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

PubMed

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

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

2013-04-25

255

TARGETING THE eIF4A RNA HELICASE BLOCKS TRANSLATION OF THE MUC1-C ONCOPROTEIN  

PubMed Central

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

Jin, Caining; Rajabi, Hasan; Rodrigo, Christina M.; Porco, John A.; Kufe, Donald

2012-01-01

256

Maf nuclear oncoprotein recognizes sequences related to an AP-1 site and forms heterodimers with both Fos and Jun.  

PubMed Central

The v-maf oncogene, identified from AS42 avian retrovirus, encodes a nuclear bZip protein. To elucidate the molecular mechanism of cell transformation induced by this oncogene, we determined the specific binding sequences of its product. Maf protein recognized two types of relatively long palindromic consensus sequences, TGCTGACTCAGCA and TGCTGACGTCAGCA, at roughly equal efficiency. The middle parts of these Maf-binding sequences completely match with two binding sequences for AP-1 transcription factor, i.e., phorbol 12-O-tetradecanoate-13-acetate (TPA)-responsive element (TRE) and cyclic AMP responsive element, suggesting partial overlapping of the target genes for Maf and AP-1. Furthermore, Maf efficiently formed heterodimers with the components of AP-1, Fos and Jun, through their leucine zipper structures, and these heterodimers show binding specificities distinct from those for Maf-Maf and Jun-Jun homodimers. Thus, a multiple combination of the dimers should generate a greatly expanded repertoire of transcriptional regulatory potential. DNA data base search for the Maf-binding consensus sequences suggested that some of the TRE-like cis elements reported previously may actually be the targets for Maf family proteins or their heterodimers with other bZip proteins. Images PMID:8264639

Kataoka, K; Noda, M; Nishizawa, M

1994-01-01

257

The PIM family of oncoproteins: Small kinases with huge implications in myeloid leukemogenesis and as therapeutic targets  

PubMed Central

PIM kinases are a family of serine/threonine kinases involved in cell survival and proliferation. There is significant structural similarity between the three PIM kinases (PIM1, PIM2 and PIM3) and few amino acid differences. Although, several studies have specifically monitored the role of PIM1 in tumorigenesis, much less is known about PIM2 and PIM3. Therefore, in this study we have used in vitro cell culture models and in vivo bone marrow infection/transplantation to assess the comparative signaling and oncogenic potential of each of the three PIM kinases. All three PIM kinases were able to protect FL5.12 cells from IL-3 withdrawal induced death. Interestingly, the downstream signaling cascades were indistinguishable between the three kinases. Transplantation of murine bone marrow co-expressing MYC and PIM1, PIM2 or PIM3 caused rapid and uniformly lethal myeloid leukemia. De-induction of MYC 18 days following transplantation significantly increased the survival of mice, even with continual expression of PIM kinases. Alternatively, mice treated at the pre-leukemic stage with a PIM kinase inhibitor increased the lifespan of the mice, even with continual expression of the MYC transgene. These data demonstrate the role of PIM kinases in driving myeloid leukemia, and as candidate molecules for therapy against human malignancies. PMID:25238262

Shah, Parag P.; Mims, Alice S.; Lockwood, William W.; Kraft, Andrew S.; Beverly, Levi J.

2014-01-01

258

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

2012-12-17

259

Translational fusion and redirection to thylakoid lumen as strategies to enhance accumulation of human papillomavirus e7 antigen in tobacco chloroplasts.  

PubMed

Human papillomavirus (HPV) is the causal agent of cervical cancer, one of the most common causes of death in women worldwide, and its E7 antigen is the major candidate for a therapeutic vaccine. The large scale production of E7 by molecular farming that would lead to the development of a safe and inexpensive vaccine is impaired by its low accumulation level in the plant cell. To enhance antigen production in the plastids, two alternative strategies were carried out: the expression of E7 as a translational fusion to ?-glucuronidase enzyme and redirection of E7 into the thylakoid lumen. The use of the ?-glucuronidase as a partner protein turned out to be a successful strategy, antigen expression levels were enhanced between 30 and 40 times relative to unfused E7. Moreover, best accumulation, albeit at a high metabolic cost that compromised biomass production, was obtained redirecting E7 into the thylakoid lumen by the incorporation of the N-terminal transit peptide, Str. Following this approach lumenal E7 production exceeded the stromal by two orders of magnitude. Our results highlight the relevance of exploring different strategies to improve recombinant protein stability for certain transgenes in order to exploit potential advantages of recombinant protein accumulation in chloroplasts. PMID:24981330

Morgenfeld, Mauro; Lentz, Ezequiel; Segretin, María Eugenia; Alfano, E Federico; Bravo-Almonacid, Fernando

2014-11-01

260

?E?7 integrin interaction with E-cadherin promotes antitumor CTL activity by triggering lytic granule polarization and exocytosis  

PubMed Central

Various T cell adhesion molecules and their cognate receptors on target cells promote T cell receptor (TCR)–mediated cell killing. In this report, we demonstrate that the interaction of epithelial cell marker E-cadherin with integrin ?E(CD103)?7, often expressed by tumor-infiltrating lymphocytes (TILs), plays a major role in effective tumor cell lysis. Indeed, we found that although tumor-specific CD103+ TIL-derived cytotoxic T lymphocyte (CTL) clones are able to kill E-cadherin+/intercellular adhesion molecule 1? autologous tumor cells, CD103? peripheral blood lymphocyte (PBL)-derived counterparts are inefficient. This cell killing is abrogated after treatment of the TIL clones with a blocking anti-CD103 monoclonal antibody or after targeting E-cadherin in the tumor using ribonucleic acid interference. Confocal microscopy analysis also demonstrated that ?E?7 is recruited at the immunological synapse and that its interaction with E-cadherin is required for cytolytic granule polarization and subsequent exocytosis. Moreover, we report that the CD103? profile, frequently observed in PBL-derived CTL clones and associated with poor cytotoxicity against the cognate tumor, is up-regulated upon TCR engagement and transforming growth factor ?1 treatment, resulting in strong potentiation of antitumor lytic function. Thus, CD8+/CD103+ tumor-reactive T lymphocytes infiltrating epithelial tumors most likely play a major role in antitumor cytotoxic response through ?E?7–E-cadherin interactions. PMID:17325197

Floc'h, Audrey Le; Jalil, Abdelali; Vergnon, Isabelle; Chansac, Beatrice Le Maux; Lazar, Vladimir; Bismuth, Georges; Chouaib, Salem; Mami-Chouaib, Fathia

2007-01-01

261

Down-regulation of HPV18 E6, E7, or VEGF expression attenuates malignant biological behavior of human cervical cancer cells.  

PubMed

To investigate the effect of down-regulation of VEGF (vascular endothelial growth factor) and HPV18 E6/E7 by hairpin RNA (shRNA) on cell proliferation, apoptosis, migration, invasion, and adhesion abilities of cervical carcinoma cells, recombinant plasmids including pS-E6 shRNA, pS-E7 shRNA, and pS-VEGF shRNA were constructed and transfected into HeLa cells. The levels of E6 mRNA, E7 mRNA, or VEGF mRNA were significantly reduced after transfection of pS-E6 shRNA (76.0%), pS-E7 shRNA (74.4%), and pS-VEGF shRNA (46.7%). VEGF expression was down-regulated by pS-E6 shRNA (55.1%) and pS-E7 shRNA (46.6%). The apoptosis of HeLa cells was increased, and the proliferation, invasion, and adhesion abilities were decreased significantly. For in vivo study, cancer cells that stably expressed the plasmids were cultured. Cells were transplanted subcutaneously into nude mice to establish xenograft tumor model. Finally, expression of E6 shRNA, E7 shRNA, and VEGF shRNA in cancer cells led to inhibition of the growth of xenograft. Hence, RNA interference could effectively suppress the expression of HPV18 E6/E7 and VEGF in human cervical cancer cells. This suppression attenuates malignant biological behavior of human cervical cancer cells. RNA interference of HPV E6/E7 or VEGF expression implies an effective anti-cervical cancer strategy. PMID:21222176

Chen, Li; Wu, Yuan-Yuan; Liu, Peigen; Wang, Jianli; Wang, Guilan; Qin, Jin; Zhou, Jiaming; Zhu, Jianwei

2011-12-01

262

Role of the Retinoblastoma Pathway in Senescence Triggered by Repression of the Human Papillomavirus E7 Protein in Cervical Carcinoma Cells  

Microsoft Academic Search

Repression of the endogenous human papillomavirus (HPV) type 18 E7 gene in HeLa cervical carcinoma cells by the bovine papillomavirus E2 transcription factor activates the retinoblastoma (Rb) pathway and in- duces cells to undergo senescence. To determine whether activation of the Rb pathway is responsible for senescence in response to HPV18 E7 repression, we tested the ability of wild-type and

Amanda Psyrri; Rosa Anna DeFilippis; Anne P. B. Edwards; Kristin E. Yates; Laertes Manuelidis; Daniel DiMaio

2004-01-01

263

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

264

Oncoprotein protein kinase antibody kit  

DOEpatents

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

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

2008-12-23

265

The E7 Open Reading Frame Acts in cis and in trans To Mediate Differentiation-Dependent Activities in the Human Papillomavirus Type 16 Life Cycle?†  

PubMed Central

Human papillomaviruses (HPVs) are the causative agents of several important genital and other mucosal cancers. The HPV16 E7 gene encodes a viral oncogene that is necessary for the continued growth of cancer cells, but its role in the normal, differentiation-dependent life cycle of the virus is not fully understood. The function of E7 in the viral life cycle was examined using a series of mutations of E7 created in the context of the complete HPV16 genome. The effect of these E7 mutations on key events of the viral life cycle, including immortalization, episomal maintenance, late promoter activation, and infectious virion synthesis, was examined. Our studies show that the pRb binding domain is indispensable for early viral activities, whereas the C-terminal zinc finger domain contributed primarily to very late events. Mutations of the casein kinase II phosphorylation site caused a complex phenotype involving both the function of E7 protein and a cis element necessary for the activation of the late promoter, identifying for the first time a promoter element important for late promoter function in the context of the viral genome. All mutant genomes tested showed reduced viral titers following growth in organotypic raft cultures. These studies clarify the role of E7 as a regulator of late events in the differentiation-dependent HPV life cycle. PMID:21697473

Bodily, Jason M.; Mehta, Kavi P. M.; Cruz, Linda; Meyers, Craig; Laimins, Laimonis A.

2011-01-01

266

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

267

A new insight into the zinc-dependent DNA-cleavage by the colicin E7 nuclease: a crystallographic and computational study.  

PubMed

The nuclease domain of colicin E7 metallonuclease (NColE7) contains its active centre at the C-terminus. The mutant ?N4-NColE7-C* - where the four N-terminal residues including the positively charged K446, R447 and K449 are replaced with eight residues from the GST tag - is catalytically inactive. The crystal structure of this mutant demonstrates that its overall fold is very similar to that of the native NColE7 structure. This implicates the stabilizing effect of the remaining N-terminal sequence on the structure of the C-terminal catalytic site and the essential role of the deleted residues in the mechanism of the catalyzed reaction. Complementary QM/MM calculations on the protein-DNA complexes support the less favourable cleavage by the mutant protein than by NColE7. Furthermore, a water molecule as a possible ligand for the Zn(2+)-ion is proposed to play a role in the catalytic process. These results suggest that the mechanism of the Zn(2+)-containing HNH nucleases needs to be further studied and discussed. PMID:25179124

Czene, Anikó; Tóth, Eszter; Németh, Eszter; Otten, Harm; Poulsen, Jens-Christian N; Christensen, Hans E M; Rulíšek, Lubomír; Nagata, Kyosuke; Larsen, Sine; Gyurcsik, Béla

2014-10-22

268

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. PMID:23341863

Juarez, Victoria; Pasolli, H Amalia; Hellwig, Andrea; Garbi, Natalio; Arregui, Angel Cid

2012-01-01

269

2E7 ENGINEERING AND THE ENVIRONMENT [5 credits] Lecturer(s): Assistant Prof. Sarah McCormack (mccorms1@tcd.ie)  

E-print Network

and human environmental disturbances: acid rain, greenhouse gases, carbon cycle, climate change Introduction2E7 ENGINEERING AND THE ENVIRONMENT [5 credits] Lecturer(s): Assistant Prof. Sarah Mc processes which affect the environment and the ways in which these impacts may be assessed; to develop

O'Mahony, Donal E.

270

Explicit computations of low lying eigenfunctions for the quantum trigonometric Calogero-Sutherland model related to the exceptional algebra E7  

E-print Network

In the previous paper math-ph/0507015 we have studied the characters and Clebsch-Gordan series for the exceptional Lie algebra E7 by relating them to the quantum trigonometric Calogero-Sutherland Hamiltonian with coupling constant K=1. Now we extend that approach to the case of general K.

J. Fernandez Nunez; W. Garcia Fuertes; A. M. Perelomov

2006-04-25

271

Successful Rechallenge with Imatinib in a Patient with Chronic Myeloid Leukemia Who Previously Experienced Imatinib Mesylate Induced Pneumonitis  

PubMed Central

Imatinib mesylate is a targeted therapy that acts by inhibiting tyrosine kinase of the bcr-abl fusion oncoprotein, which is specific to chronic myeloid leukemia (CML), and the c-transmembrane receptor, which is specific to gastrointestinal stromal tumors. Interstitial pneumonitis is a rare adverse event of imatinib therapy. It is clinically difficult to distinguish from infectious pneumonia, which can frequently occur due to the underlying disease. The standard treatment for imatinib-induced pneumonitis is to discontinue the medication and optionally administer corticosteroids. However, there are a few cases of successful retrial with imatinib. We describe a case of successful rechallenge of imatinib in a patient with imatinib-induced interstitial pneumonitis and CML without a recurrence of the underlying disease after 3 months of follow-up. PMID:24416057

Go, Seong Woo; Kim, Boo Kyeong; Lee, Sung Hak; Kim, Tae-Jung; Huh, Joo Yeon; Lee, Jong Min; Hah, Jick Hwan; Kim, Dong Whi; Cho, Min Jung; Kim, Tae Wan

2013-01-01

272

Interaction of the E1A Oncoprotein with Yak1p, a Novel Regulator of Yeast Pseudohyphal Differentiation, and Related Mammalian Kinases  

PubMed Central

The C-terminal portion of adenovirus E1A suppresses ras-induced metastasis and tumorigenicity in mammalian cells; however, little is known about the mechanisms by which this occurs. In the simple eukaryote Saccharomyces cerevisiae, Ras2p, the homolog of mammalian h-ras, regulates mitogen-activated protein kinase (MAPK) and cyclic AMP-dependent protein kinase A (cAMP/PKA) signaling pathways to control differentiation from the yeast form to the pseudohyphal form. When expressed in yeast, the C-terminal region of E1A induced pseudohyphal differentiation, and this was independent of both the MAPK and cAMP/PKA signaling pathways. Using the yeast two-hybrid system, we identified an interaction between the C-terminal region of E1A and Yak1p, a yeast dual-specificity serine/threonine protein kinase that functions as a negative regulator of growth. E1A also physically interacts with Dyrk1A and Dyrk1B, two mammalian homologs of Yak1p, and stimulates their kinase activity in vitro. We further demonstrate that Yak1p is required in yeast to mediate pseudohyphal differentiation induced by Ras2p-regulated signaling pathways. However, pseudohyphal differentiation induced by the C-terminal region of E1A is largely independent of Yak1p. These data suggest that mammalian Yak1p-related kinases may be targeted by the E1A oncogene to modulate cell growth. PMID:11251081

Zhang, Zhiying; Smith, M. Mitchell; Mymryk, Joe S.

2001-01-01

273

Identification of antibodies against human papillomavirus type 16 E4 and E7 proteins in sera of patients with cervical neoplasias.  

PubMed

Sera from 35 women (patients with various clinical diagnosis: cervical dysplasia, benign and malignant tumors of the uterine cervix) were tested by immunodot blot for the presence of antibodies to E4 and E7 HPV16 proteins. A number of 26 sera displayed positivities for at least one antibody type. The mean absorbance for anti-E antibody in positive cases was higher in cancer patients (15 from 16 sera) as compared with other diagnoses (2 from 5 in dysplasia or one from 4 in uterine fibroma). Interestingly, most sera were reactive for both proteins. The high prevalence rates and high absorbance values for HPV16 E7 antibodies in association with malignant transformation suggest that the detection of these antibodies may be a useful diagnostic aid for cervical cancer--associated HPV16. PMID:7619739

Stoian, M; Repanovici, R

1994-01-01

274

The E2F5 repressor is an activator of E6/E7 transcription and of the S-phase entry in HPV18-associated cells.  

PubMed

High-risk papillomavirus type 18 (HPV18) is one of the less represented HPV types in low-grade lesions of the anogenital tract, whereas it occupies the second place in cervical cancer, where it can be found in 16% of the cases worldwide, after HPV16 present in 54% of them. These epidemiological data indicate that HPV18 infection is more prone to carcinogenic progression. The main oncogenic proteins, E6 and E7 of HPV18, are functionally comparable to the homologous proteins of the other high-risk viruses, including HPV16. In this work, we investigated the possibility that the higher oncogenic potential of HPV18 might be due to transcriptional regulation of the E6/E7 oncogenes. By comparing the E6/E7 promoter and enhancer sequences of the mucosal HPV genomes, we identified E2F binding sites specific for HPV18. The E2F family of transcription factors contains activators (E2F1-3) and repressors (E2F4-8) that regulate the transcription of S-phase and mitotic genes and thereby have a crucial role in cell-cycle progression. Surprisingly, we identified E2F5 as a direct activator of HPV18 E6/E7 transcription by sequential silencing of E2F members in HeLa cells. In addition, we could show that E2F5 positively regulates S-phase entry in HeLa cells and that this activation of the cell cycle by a member of the E2F repressor family is specific for HPV18-expressing cells. Diverting the function of E2F5 from a cell-cycle repressor into an activator might contribute to the higher oncogenic potential of HPV18 when compared with other high-risk HPV types. PMID:20639900

Teissier, S; Pang, C L; Thierry, F

2010-09-01

275

Targeting the Human Papillomavirus E6 and E7 Oncogenes through Expression of the Bovine Papillomavirus Type 1 E2 Protein Stimulates Cellular Motility?†  

PubMed Central

Expression of the high-risk human papillomavirus (HPV) E6 and E7 oncogenes is essential for the initiation and maintenance of cervical cancer. The repression of both was previously shown to result in activation of their respective tumor suppressor targets, p53 and pRb, and subsequent senescence induction in cervical cancer cells. Consequently, viral oncogene suppression is a promising approach for the treatment of HPV-positive tumors. One well-established method of E6/E7 repression involves the reexpression of the viral E2 protein which is usually deleted in HPV-positive cancer cells. Here, we show that, surprisingly, bovine papillomavirus type 1 (BPV1) E2 but not RNA interference-mediated E6/E7 repression in HPV-positive cervical cancer cells stimulates cellular motility and invasion. Migration correlated with the dynamic formation of cellular protrusions and was dependent upon cell-to-cell contact. While E2-expressing migratory cells were senescent, migration was not a general feature of cellular senescence or cell cycle arrest and was specifically observed in HPV-positive cervical cancer cells. Interestingly, E2-expressing cells not only were themselves motile but also conferred increased motility to admixed HeLa cervical cancer cells. Together, our data suggest that repression of the viral oncogenes by E2 stimulates the motility of E6/E7-targeted cells as well as adjacent nontargeted cancer cells, thus raising the possibility that E2 expression may unfavorably increase the local invasiveness of HPV-positive tumors. PMID:21835799

Morrison, Monique A.; Morreale, Richard J.; Akunuru, Shailaja; Kofron, Matthew; Zheng, Yi; Wells, Susanne I.

2011-01-01

276

The Human DEK ProtoOncogene Is a Senescence Inhibitor and an Upregulated Target of High-Risk Human Papillomavirus E7  

Microsoft Academic Search

The human DEK proto-oncogene is a nucleic acid binding protein with suspected roles in human carcino- genesis, autoimmune disease, and viral infection. Intracellular DEK functions, however, are poorly understood. In papillomavirus-positive cervical cancer cells, downregulation of viral E6\\/E7 oncogene expression results in cellular senescence. We report here the specific repression of DEK message and protein levels in senescing human papillomavirus

Trisha M. Wise-Draper; Hillary V. Allen; Megan N. Thobe; Elizabeth E. Jones; Kristen B. Habash; Karl Munger; Susanne I. Wells

2005-01-01

277

Lymphoproliferative Responses to Human Papillomavirus (HPV) Type 16 Proteins E6 and E7: Outcome of HPV Infection and Associated Neoplasia  

Microsoft Academic Search

Background: Infection with human papillomavirus (HPV) type 16 (HPV16) is a major cause of high-grade cervical intraepithelial neoplasia (CIN). Experiments were planned to evaluate the role of cell-mediated immunity (e.g., lympho- cyte proliferation) against HPV in the natural history of HPV-associated neoplasia and to identify antigenic se- quences of the HPV16 proteins E6 and E7 against which an immune response

Anna S. Kadish; Gloria Y. F. Ho; Robert D. Burk; Yuexian Wang; Seymour L. Romney; Richard Ledwidge; Ruth H. Angeletti

1997-01-01

278

Targeted expression of the E6 and E7 oncogenes of human papillomavirus type 16 in the epidermis of transgenic mice elicits generalized epidermal hyperplasia involving autocrine factors.  

PubMed Central

The E6 and E7 early genes of human papillomavirus type 16 have been shown in vitro to play a central role in the transforming capability of this virus. To explore their effects on differentiating epithelial cells in vivo, we used a bovine cytokeratin 10 (K10) promoter to target the expression of E6 and E7 to the suprabasal layers of the epidermis of transgenic mice. In two different lines of mice efficiently expressing the transgene, animals displayed generalized epidermal hyperplasia, hyperkeratosis and parakeratosis in the skin and the forestomach, both known to be sites of K10 expression. Northern (RNA) blot analysis revealed high levels of E6 and E7 transcripts, and in situ hybridizations localized these transcripts to the suprabasal strata of epidermis. In vivo labeling of proliferating cells showed two distinct effects of E6 and E7 expression in the epidermis: (i) an increase in the number of growing cells in the undifferentiated basal layer and (ii) abnormal proliferation of differentiated cells in the suprabasal strata. The expression of c-myc in the skin of transgenics was higher than that in control animals. The induction of c-myc transcription by topical application of tetradecanoyl phorbol acetate was prevented by simultaneous treatment with transforming growth factor beta 1 in nontransgenic skin but not in transgenic skin. In addition, transforming growth factor alpha was found to be overexpressed in the suprabasal layers of the transgenic epidermis. These findings suggest that autocrine mechanisms are involved in the development and maintenance of epidermal hyperplasia. Animals of both lines developed papillomas in skin sites exposed to mechanical irritation and wounding, suggesting that secondary events are necessary for progression to neoplasia. Collectively, these results provide new insights into the tumor promoter activities of human papillomavirus type 16 in epithelial cells in vivo. Images PMID:7969162

Auewarakul, P; Gissmann, L; Cid-Arregui, A

1994-01-01

279

Transcription of Human Papillomavirus Type 16 Early Genes in a Cervical Cancer and a Cancer-Derived Cell Line and Identification of the E7 Protein  

Microsoft Academic Search

Human papillomavirus type 16 DNA and RNA were characterized in the cervical cancer-derived CaSki cell line, which contains only integrated DNA, and in a cervical cancer, which contains predominantly plasmid DNA. In both, a major RNA can code for the early open reading frame E7 and a minor one can code for E6. The cervical cancer, but not the CaSki

David Smotkin; Felix O. Wettstein

1986-01-01

280

Epstein-Barr virus oncoprotein LMP1 mediates survivin upregulation by p53 contributing to G1/S cell cycle progression in nasopharyngeal carcinoma  

PubMed Central

Latent membrane protein 1 (LMP1) is an important oncogenic protein encoded by Epstein-Barr virus (EBV) and plays an important role in the development of nasopharyngeal carcinoma (NPC). Our previous study has shown that p53 protein was accumulated and phosphorylated in NPC, implying its transcription factor activity in NPC tumorigenesis. However, the biological function and potential downstream target of p53 mediated by LMP1 in NPC remain unknown. In this study, we found that LMP1 simultaneously induced upregulation of both p53 and survivin at the protein level, as well as their phosphorylation. Knockdown of p53 by siRNA revealed that LMP1 increased survivin expression by p53 directly. Furthermore, we found that LMP1 upregulated survivin by p53 at the transcriptional level by increasing p53-mediated survivin promoter activity and DNA binding activity. Moreover, LMP1 induced the co-localization of p53 and survivin in the nucleus, conferring to their related functions in NPC tumorigenesis. We further found that p53 promoted G1/S cell cycle progression, but did not induce apoptosis in LMP1-positive NPC cells. Collectively, these findings suggest that p53 acting as a transcription factor promotes the transcriptional activity of survivin, and further increases its protein expression and phosphorylation in the regulation of LMP1, thus, leading to G1/S cell cycle progression with no effect on apoptosis in NPC tumorigenesis. PMID:22266808

GUO, LILI; TANG, MIN; YANG, LIFANG; XIAO, LANBO; BODE, ANN M.; LI, LILI; DONG, ZIGANG; CAO, YA

2012-01-01

281

The state of immortalized, transforming and suppressor genes in rat-cells, transfected by polyomavirus large-T and hpv18 e6+e7 genes.  

PubMed

Several novel cell clones (A1-A6) derived from the rat embryo fibroblasts immortalized by the polyoma virus T-antigen (LT) gene and transformed by HPV18 E6 and E7 genes were explored. Using E6 or E7 peptide antisera we detected E6 and E7 proteins with approximate molecular masses of 16 kDa and 20 kDa, respectively. Monoclonal antibody to p53 PAb421 but not PAb240 precipitated different but appreciable amounts of p53 protein in all cell clones, indicating that wild-type p53 is expressed in these cells. So expression of HPV18 E6 protein in cells does not always lead to a complete reduction in p53 levels. The quantity of p53 protein in cell clones did not correlate with the level of polyoma virus large T-antigen expression. Variations in levels of p53 protein in clones did not influence on such cell biological properties as anchorage-independence and tumorigenicity for nude mice which were similar in all cell clones. PMID:21597877

Komissarova, E; Soyfer, M; Pavlova, L; Kisseljov, F

1995-11-01

282

Notch1 signaling inhibits growth of EC109 esophageal carcinoma cells through downmodulation of HPV18 E6/E7 gene expression  

PubMed Central

Aim: To investigate the role of the Notch1 signaling pathway in growth arrest of an esophageal carcinoma cell line (EC109) in vitro and the mechanism involved. Methods: An intracellular domain of Notch1 (ICN) was transfected into cultured EC109 cells by lipofectamine transfection. Subsequently, the proliferation of the transfected cells was measured by an MTT assay. Cell cycle distribution was analyzed by flow cytometry. Human papillomavirus type 18 (HPV18) E6/E7 mRNA expression was detected by RT-PCR, and p53 protein expression was detected by Western blot. Results: Activation of Notch1 signaling resulted in inhibition of EC109 cell proliferation with the induction of G2/M arrest, downmodulation of HPV18 E6/E7 gene expression, and upregulation of p53 expression. Conclusion: Repression of HPV18 E6/E7 expression by Notch1 signaling results in the activation of p53-mediated pathways with concomitant growth suppression of HPV18-positive EC109 cells. PMID:19122673

Zhang, Ke-jie; Lu, Quan-yi; Niu, Xiao-qing; Zhang, Peng; Zhao, Jiang-ning; Wang, Zhao; Hu, Jia-sheng; Li, Pu; Liu, Wen-li

2009-01-01

283

MUC1-C oncoprotein activates ERK?C/EBP? signaling and induction of aldehyde dehydrogenase 1A1 in breast cancer cells.  

PubMed

Aldehyde dehydrogenase 1A1 (ALDH1A1) activity is used as a marker of breast cancer stem cells; however, little is known about the regulation of ALDH1A1 expression. Mucin 1 (MUC1) is a heterodimeric protein that is aberrantly overexpressed in most human breast cancers. In studies of breast cancer cells stably silenced for MUC1 or overexpressing the oncogenic MUC1-C subunit, we demonstrate that MUC1-C is sufficient for induction of MEK ? ERK signaling and that treatment with a MUC1-C inhibitor suppresses ERK activation. In turn, MUC1-C induces ERK-mediated phosphorylation and activation of the CCAAT/enhancer-binding protein ? (C/EBP?) transcription factor. The results further show that MUC1-C and C/EBP? form a complex on the ALDH1A1 gene promoter and activate ALDH1A1 gene transcription. MUC1-C-induced up-regulation of ALDH1A1 expression is associated with increases in ALDH activity and is detectable in stem-like cells when expanded as mammospheres. These findings demonstrate that MUC1-C (i) activates a previously unrecognized ERK?C/EBP??ALDH1A1 pathway, and (ii) promotes the induction of ALDH activity in breast cancer cells. PMID:24043631

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

2013-10-25

284

MUC1-C Oncoprotein Activates ERK->C/EBP? Signaling and Induction of Aldehyde Dehydrogenase 1A1 in Breast Cancer Cells*  

PubMed Central

Aldehyde dehydrogenase 1A1 (ALDH1A1) activity is used as a marker of breast cancer stem cells; however, little is known about the regulation of ALDH1A1 expression. Mucin 1 (MUC1) is a heterodimeric protein that is aberrantly overexpressed in most human breast cancers. In studies of breast cancer cells stably silenced for MUC1 or overexpressing the oncogenic MUC1-C subunit, we demonstrate that MUC1-C is sufficient for induction of MEK?ERK signaling and that treatment with a MUC1-C inhibitor suppresses ERK activation. In turn, MUC1-C induces ERK-mediated phosphorylation and activation of the CCAAT/enhancer-binding protein ? (C/EBP?) transcription factor. The results further show that MUC1-C and C/EBP? form a complex on the ALDH1A1 gene promoter and activate ALDH1A1 gene transcription. MUC1-C-induced up-regulation of ALDH1A1 expression is associated with increases in ALDH activity and is detectable in stem-like cells when expanded as mammospheres. These findings demonstrate that MUC1-C (i) activates a previously unrecognized ERK?C/EBP??ALDH1A1 pathway, and (ii) promotes the induction of ALDH activity in breast cancer cells. PMID:24043631

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

2013-01-01

285

Interleukin-21 regulates expression of key Epstein-Barr virus oncoproteins, EBNA2 and LMP1, in infected human B cells  

SciTech Connect

Epstein-Barr virus (EBV) persists for the life of the host by accessing the long-lived memory B cell pool. It has been proposed that EBV uses different combinations of viral proteins, known as latency types, to drive infected B cells to make the transition from resting B cells to memory cells. This process is normally antigen-driven. A major unresolved question is what factors coordinate expression of EBV latency proteins. We have recently described novel type III latency EBV{sup +} B cell lines (OCI-BCLs) that were induced to differentiate into late plasmablasts/early plasma cells in culture with interleukin-21 (IL-21), mimicking normal B cell development. The objective of this study was to determine whether IL-21-mediated signals also regulate the expression of key EBV latent proteins during this window of development. Here we show that IL-21-reduced gene and protein expression of growth-transforming EBV nuclear antigen 2 (EBNA2) in OCI-BCLs. By contrast, the expression of CD40-like, latent membrane protein 1 (LMP1) strongly increased in these cells suggesting an EBNA2-independent mode of regulation. Same results were also observed in Burkitt's lymphoma line Jijoye and B95-8 transformed lymphoblastoid cell lines. The effect of IL-21 on EBNA2 and LMP1 expression was attenuated by a pharmacological JAK inhibitor indicating involvement of JAK/STAT signalling in this process. Our study also shows that IL-21 induced transcription of ebna1 from the viral Q promoter (Qp)

Konforte, Danijela [Division of Stem Cell and Developmental Biology, Princess Margaret Hospital, Ontario Cancer Institute, University Health Network, Toronto, M5G 2M9 (Canada); Department of Immunology, University of Toronto, Toronto, M5S 1A8 (Canada)], E-mail: danijela.konforte@utoronto.ca; Simard, Nathalie; Paige, Christopher J. [Division of Stem Cell and Developmental Biology, Princess Margaret Hospital, Ontario Cancer Institute, University Health Network, Toronto, M5G 2M9 (Canada); Department of Immunology, University of Toronto, Toronto, M5S 1A8 (Canada)

2008-04-25

286

The oncoprotein HBXIP uses two pathways to up-regulate S100A4 in promotion of growth and migration of breast cancer cells.  

PubMed

We have reported that hepatitis B X-interacting protein (HBXIP) promotes the proliferation and migration of breast cancer cells. However, the underlying mechanism is poorly understood. In this study, we report that HBXIP works in the event through up-regulating S100A4. We observed that HBXIP expression was positively correlated to that of S100A4 in 87 clinical breast cancer tissue samples. Then, we identified that HBXIP was able to up-regulate S100A4 expression in breast cancer cells. Notably, we observed the HBXIP nuclear localization, implying that HBXIP may be associated with the promoter of S100A4. Chromatin immunoprecipitation assay (ChIP) and electrophoretic mobility shift assay (EMSA) showed that HBXIP was able to bind to the nucleotides +200~+239 region of S100A4 promoter, containing two putative recognition motif of transcription factor STAT4 and GR?. It suggests that HBXIP is able to activate S100A4 promoter via interacting with STAT4 in breast cancer cells, leading to the up-regulation of S100A4. In addition, we identified another pathway of S100A4 up-regulation mediated by HBXIP. We found that HBXIP activated the PTEN/PI3K/AKT signaling by inducing DNA methylation of PTEN, which subsequently boosted S100A4 expression. In function, we demonstrated that HBXIP enhanced the growth or migration of breast cancer cells through S100A4 in vivo and in vitro. Collectively, we conclude that HBXIP up-regulates S100A4 through activating S100A4 promoter involving STAT4 and inducing PTEN/PI3K/AKT signaling to promote growth and migration of breast cancer cells. Our finding provides new insight into the mechanism of HBXIP in promotion of the development of breast cancer. PMID:22740693

Liu, Shuangping; Li, Leilei; Zhang, Yingyi; Zhang, Yiwen; Zhao, Yu; You, Xiaona; Lin, Zhenhua; Zhang, Xiaodong; Ye, Lihong

2012-08-31

287

Prognostic Value of DNA and mRNA E6/E7 of Human Papillomavirus in the Evolution of Cervical Intraepithelial Neoplasia Grade 2  

PubMed Central

OBJECTIVE This study aimed at evaluating whether human papillomavirus (HPV) groups and E6/E7 mRNA of HPV 16, 18, 31, 33, and 45 are prognostic of cervical intraepithelial neoplasia (CIN) 2 outcome in women with a cervical smear showing a low-grade squamous intraepithelial lesion (LSIL). METHODS This cohort study included women with biopsy-confirmed CIN 2 who were followed up for 12 months, with cervical smear and colposcopy performed every three months. RESULTS Women with a negative or low-risk HPV status showed 100% CIN 2 regression. The CIN 2 regression rates at the 12-month follow-up were 69.4% for women with alpha-9 HPV versus 91.7% for other HPV species or HPV-negative status (P < 0.05). For women with HPV 16, the CIN 2 regression rate at the 12-month follow-up was 61.4% versus 89.5% for other HPV types or HPV-negative status (P < 0.05). The CIN 2 regression rate was 68.3% for women who tested positive for HPV E6/E7 mRNA versus 82.0% for the negative results, but this difference was not statistically significant. CONCLUSIONS The expectant management for women with biopsy-confirmed CIN 2 and previous cytological tests showing LSIL exhibited a very high rate of spontaneous regression. HPV 16 is associated with a higher CIN 2 progression rate than other HPV infections. HPV E6/E7 mRNA is not a prognostic marker of the CIN 2 clinical outcome, although this analysis cannot be considered conclusive. Given the small sample size, this study could be considered a pilot for future larger studies on the role of predictive markers of CIN 2 evolution. PMID:24812482

Discacciati, Michelle G; da Silva, Ismael DCG; Villa, Luisa L; Reis, Leandro; Hayashi, Priscila; Costa, Maria C; Rabelo-Santos, Silvia H; Zeferino, Luiz C

2014-01-01

288

Diagnostic and prognostic validity of the human papillomavirus E6\\/E7 mRNA test in cervical cytological samples of HC2-positive patients  

Microsoft Academic Search

The study aimed to assess the clinical utility in identifying CIN2 or worse (CIN2+), of the Pretect HPV-Proofer test for E6\\/E7\\u000a mRNA detection in Hybrid Capture 2 (HC2)-positive patients, who underwent colposcopy. In particular, the study analyzed the\\u000a mRNA test performance as the third test in a subgroup of HC2+ patients with less severe than high-grade squamous intraepithelial\\u000a lesions (HSIL?).

Maria Benevolo; Irene Terrenato; Marcella Mottolese; Ferdinando Marandino; Mariantonia Carosi; Francesca Rollo; Livia Ronchetti; Paola Muti; Luciano Mariani; Stefano Sindico; Giuseppe Vocaturo; Amina Vocaturo

2011-01-01

289

Tricritical-like behavior of the nonlinear optical refraction at the nematic-isotropic transition in the E7 thermotropic liquid crystal.  

PubMed

We use Z-scan technique to investigate the nonlinear optical response of the thermotropic liquid crystal E7 in the neighborhood of the nematic-isotropic phase transition. The analysis of the data for the nonlinear optical birefringence is compatible with an effective critical exponent of the order parameter, ? = 0.28 ± 0.03, which is close to the classical value, ? = 0.25 , for a tricritical point. The nonlinear optical absorption in the nematic range depends on the geometrical configuration of the nematic director with respect to the polarization beam, and vanishes in the isotropic phase. PMID:22270454

Lenart, V M; Gómez, S L; Bechtold, I H; Figueiredo Neto, A M; Salinas, S R

2012-01-01

290

The oncoprotein v-Myb activates transcription of Gremlin 2 during in vitro differentiation of the chicken neural crest to melanoblasts.  

PubMed

The neural crest (NC) is a transient dynamic structure of ectodermal origin, found in early vertebrate embryos. The multipotential NC cells migrate along well defined routes, differentiate to various cell types including melanocytes and participate in the formation of various permanent tissues. As there is only limited information about the molecular mechanisms controlling early events in melanocyte specification and development, we exploited the AMV v-Myb transcriptional regulator, which directs differentiation of in vitro chicken NC cells to the melanocyte lineage. This activity is strictly dependent on v-Myb specifically binding to the Myb recognition DNA element (MRE). The two tamoxifen-inducible v-Myb alleles were constructed one which recognizes the MRE and one which does not. These were activated in ex ovo NC cells, and the expression profiles of resulting cells were analyzed using Affymetrix microarrays and RT-PCR. These approaches revealed up-regulation of the BMP antagonist Gremlin 2 mRNA, and down-regulation of mRNAs encoding several epithelial genes including KRT19 as very early events following the activation of melanocyte differentiation by v-Myb. The enforced v-Myb expression in neural tubes of chicken embryos resulted in detectable presence of Gremlin 2 mRNA. However, expression of Gremlin 2 in NC cells did not promote formation of melanocytes suggesting that Gremlin 2 is not the master regulator of melanocytic differentiation. PMID:24576577

Starostová, Michaela; Cermák, Vladimír; Dvo?áková, Marta; Karafiát, Vít; Kosla, Jan; Dvo?ák, Michal

2014-04-25

291

Fibroblast Growth Factor Receptor Signaling Dramatically Accelerates Tumorigenesis and Enhances Oncoprotein Translation in the Mouse Mammary Tumor Virus-Wnt-1 Mouse Model of Breast Cancer  

PubMed Central

Fibroblast growth factor (FGF) cooperates with the Wnt/?-catenin pathway to promote mammary tumorigenesis. To investigate the mechanisms involved in FGF/Wnt cooperation, we genetically engineered a model of inducible FGF receptor (iFGFR) signaling in the context of the well-established mouse mammary tumor virus–Wnt-1 transgenic mouse. In the bigenic mice, iFGFR1 activation dramatically enhanced mammary tumorigenesis. Expression microarray analysis did not show transcriptional enhancement of Wnt/?-catenin target genes but instead showed a translational gene signature that also correlated with elevated FGFR1 and FGFR2 in human breast cancer data sets. Additionally, iFGFR1 activation enhanced recruitment of RNA to polysomes, resulting in a marked increase in protein expression of several different Wnt/?-catenin target genes. FGF pathway activation stimulated extracellular signal-regulated kinase and the phosphorylation of key translation regulators both in vivo in the mouse model and in vitro in a human breast cancer cell line. Our results suggest that cooperation of the FGF and Wnt pathways in mammary tumorigenesis is based on the activation of protein translational pathways that result in, but are not limited to, increased expression of Wnt/?-catenin target genes (at the level of protein translation). Further, they reveal protein translation initiation factors as potential therapeutic targets for human breast cancers with alterations in FGF signaling. PMID:20501844

Pond, Adam C.; Herschkowitz, Jason I.; Schwertfeger, Kathryn L.; Welm, Bryan; Zhang, Yiqun; York, Brian; Cardiff, Robert D.; Hilsenbeck, Susan; Perou, Charles M.; Creighton, Chad J.; Lloyd, Richard E.; Rosen, Jeffrey M.

2010-01-01

292

Fibroblast growth factor receptor signaling dramatically accelerates tumorigenesis and enhances oncoprotein translation in the mouse mammary tumor virus-Wnt-1 mouse model of breast cancer.  

PubMed

Fibroblast growth factor (FGF) cooperates with the Wnt/beta-catenin pathway to promote mammary tumorigenesis. To investigate the mechanisms involved in FGF/Wnt cooperation, we genetically engineered a model of inducible FGF receptor (iFGFR) signaling in the context of the well-established mouse mammary tumor virus-Wnt-1 transgenic mouse. In the bigenic mice, iFGFR1 activation dramatically enhanced mammary tumorigenesis. Expression microarray analysis did not show transcriptional enhancement of Wnt/beta-catenin target genes but instead showed a translational gene signature that also correlated with elevated FGFR1 and FGFR2 in human breast cancer data sets. Additionally, iFGFR1 activation enhanced recruitment of RNA to polysomes, resulting in a marked increase in protein expression of several different Wnt/beta-catenin target genes. FGF pathway activation stimulated extracellular signal-regulated kinase and the phosphorylation of key translation regulators both in vivo in the mouse model and in vitro in a human breast cancer cell line. Our results suggest that cooperation of the FGF and Wnt pathways in mammary tumorigenesis is based on the activation of protein translational pathways that result in, but are not limited to, increased expression of Wnt/beta-catenin target genes (at the level of protein translation). Further, they reveal protein translation initiation factors as potential therapeutic targets for human breast cancers with alterations in FGF signaling. PMID:20501844

Pond, Adam C; Herschkowitz, Jason I; Schwertfeger, Kathryn L; Welm, Bryan; Zhang, Yiqun; York, Brian; Cardiff, Robert D; Hilsenbeck, Susan; Perou, Charles M; Creighton, Chad J; Lloyd, Richard E; Rosen, Jeffrey M

2010-06-15

293

Acetylation of the human T-cell leukemia virus type 1 Tax oncoprotein by p300 promotes activation of the NF-{kappa}B pathway  

SciTech Connect

The oncogenic potential of the HTLV-1 Tax protein involves activation of the NF-{kappa}B pathway, which depends on Tax phosphorylation, ubiquitination and sumoylation. We demonstrate that the nuclei of Tax-expressing cells, including HTLV-1 transformed T-lymphocytes, contain a pool of Tax molecules acetylated on lysine residue at amino acid position 346 by the transcriptional coactivator p300. Phosphorylation of Tax on serine residues 300/301 was a prerequisite for Tax localization in the nucleus and correlated with its subsequent acetylation by p300, whereas sumoylation, resulting in the formation of Tax nuclear bodies in which p300 was recruited, favored Tax acetylation. Overexpression of p300 markedly increased Tax acetylation and the ability of a wild type HTLV-1 provirus, -but not of a mutant provirus carrying an acetylation deficient Tax gene-, to activate gene expression from an integrated NF-{kappa}B-controlled promoter. Thus, Tax acetylation favors NF-{kappa}B activation and might play an important role in HTLV-1-induced cell transformation.

Lodewick, Julie; Lamsoul, Isabelle; Polania, Angela; Lebrun, Sylvie [Institute for Microbiological Research J-M Wiame and Laboratory of Microbiology, Universite Libre de Bruxelles, 1, Avenue Emile Gryson, B-1070 Brussels (Belgium); Burny, Arsene [Faculte des Sciences Agronomiques de Gembloux, Gembloux (Belgium); Ratner, Lee [Division of Molecular Oncology, Washington University School of Medicine, St Louis (United States); Bex, Francoise [Institute for Microbiological Research J-M Wiame and Laboratory of Microbiology, Universite Libre de Bruxelles, 1, Avenue Emile Gryson, B-1070 Brussels (Belgium)], E-mail: fbex@ulb.ac.be

2009-03-30

294

Bcl-3, induced by Tax and HTLV-1, inhibits NF-?B activation and promotes autophagy.  

PubMed

The human T cell leukemia virus type 1 (HTLV-1) is a complex human retrovirus that causes an aggressive leukemia known as adult T cell leukemia (ATL). The HTLV-1-encoded oncoprotein Tax induces persistent activation of the nuclear factor-?B (NF-?B) pathway, which is perceived as the primary cause of ATL. Bcl-3, a member of the NF-?B inhibitor (I?B) family, is highly expressed in many HTLV-1-infected T cell lines and ATL cells. However, the role of Bcl-3 in Tax-induced NF-?B activation has not been fully elucidated. Here, we show that Tax induces Bcl-3 expression, which in turn negatively regulates the Tax-induced NF-?B activation. Interestingly, both Bcl-3 up-regulation and NF-?B inhibition promote the autophagy process in HTLV-1-infected cells. Consistent with this, over-expression of Bcl-3 also results in enhancement of rapamycin-, pifithrin-?- or starvation-induced autophagy in control cells. Together, these data demonstrate that Bcl-3 acts as a negative regulator of NF-?B activation and promotes autophagy in HTLV-1-infected cells. PMID:24044922

Wang, Jinheng; Niu, Zhiguo; Shi, Ying; Gao, Cai; Wang, Xia; Han, Jingxian; Li, Junying; Gao, Zhitao; Zhu, Xiaofei; Song, Xiangfeng; Qin, Zhihai; Wang, Hui

2013-12-01

295

Comparison of peptide enzyme-linked immunosorbent assay and radioimmunoprecipitation assay with in vitro-translated proteins for detection of serum antibodies to human papillomavirus type 16 E6 and E7 proteins.  

PubMed

Antibodies to human papilloma virus (HPV) type 16 (HPV-16) E6 and E7 proteins in serum are markers for HPV-associated invasive cervical carcinoma. We compared two assays, a radioimmunoprecipitation assay with in vitro-translated HPV-16 E6 and E7 proteins and an enzyme-linked immunosorbent assay (ELISA) with E6 and E7 synthetic peptides, for their abilities to discriminate serologically between patients with invasive cervical cancer and controls. Among the patients, antibody prevalences were higher by the E6 radioimmunoprecipitation assay (55.7%) than by the E6 peptide ELISA (15.5%), but among the controls, they were lower by the radioimmunoprecipitation assay (1.7%) than by the E6 peptide ELISA (5%). For E7, antibody prevalences among the patients were comparable by the radioimmunoprecipitation assay (43%) and the peptide ELISA (41%), but among the controls they were higher by the E7 peptide ELISA (17.4%) than by the radioimmunoprecipitation assay (4.1%). There was good agreement between the E7 radioimmunoprecipitation assay and the E7 peptide ELISA among patients but not among controls. In tests with representative sera, heat denaturation of the translated proteins resulted in a complete loss of reactivity to the E6 protein and a marked decrease in reactivity to the E7 protein. Our study showed that the radioimmunoprecipitation assay discriminates better than the peptide ELISA between patients with invasive cervical cancer and controls and that this is related to the ability of the radioimmunoprecipitation assay to detect conformational epitopes. PMID:7529250

Sun, Y; Shah, K V; Müller, M; Muńoz, N; Bosch, X F; Viscidi, R P

1994-09-01

296

Ligand binding to heme proteins: III. FTIR studies of His-E7 and Val-E11 mutants of carbonmonoxymyoglobin.  

PubMed Central

Fouier-transform infrared (FTIR) difference spectra of several His-E7 and Val-E11 mutants of sperm whale carbonmonoxymyoglobin were obtained by photodissociation at cryogenic temperatures. The IR absorption of the CO ligand shows characteristic features for each of the mutants, both in the ligand-bound (A) state and in the photodissociated (B) state. For most of the mutants, a single A substate band is observed, which points to the crucial role of the His-E7 residue in determining the A substrate spectrum of the bound CO in the native structure. The fact that some of the mutants show more than one stretch band of the bound CO indicates that the appearance of multiple A substates is not exclusively connected to the presence of His-E7. In all but one mutant, multiple stretch bands of the CO in the photodissociated state are observed; these B substates are thought to arise from discrete positions and/or orientations of the photodissociated ligand in the heme pocket. The red shifts of the B bands with respect to the free-gas frequency indicate weak binding in the heme pocket. The observation of similar red shifts in microperoxidase (MP-8), where there is no residue on the distal side, suggests that the photodissociated ligand is still associated with the heme iron. Photoselection experiments were performed to determine the orientation of the bound ligand with respect to the heme normal by photolyzing small fractions of the sample with linearly polarized light at 540 nm. The resulting linear dichroism in the CO stretch spectrum yielded angles alpha > 20 degrees between the CO molecular axis and the heme normal for all of the mutants. We conclude that the off-axis position of the CO ligand in the native structure does not arise from steric constraints imposed by the distal histidine. There is no clear correlation between the size of the distal residue and the alpha of the CO ligand. PMID:8312483

Braunstein, D. P.; Chu, K.; Egeberg, K. D.; Frauenfelder, H.; Mourant, J. R.; Nienhaus, G. U.; Ormos, P.; Sligar, S. G.; Springer, B. A.; Young, R. D.

1993-01-01

297

Chimeric DNA vaccine reverses morphine-induced immunosuppression and tumorigenesis.  

PubMed

Although long-term use of morphine has been shown to promote tumor growth, the question whether tumorigenesis occurs as a result of an immunosuppressive effect remains to be investigated. In mice rendered tolerant to morphine, the efficacy and mechanism of a vaccination to rescue morphine-induced immunosuppression and prevent tumor growth was assessed both in vitro and in vivo. Herein, we found that morphine-injected mice exhibited higher tumor growth rates and lower percentages of CD8+ T lymphocytes. The mechanism of morphine suppression of immunity might be through the suppression of E7-specific CD8+ T lymphocyte proliferation and the promotion of apoptosis of these cells by the Bcl-2 and Bax pathways. The suppressive effect of E7-specific CD8+ T lymphocytes by morphine could be reversed by naloxone. We have previously shown that calreticulin linked with E7 (CRT/E7) could enhance the CD8+ T cell response and the anti-tumor effects (W. F. Cheng et al. (2001) J. Clin. Invest. 108, 669-678). CRT/E7 DNA vaccine could overcome the immunosuppressive effect of morphine and suppress tumor growth. Our findings reveal that long-term morphine treatment dose-dependently promotes tumor growth and a DNA vaccine may serve as a useful approach to treat the profound immunosuppressive function and prevent tumorigenesis after long-term morphine treatment. PMID:16140583

Cheng, Wen-Fang; Chen, Li-Kuei; Chen, Chi-An; Chang, Ming-Cheng; Hsiao, Po-Ni; Su, Yi-Ning; Lee, Chien-Nan; Jeng, Huei-Jiuan; Hsieh, Chang-Yao; Sun, Wei-Zen

2006-01-01

298

Proton electron nuclear double resonance from nitrosyl horse heart myoglobin: the role of His-E7 and Val-E11.  

PubMed Central

Electron nuclear double resonance (ENDOR) spectroscopy has been used to study protons in nitrosyl horse heart myoglobin (MbNO). (1)H ENDOR spectra were recorded for different settings of the magnetic field. Detailed analysis of the ENDOR powder spectra, using computer simulation, based on the "orientation-selection" principle, leads to the identification of the available protons in the heme pocket. We observe hyperfine interactions of the N(HisF8)-Fe(2+)-N(NO) complex with five protons in axial and with eight protons in the rhombic symmetry along different orientations, including those of the principal axes of the g-tensor. Protons from His-E7 and Val-E11 residues are identified in the two symmetries, rhombic and axial, exhibited by MbNO. Our results indicate that both residues are present inside the heme pocket and help to stabilize one particular conformation. PMID:10733988

Flores, M; Wajnberg, E; Bemski, G

2000-01-01

299

Reduction of Escherichia coli O157:H7 Populations in Cattle by Addition of Colicin E7-Producing E. coli to Feed  

PubMed Central

A cattle trial using artificially inoculated calves was conducted to determine the effect of the addition of colicinogenic Escherichia coli strains capable of producing colicin E7 (a 61-kDa DNase) to feed on the fecal shedding of serotype O157:H7. The experiment was divided into three periods. In period 1, which lasted 24 days, six calves were used as controls, and eight calves received 107 CFU of E. coli (a mixture of eight colicinogenic E. coli strains) per g of feed. Both groups were orally inoculated with nalidixic acid-resistant E. coli O157:H7 strains 7 days after the treatment started. In periods 2 and 3, the treatment and control groups were switched, and the colicinogenic E. coli dose was increased 10-fold. During period 3, which lasted as long as period 1, both groups were reinoculated with E. coli O157:H7. The numbers of E. coli O157:H7 were consistently greater in the control groups during the three periods, but comparisons within each time period determined a statistically significant (P < 0.05) difference only at day 21 of period 1. However, when the daily average counts were compared between the period 1 control group and the period 3 treatment group that included the same six animals, an overall reduction of 1.1 log10 CFU/g was observed, with a maximum decrease of 1.8 log10 CFU/g at day 21 (overall statistical significance, P = 0.001). Serotype O157:H7 was detected in 44% of the treatment group's intestinal tissue samples and in 64% of those from the control group (P < 0.04). These results indicated that the daily addition of 108 CFU of colicin E7-producing E. coli per gram of feed could reduce the fecal shedding of serotype O157:H7. PMID:15466550

Schamberger, Gerry P.; Phillips, Ronald L.; Jacobs, Jennifer L.; Diez-Gonzalez, Francisco

2004-01-01

300

Intercellular trafficking of the nuclear oncoprotein DEK  

E-print Network

DEK is a biochemically distinct, conserved nonhistone protein that is vital to global heterochromatin integrity. In addition, DEK can be secreted and function as a chemotactic, proinflammatory factor. Here we show that ...

Ploegh, Hidde

301

Targeting MUC1-C is synergistic with bortezomib in downregulating TIGAR and inducing ROS-mediated myeloma cell death.  

PubMed

The proteosome inhibitor bortezomib (BTZ) induces endoplasmic reticulum and oxidative stress in multiple myeloma (MM) cells. The mucin 1 C-terminal subunit (MUC1-C) oncoprotein is aberrantly expressed in most MM cells, and targeting MUC1-C with GO-203, a cell-penetrating peptide inhibitor of MUC1-C homodimerization, is effective in inducing reactive oxygen species (ROS)-mediated MM cell death. The present results demonstrate that GO-203 and BTZ synergistically downregulate expression of the p53-inducible regulator of glycolysis and apoptosis (TIGAR), which promotes shunting of glucose-6-phosphate into the pentose phosphate pathway to generate reduced glutathione (GSH). In turn, GO-203 blocks BTZ-induced increases in GSH and results in synergistic increases in ROS and MM cell death. The results also demonstrate that GO-203 is effective against BTZ-resistant MM cells. We show that BTZ resistance is associated with BTZ-induced increases in TIGAR and GSH levels, and that GO-203 resensitizes BTZ-resistant cells to BTZ treatment by synergistically downregulating TIGAR and GSH. The GO-203/BTZ combination is thus highly effective in killing BTZ-resistant MM cells. These findings support a model in which targeting MUC1-C is synergistic with BTZ in suppressing TIGAR-mediated regulation of ROS levels and provide an experimental rationale for combining GO-203 with BTZ in certain settings of BTZ resistance. PMID:24632713

Yin, Li; Kufe, Turner; Avigan, David; Kufe, Donald

2014-05-01

302

Inhibition of Topoisomerase IIa Expression by Transforming Growth Factor-b 1I s Abrogated by the Papillomavirus E7 Protein1  

Microsoft Academic Search

Transforming growth factor-b (TGF-b) protects normal cells from etoposide-induced cell death, yet the mechanism has remained speculative. Studies have shown that etoposide modifies the activity of the topoisomer- ase IIa (topo IIa) enzyme, thereby causing DNA damage and inducing cell death. Expression of topo IIa is necessary for etoposide-induced cell death, and peak expression of topo IIa normally occurs during

Daniel J. Satterwhite; Raymond L. White; Nori Matsunami; Kristi L. Neufeld

2000-01-01

303

Performance of HPV E6/E7 mRNA RT-qPCR for screening and diagnosis of cervical cancer with ThinPrep® Pap test samples.  

PubMed

Recent research has shown that oncogenic human papillomavirus (HPV) DNA, which is currently used in the screening and diagnosis of cervical cancer, can be detected not only in high-grade cervical lesions, but also in low-grade cervical lesions and normal tissues. For this reason, HPV tests targeting the E6 and E7 mRNA of five oncogenic HPV strains (HPV genotypes 16, 18, 31, 33, and 45), which are known to be responsible for the oncogenesis of cervical cancer, have been commercialized using a real-time nucleic acid sequence based amplification (NASBA) assay. Previous data has shown that the real-time NASBA assay has higher clinical specificity than HPV DNA testing (97.1% vs. 53.7%). However, the sensitivity of the real-time NASBA assay was lower than that of HPV DNA testing (41.1% vs. 100%). Despite the fact that there are more than 16 oncogenic HPV genotypes known to cause cervical cancer (HPV genotypes 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68, and 69), the commercialized real-time NASBA kit was designed to detect only five genotypes (16, 18, 31, 33, and 45). Therefore, in the present study, CervicGen HPV RT-qDX (Optipharm), a commercial diagnostic kit targeting a HPV E6/E7 mRNA based on RT-qPCR assay was evaluated with RNA extracted from ThinPrep® Pap samples, and the results were compared to real-time NASBA data. The sensitivity and specificity of the RT-qPCR assay were 91% and 98.6%, respectively, for the detection of cervical intraepithelial neoplasia CIN2(+) high-grade cervical lesions. Therefore, the CervicGen HPV RT-qDX assay showed a significantly higher sensitivity (91.1%) compared to the real-time NASBA assay (41.1%). In normal cytohistology cases, the specificity was 98.6% and 53.7% for HPV mRNA RT-qPCR and HPV DNA testing, respectively. These results demonstrate that HPV mRNA RT-qPCR better reflects clinical diagnosis. In conclusion, it is suggested that HPV mRNA RT-qPCR overcomes the shortcomings of lower specificity seen in the DNA assay and the lower sensitivity of the commercialized HPV mRNA real-time NASBA assay when testing from ThinPrep® Pap samples. PMID:25102300

Munkhdelger, Jijgee; Kim, Geehyuk; Wang, Hye-Young; Lee, Dongsup; Kim, Sunghyun; Choi, Yeonim; Choi, Eunhee; Park, Sunyoung; Jin, Hyunwoo; Park, Kwang Hwa; Lee, Hyeyoung

2014-10-01

304

HPV E6/E7 RNA In Situ Hybridization Signal Patterns as Biomarkers of Three-Tier Cervical Intraepithelial Neoplasia Grade  

PubMed Central

Cervical lesion grading is critical for effective patient management. A three-tier classification (cervical intraepithelial neoplasia [CIN] grade 1, 2 or 3) based on H&E slide review is widely used. However, for reasons of considerable inter-observer variation in CIN grade assignment and for want of a biomarker validating a three-fold stratification, CAP-ASCCP LAST consensus guidelines recommend a two-tier system: low- or high-grade squamous intraepithelial lesions (LSIL or HSIL). In this study, high-risk HPV E6/E7 and p16 mRNA expression patterns in eighty-six CIN lesions were investigated by RNAscope chromogenic in situ hybridization (CISH). Specimens were also screened by immunohistochemistry for p16INK4a (clone E6H4), and by tyramide-based CISH for HPV DNA. HPV genotyping was performed by GP5+/6+ PCR combined with cycle-sequencing. Abundant high-risk HPV RNA CISH signals were detected in 26/32 (81.3%) CIN 1, 22/22 (100%) CIN 2 and in 32/32 (100%) CIN 3 lesions. CIN 1 staining patterns were typified (67.7% specimens) by abundant diffusely staining nuclei in the upper epithelial layers; CIN 2 lesions mostly (66.7%) showed a combination of superficial diffuse-stained nuclei and multiple dot-like nuclear and cytoplasmic signals throughout the epithelium; CIN 3 lesions were characterized (87.5%) by multiple dot-like nuclear and cytoplasmic signals throughout the epithelial thickness and absence/scarcity of diffusely staining nuclei (trend across CIN grades: P<0.0001). These data are consistent with productive phase HPV infections exemplifying CIN 1, transformative phase infections CIN 3, whereas CIN 2 shows both productive and transformative phase elements. Three-tier data correlation was not found for the other assays examined. The dual discernment of diffuse and/or dot-like signals together with the assay’s high sensitivity for HPV support the use of HPV E6/E7 RNA CISH as an adjunct test for deciding lesion grade when CIN 2 grading may be beneficial (e.g. among young women) or when ‘LSIL vs. HSIL’ assignment is equivocal. PMID:24625757

Evans, Mark F.; Peng, Zhihua; Clark, Kelli M.; Adamson, Christine S.-C.; Ma, Xiao-Jun; Wu, Xingyong; Wang, Hongwei; Luo, Yuling; Cooper, Kumarasen

2014-01-01

305

Alteration of the lipid profile in lymphomas induced by MYC overexpression.  

PubMed

Overexpression of the v-myc avian myelocytomatosis viral oncogene homolog (MYC) oncogene is one of the most commonly implicated causes of human tumorigenesis. MYC is known to regulate many aspects of cellular biology including glucose and glutamine metabolism. Little is known about the relationship between MYC and the appearance and disappearance of specific lipid species. We use desorption electrospray ionization mass spectrometry imaging (DESI-MSI), statistical analysis, and conditional transgenic animal models and cell samples to investigate changes in lipid profiles in MYC-induced lymphoma. We have detected a lipid signature distinct from that observed in normal tissue and in rat sarcoma-induced lymphoma cells. We found 104 distinct molecular ions that have an altered abundance in MYC lymphoma compared with normal control tissue by statistical analysis with a false discovery rate of less than 5%. Of these, 86 molecular ions were specifically identified as complex phospholipids. To evaluate whether the lipid signature could also be observed in human tissue, we examined 15 human lymphoma samples with varying expression levels of MYC oncoprotein. Distinct lipid profiles in lymphomas with high and low MYC expression were observed, including many of the lipid species identified as significant for MYC-induced animal lymphoma tissue. Our results suggest a relationship between the appearance of specific lipid species and the overexpression of MYC in lymphomas. PMID:24994904

Eberlin, Livia S; Gabay, Meital; Fan, Alice C; Gouw, Arvin M; Tibshirani, Robert J; Felsher, Dean W; Zare, Richard N

2014-07-22

306

Metformin induces differentiation in acute promyelocytic leukemia by activating the MEK/ERK signaling pathway  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Metformin induces differentiation in NB4 and primary APL cells. Black-Right-Pointing-Pointer Metformin induces activation of the MEK/ERK signaling pathway in APL cells. Black-Right-Pointing-Pointer Metformin synergizes with ATRA to trigger maturation of NB4 and primary APL cells. Black-Right-Pointing-Pointer Metformin induces the relocalization and degradation of the PML-RAR{alpha} fusion protein. Black-Right-Pointing-Pointer The study may be applicable for new differentiation therapy in cancer treatment. -- Abstract: Recent studies have shown that metformin, a widely used antidiabetic agent, may reduce the risk of cancer development. In this study, we investigated the antitumoral effect of metformin on both acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL) cells. Metformin induced apoptosis with partial differentiation in an APL cell line, NB4, but only displayed a proapoptotic effect on several non-M3 AML cell lines. Further analysis revealed that a strong synergistic effect existed between metformin and all-trans retinoic acid (ATRA) during APL cell maturation and that metformin induced the hyperphosphorylation of extracellular signal-regulated kinase (ERK) in APL cells. U0126, a specific MEK/ERK activation inhibitor, abrogated metformin-induced differentiation. Finally, we found that metformin induced the degradation of the oncoproteins PML-RAR{alpha} and c-Myc and activated caspase-3. In conclusion, these results suggest that metformin treatment may contribute to the enhancement of ATRA-induced differentiation in APL, which may deepen the understanding of APL maturation and thus provide insight for new therapy strategies.

Huai, Lei; Wang, Cuicui; Zhang, Cuiping; Li, Qihui; Chen, Yirui; Jia, Yujiao; Li, Yan; Xing, Haiyan; Tian, Zheng; Rao, Qing; Wang, Min [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China)] [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China); Wang, Jianxiang, E-mail: wangjx@ihcams.ac.cn [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China)] [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China)

2012-06-08

307

Posttranscriptional repression of the cel gene of the ColE7 operon by the RNA-binding protein CsrA of Escherichia coli  

PubMed Central

Carbon storage regulator (CsrA) is a eubacterial RNA-binding protein that acts as a global regulator of many functionally diverse chromosomal genes. Here, we reveal that CsrA represses expression from an extrachromosomal element of Escherichia coli, the lysis gene (cel) of the ColE7 operon (cea-cei-cel). This operon and colicin expression are activated upon SOS response. Disruption of csrA caused ?5-fold increase of the lysis protein. Gel mobility shift assays established that both the single-stranded loop of the T1 stem–loop distal to cei, and the putative CsrA binding site overlapping the Shine–Dalgarno sequence (SD) of the cel gene are important for CsrA binding. Substitution mutations at SD relieved CsrA-dependent repression of the cel gene in vivo. Steady-state levels and half-life of the cel mRNA were not affected by CsrA, implying that regulation is mediated at the translational level. Levels of CsrB and CsrC sRNAs, which bind to and antagonize CsrA, were drastically reduced upon induction of the SOS response, while the CsrA protein itself remained unaffected. Thus, CsrA is a trans-acting modulator that downregulates the expression of lysis protein, which may confer a survival advantage on colicinogenic E. coli under environment stress conditions. PMID:20378712

Yang, Tsung-Yeh; Sung, Yun-Min; Lei, Guang-Sheng; Romeo, Tony; Chak, Kin-Fu

2010-01-01

308

Posttranscriptional repression of the cel gene of the ColE7 operon by the RNA-binding protein CsrA of Escherichia coli.  

PubMed

Carbon storage regulator (CsrA) is a eubacterial RNA-binding protein that acts as a global regulator of many functionally diverse chromosomal genes. Here, we reveal that CsrA represses expression from an extrachromosomal element of Escherichia coli, the lysis gene (cel) of the ColE7 operon (cea-cei-cel). This operon and colicin expression are activated upon SOS response. Disruption of csrA caused approximately 5-fold increase of the lysis protein. Gel mobility shift assays established that both the single-stranded loop of the T1 stem-loop distal to cei, and the putative CsrA binding site overlapping the Shine-Dalgarno sequence (SD) of the cel gene are important for CsrA binding. Substitution mutations at SD relieved CsrA-dependent repression of the cel gene in vivo. Steady-state levels and half-life of the cel mRNA were not affected by CsrA, implying that regulation is mediated at the translational level. Levels of CsrB and CsrC sRNAs, which bind to and antagonize CsrA, were drastically reduced upon induction of the SOS response, while the CsrA protein itself remained unaffected. Thus, CsrA is a trans-acting modulator that downregulates the expression of lysis protein, which may confer a survival advantage on colicinogenic E. coli under environment stress conditions. PMID:20378712

Yang, Tsung-Yeh; Sung, Yun-Min; Lei, Guang-Sheng; Romeo, Tony; Chak, Kin-Fu

2010-07-01

309

Molecular variants of human papilloma virus 16 E2, E4, E5, E6 and E7 genes associated with cervical neoplasia in Romanian patients.  

PubMed

The aim of this study was to identify and associate the sequence variations of human Papillomavirus 16 (HPV16) genes from women who live in two different areas of Romania and associate them with malignant progression. One hundred twenty-four HPV16-positive cervical isolates were collected, and the E2, E4, E5, E6 and E7 viral genes were sequenced. Two new missense mutations in the E6 gene (C279G and A305C) were found (together or alone, in association with other mutations) in 44 of 124 cases. The most frequently simultaneously mutated genes were E4/E2 hinge, E5 and E6 (p = 0.0004) in squamous cell carcinoma (SCC) samples. Also, for SCC patients, the best-correlated mutation patterns were obtained for E4/E2 hinge-E5 (r = 0.7984; p < 0.0001). No sample was found to have all of the investigated viral genes concurrently mutated. Phylogenetic analysis was performed to characterize the viral variants. Similar results were found for SCC and cervical intraepithelial neoplasia III (CINIII) cases. After all of the target gene sequences were assembled, all patients were found to be infected with viruses of the HPV16- European-German (EG) lineage, and two clusters were identified, the first (55/96 variants) from Moldavia and the second (41/96 variants) from Bucharest. The distinct cluster derived from EG in Moldavia could partially explain the increased frequency of SCC in this area. This study has generated a comprehensive set of sequence variation data on HPV16 circulating in Romania to join the existing data and highlight the important role of HPV16 variants during cervical carcinogenesis. PMID:25143263

Plesa, Adriana; Anton, Gabriela; Iancu, Iulia V; Diaconu, Carmen C; Huica, Irina; Stanescu, Anca D; Socolov, Demetra; Nistor, Elena; Popa, Elena; Stoian, Mihai; Botezatu, Anca

2014-12-01

310

Acetylshikonin induces apoptosis of hepatitis B virus X protein-expressing human hepatocellular carcinoma cells via endoplasmic reticulum stress.  

PubMed

Since it has been known that shikonin derived from a medicinal plant possesses anti-cancer activity, we wonder whether acetylshikonin (ASK), a derivate of shikonin, can be used to treat hepatocellular carcinoma cells expressing hepatitis B virus X protein (HBX), an oncoprotein from hepatitis B virus. When ASK was added to Hep3B cells stably expressing HBX, it induced apoptosis in a dose-dependent manner. ASK induced upregulation and export of Nur77 to the cytoplasm and activation of JNK. Likewise, suppression of Nur77 and JNK inactivation protected the cells from ASK-induced apoptosis, indicating that Nur77 upregulation and JNK activation were required for ASK-mediated apoptosis. Furthermore, ASK increased the expression of Bip and ubiquitination levels of cellular proteins, features of endoplasmic reticulum (ER) stress, via the production of reactive oxygen species in a dose-dependent manner. Suppression of reactive oxygen species with N-acetylcysteine reduced levels of Bip protein and ubiquitination levels of cellular proteins during ASK treatment, leading to protection of cells from apoptosis. Cycloheximide treatment reduced ASK-induced ER stress, suggesting that protein synthesis is involved in ASK-induced ER stress. Moreover, we showed using salubrinal, an ER stress inhibitor that reactive oxygen species production, JNK activation, and Nur77 upregulation and its translocation to cytoplasm are necessary for ER-induced stress. Interestingly, we found that JNK inactivation suppresses ASK-induced ER stress, whereas Nur77 siRNA treatment does not, indicating that JNK is required for ASK-induced ER stress. Accordingly, we report that ASK induces ER stress, which is prerequisite for apoptosis of HBX-expressing hepatocellular carcinoma cells. PMID:24769509

Moon, Jeong; Koh, Sang Seok; Malilas, Waraporn; Cho, Il-Rae; Kaewpiboon, Chutima; Kaowinn, Sirichat; Lee, Keesook; Jhun, Byung Hak; Choi, Young Whan; Chung, Young-Hwa

2014-07-15

311

Biosynthesis of the Cyanogenic Glucosides Linamarin and Lotaustralin in Cassava: Isolation, Biochemical Characterization, and Expression Pattern of CYP71E7, the Oxime-Metabolizing Cytochrome P450 Enzyme1[OA  

PubMed Central

Cassava (Manihot esculenta) is a eudicotyledonous plant that produces the valine- and isoleucine-derived cyanogenic glucosides linamarin and lotaustralin with the corresponding oximes and cyanohydrins as key intermediates. CYP79 enzymes catalyzing amino acid-to-oxime conversion in cyanogenic glucoside biosynthesis are known from several plants including cassava. The enzyme system converting oxime into cyanohydrin has previously only been identified in the monocotyledonous plant great millet (Sorghum bicolor). Using this great millet CYP71E1 sequence as a query in a Basic Local Alignment Search Tool-p search, a putative functional homolog that exhibited an approximately 50% amino acid sequence identity was found in cassava. The corresponding full-length cDNA clone was obtained from a plasmid library prepared from cassava shoot tips and was assigned CYP71E7. Heterologous expression of CYP71E7 in yeast afforded microsomes converting 2-methylpropanal oxime (valine-derived oxime) and 2-methylbutanal oxime (isoleucine-derived oxime) to the corresponding cyanohydrins, which dissociate into acetone and 2-butanone, respectively, and hydrogen cyanide. The volatile ketones were detected as 2.4-dinitrophenylhydrazone derivatives by liquid chromatography-mass spectrometry. A KS of approximately 0.9 ?m was determined for 2-methylbutanal oxime based on substrate-binding spectra. CYP71E7 exhibits low specificity for the side chain of the substrate and catalyzes the conversion of aliphatic and aromatic oximes with turnovers of approximately 21, 17, 8, and 1 min?1 for the oximes derived from valine, isoleucine, tyrosine, and phenylalanine, respectively. A second paralog of CYP71E7 was identified by database searches and showed approximately 90% amino acid sequence identity. In tube in situ polymerase chain reaction showed that in nearly unfolded leaves, the CYP71E7 paralogs are preferentially expressed in specific cells in the endodermis and in most cells in the first cortex cell layer. In fully unfolded leaves, the expression is pronounced in the cortex cell layer just beside the epidermis and in specific cells in the vascular tissue cortex cells. Thus, the transcripts of the CYP71E7 paralogs colocalize with CYP79D1 and CYP79D2. We conclude that CYP71E7 is the oxime-metabolizing enzyme in cyanogenic glucoside biosynthesis in cassava. PMID:21045121

J?rgensen, Kirsten; Morant, Anne Vinther; Morant, Marc; Jensen, Niels Bjerg; Olsen, Carl Erik; Kannangara, Rubini; Motawia, Mohammed Saddik; M?ller, Birger Lindberg; Bak, S?ren

2011-01-01

312

HIV-1 Nef and KSHV oncogene K1 synergistically promote angiogenesis by inducing cellular miR-718 to regulate the PTEN/AKT/mTOR signaling pathway  

PubMed Central

Kaposi's sarcoma (KS) is an AIDS-defining cancer with aberrant neovascularization caused by KS-associated herpesvirus (KSHV). Although the interaction between HIV-1 and KSHV plays a pivotal role in promoting the aggressive manifestations of KS, the pathogenesis underlying AIDS-KS remains largely unknown. Here we examined HIV-1 Nef protein promotion of KSHV oncoprotein K1-induced angiogenesis. We showed that both internalized and ectopic expression of Nef in endothelial cells synergized with K1 to facilitate vascular tube formation and cell proliferation, and enhance angiogenesis in a chicken CAM model. In vivo experiments further indicated that Nef accelerated K1-induced angiogenesis and tumorigenesis in athymic nu/nu mice. Mechanistic studies revealed that Nef and K1 synergistically activated PI3K/AKT/mTOR signaling by downregulating PTEN. Furthermore, Nef and K1 induced cellular miR-718, which inhibited PTEN expression by directly targeting a seed sequence in the 3? UTR of its mRNA. Inhibition of miR-718 expression increased PTEN synthesis and suppressed the synergistic effect of Nef- and K1-induced angiogenesis and tumorigenesis. These results indicate that, by targeting PTEN, miR-718 mediates Nef- and K1-induced angiogenesis via activation of AKT/mTOR signaling. Our results demonstrate an essential role of miR-718/AKT/mTOR axis in AIDS-KS and thus may represent an attractive therapeutic target. PMID:25104021

Xue, Min; Yao, Shuihong; Hu, Minmin; Li, Wan; Hao, Tingting; Zhou, Feng; Zhu, Xiaofei; Lu, Hongmei; Qin, Di; Yan, Qin; Zhu, Jianzhong; Gao, Shou-Jiang; Lu, Chun

2014-01-01

313

Epstein-Barr virus EBNA3C can disrupt multiple cell cycle checkpoints and induce nuclear division divorced from cytokinesis.  

PubMed

Expression of EBNA3C is essential for the immortalization of B cells by EBV in vitro and, in co-operation with activated ras, EBNA3C has oncogenic activity in primary rodent fibroblasts. This suggested that this viral oncoprotein might disrupt the cyclin/CDK-pRb-E2F pathway, which regulates cell cycle progression at the restriction point (R-point) in G1 of the proliferation cycle. An assay was established in which transfected EBNA3C-positive cells could be sorted and simultaneously analysed for their distribution in the cell cycle. This revealed that in NIH3T3 fibroblasts compelled to arrest by serum-withdrawal, EBNA3C induces nuclear division that is often divorced from cytokinesis and so produces bi- and multinucleated cells. This was confirmed using the ecdysone-inducible system for expression of EBNA3C in human U2OS cells and by microinjection of expression vectors into NIH3T3 and U2OS. Further analysis revealed that in the inducible system, EBNA3C expression inhibits the accumulation of p27(K1P1) but not the dephosphorylation of pRb. Experiments using the microtubule destabilizing drug nocodazole, showed that EBNA3C could abrogate the mitotic spindle checkpoint. PMID:10698515

Parker, G A; Touitou, R; Allday, M J

2000-02-01

314

Review article Induced seismicity and hydraulic fracturing for the recovery of  

E-print Network

that earthquakes can be induced by fluid injection. At that time, military waste fluid was injected into a 3671-m-deep and magnitudes are (a) mining (M 1.6e5.6); (b) oil and gas field depletion (M 1.0e7.3); (c) water injection.3); (f) academic research boreholes investigating induced seismicity and stress (M 2.8e3.1); (g) solution

Foulger, G. R.

315

Nonspecific T-cell homing during inflammation in atopic dermatitis: Expression of cutaneous lymphocyte-associated antigen and integrin ?E?7 on skin-infiltrating T cells  

Microsoft Academic Search

Atopic dermatitis (AD) is a chronic skin disorder, characterized by infiltration of activated memory CD4+ T cells into skin. A model to study the onset of allergic inflammation in a patient with AD is the atopy patch test (APT), in which, by epicutaneous application of aeroallergen, an eczematous reaction is induced in 50% of sensitized patients with AD. Extravasation of

I. Jolanda M. de Vries; Elisabeth G. Langeveld-Wildschut; Frank C. van Reijsen; Ilse C. Bihari; Carla A. F. M. Bruijnzeel-Koomen; Theo Thepen

1997-01-01

316

Human Papillomavirus Type 8 Interferes with a Novel C/EBP?-Mediated Mechanism of Keratinocyte CCL20 Chemokine Expression and Langerhans Cell Migration  

PubMed Central

Infection with genus beta human papillomaviruses (HPV) is implicated in the development of non-melanoma skin cancer. This was first evidenced for HPV5 and 8 in patients with epidermodysplasia verruciformis (EV), a genetic skin disease. So far, it has been unknown how these viruses overcome cutaneous immune control allowing their persistence in lesional epidermis of these patients. Here we demonstrate that Langerhans cells, essential for skin immunosurveillance, are strongly reduced in HPV8-positive lesional epidermis from EV patients. Interestingly, the same lesions were largely devoid of the important Langerhans cells chemoattractant protein CCL20. Applying bioinformatic tools, chromatin immunoprecipitation assays and functional studies we identified the differentiation-associated transcription factor CCAAT/enhancer binding protein ? (C/EBP?) as a critical regulator of CCL20 gene expression in normal human keratinocytes. The physiological relevance of this finding is supported by our in vivo studies showing that the expression patterns of CCL20 and nuclear C/EBP? converge spatially in the most differentiated layers of human epidermis. Our analyses further identified C/EBP? as a novel target of the HPV8 E7 oncoprotein, which co-localizes with C/EBP? in the nucleus, co-precipitates with it and interferes with its binding to the CCL20 promoter in vivo. As a consequence, the HPV8 E7 but not E6 oncoprotein suppressed C/EBP?-inducible and constitutive CCL20 gene expression as well as Langerhans cell migration. In conclusion, our study unraveled a novel molecular mechanism central to cutaneous host defense. Interference of the HPV8 E7 oncoprotein with this regulatory pathway allows the virus to disrupt the immune barrier, a major prerequisite for its epithelial persistence and procarcinogenic activity. PMID:22911498

Walch-Ruckheim, Barbara; Wickenhauser, Claudia; Doorbar, John; Pfister, Herbert; Malejczyk, Magdalena; Majewski, Slawomir; Keates, Andrew C.; Smola, Sigrun

2012-01-01

317

Human papillomavirus type 8 interferes with a novel C/EBP?-mediated mechanism of keratinocyte CCL20 chemokine expression and Langerhans cell migration.  

PubMed

Infection with genus beta human papillomaviruses (HPV) is implicated in the development of non-melanoma skin cancer. This was first evidenced for HPV5 and 8 in patients with epidermodysplasia verruciformis (EV), a genetic skin disease. So far, it has been unknown how these viruses overcome cutaneous immune control allowing their persistence in lesional epidermis of these patients. Here we demonstrate that Langerhans cells, essential for skin immunosurveillance, are strongly reduced in HPV8-positive lesional epidermis from EV patients. Interestingly, the same lesions were largely devoid of the important Langerhans cells chemoattractant protein CCL20. Applying bioinformatic tools, chromatin immunoprecipitation assays and functional studies we identified the differentiation-associated transcription factor CCAAT/enhancer binding protein ? (C/EBP?) as a critical regulator of CCL20 gene expression in normal human keratinocytes. The physiological relevance of this finding is supported by our in vivo studies showing that the expression patterns of CCL20 and nuclear C/EBP? converge spatially in the most differentiated layers of human epidermis. Our analyses further identified C/EBP? as a novel target of the HPV8 E7 oncoprotein, which co-localizes with C/EBP? in the nucleus, co-precipitates with it and interferes with its binding to the CCL20 promoter in vivo. As a consequence, the HPV8 E7 but not E6 oncoprotein suppressed C/EBP?-inducible and constitutive CCL20 gene expression as well as Langerhans cell migration. In conclusion, our study unraveled a novel molecular mechanism central to cutaneous host defense. Interference of the HPV8 E7 oncoprotein with this regulatory pathway allows the virus to disrupt the immune barrier, a major prerequisite for its epithelial persistence and procarcinogenic activity. PMID:22911498

Sperling, Tanya; O?dak, Monika; Walch-Rückheim, Barbara; Wickenhauser, Claudia; Doorbar, John; Pfister, Herbert; Malejczyk, Magdalena; Majewski, S?awomir; Keates, Andrew C; Smola, Sigrun

2012-01-01

318

2005LANDESBIOSCIENCE.DONOTDISTRIBUTE. [Autophagy 2:2, e1-e7, EPUB Ahead of Print: http://www.landesbioscience.com/journals/autophagy/abstract.php?id=2458; April/May/June 2006]; 2006 Landes Bioscience  

E-print Network

© 2005LANDESBIOSCIENCE.DONOTDISTRIBUTE. [Autophagy 2:2, e1-e7, EPUB Ahead of Print: http://www.landesbioscience.com/journals/autophagy/abstract.php?id=2458; April/May/June 2006]; ©2006 Landes Bioscience e1 Autophagy 2006; Vol. 2 Issue 2 Joëlle Botti for Autophagy, Volume 2, Issue 2. Definitive page numbers have not been assigned. The current citation is

Paris-Sud XI, Université de

319

Wip1 and p53 contribute to HTLV-1 Tax-induced tumorigenesis  

PubMed Central

Background Human T-cell Leukemia Virus type 1 (HTLV-1) infects 20 million individuals world-wide and causes Adult T-cell Leukemia/Lymphoma (ATLL), a highly aggressive T-cell cancer. ATLL is refractory to treatment with conventional chemotherapy and fewer than 10% of afflicted individuals survive more than 5 years after diagnosis. HTLV-1 encodes a viral oncoprotein, Tax, that functions in transforming virus-infected T-cells into leukemic cells. All ATLL cases are believed to have reduced p53 activity although only a minority of ATLLs have genetic mutations in their p53 gene. It has been suggested that p53 function is inactivated by the Tax protein. Results Using genetically altered mice, we report here that Tax expression does not achieve a functional equivalence of p53 inactivation as that seen with genetic mutation of p53 (i.e. a p53?/? genotype). Thus, we find statistically significant differences in tumorigenesis between Tax+p53+/+versus Tax+p53?/? mice. We also find a role contributed by the cellular Wip1 phosphatase protein in tumor formation in Tax transgenic mice. Notably, Tax+Wip1?/? mice show statistically significant reduced prevalence of tumorigenesis compared to Tax+Wip1+/+ counterparts. Conclusions Our findings provide new insights into contributions by p53 and Wip1 in the in vivo oncogenesis of Tax-induced tumors in mice. PMID:23256545

2012-01-01

320

Generation of induced pluripotent stem cells from primary chronic myelogenous leukemia patient samples.  

PubMed

Induced pluripotent stem cells (iPSCs) can be generated by the expression of defined transcription factors not only from normal tissue, but also from malignant cells. Cancer-derived iPSCs are expected to provide a novel experimental opportunity to establish the disease model. We generated iPSCs from imatinib-sensitive chronic myelogenous leukemia (CML) patient samples. Remarkably, the CML-iPSCs were resistant to imatinib although they consistently expressed BCR-ABL oncoprotein. In CML-iPSCs, the phosphorylation of ERK1/2, AKT, and JNK, which are essential for the maintenance of both BCR-ABL (+) leukemia cells and iPSCs, were unchanged after imatinib treatment, whereas the phosphorylation of signal transducer and activator of transcription (STAT)5 and CRKL was significantly decreased. These results suggest that the signaling for iPSCs maintenance compensates for the inhibition of BCR-ABL. CML-iPSC-derived hematopoietic cells recovered the sensitivity to imatinib although CD34(+)38(-)90(+)45(+) immature cells were resistant to imatinib, which recapitulated the pathophysiologic feature of the initial CML. CML-iPSCs provide us with a novel platform to investigate CML pathogenesis on the basis of patient-derived samples. PMID:22592606

Kumano, Keiki; Arai, Shunya; Hosoi, Masataka; Taoka, Kazuki; Takayama, Naoya; Otsu, Makoto; Nagae, Genta; Ueda, Koki; Nakazaki, Kumi; Kamikubo, Yasuhiko; Eto, Koji; Aburatani, Hiroyuki; Nakauchi, Hiromitsu; Kurokawa, Mineo

2012-06-28

321

Neoplastic Transformation of Human Small Airway Epithelial Cells Induced by Arsenic  

PubMed Central

Human small airway epithelial cells (SAECs) previously immortalized with human telomerase reverse transcriptase (h-TERT) were continuously treated with sodium arsenite at a dose of 0.5 ?g/mL in culture for up to 6 months. Arsenic-treated cells progressively displayed an increase in transformed phenotype including enhanced growth saturation density, plating efficiency, and anchorage-independent growth and invasion capability compared with their nontreated control cells. To determine whether arsenic-induced cell transformation was associated with genomic instability, treated and control cells were also analyzed for micronuclei formation. A 4.8-fold increase in micronuclei incidence in arsenic-treated cells was detected in conjunction with increased N-phosphonacetyl-l-aspartate (PALA)-resistant characteristics. In addition, arsenic-treated cells showed an increase in c-H-ras, c-myc, and c-fos protein expression relative to controls. The change in oncoprotein expression correlated with a decrease in wild-type p53 expression and hyperphosphorylated retinoblastoma. Taken together, these results strongly suggest that h-TERT immortalized human small airway epithelial cells underwent step-wise transformation after inorganic arsenic treatment. PMID:18037969

Wen, Gengyun; Calaf, Gloria M; Partridge, Michael A; Echiburu-Chau, Carlos; Zhao, Yongliang; Huang, Sarah; Chai, Yunfei; Li, Bingyan; Hu, Burong; Hei, Tom K

2008-01-01

322

Phosphorylated ezrin is associated with EBV latent membrane protein 1 in nasopharyngeal carcinoma and induces cell migration  

PubMed Central

Tumor metastasis is a complex phenomenon that is the culmination of effects of numerous cellular factors. We have shown that the EBV oncoprotein, latent membrane protein 1 (LMP1), is capable of inducing a wide range of such factors in cell culture, expression of which is also elevated in the LMP1-expressing tumor, nasopharyngeal carcinoma (NPC), a highly invasive neoplasm. Recently, the membrane-crosslinker protein ezrin has been implicated in tumor cell metastasis and malignant progression. In this study, we evaluated the possible role of LMP1 and ezrin in the pathophysiology of NPC. We show that C-terminal phosphorylation of ezrin is increased by expression of LMP1 in nasopharyngeal (NP) cells through a Protein Kinase C (PKC) pathway. LMP1 enhances organization of a ternary complex of CD44, ezrin and F-actin which is a prerequisite for ezrin phosphorylation. In NPC tissues, expression of phosphoezrin and LMP1 is directly correlated. Silencing of endogenously expressed ezrin suppresses LMP1-induced cell motility and invasiveness. Moreover inhibition of ezrin phosphorylation by PKC inhibitor suppresses migration and invasion of NP cells. These data demonstrate that phosphorylation of ezrin and its recruitment to the cell membrane linked to F-actin and CD44 is a process required for LMP1-stimulated cell motility and invasion of NP cells. PMID:19234486

Endo, Kazuhira; Kondo, Satoru; Shackleford, Julia; Horikawa, Toshiyuki; Kitagawa, Noriko; Yoshizaki, Tomokazu; Furukawa, Mitsuru; Zen, Yoh; Pagano, Joseph S.

2009-01-01

323

Similarities between the Epstein-Barr Virus (EBV) Nuclear Protein EBNA1 and the Pioneer Transcription Factor FoxA: Is EBNA1 a “Bookmarking” Oncoprotein that Alters the Host Cell Epigenotype?  

PubMed Central

EBNA1, a nuclear protein expressed in all EBV-associated neoplasms is indispensable for the maintenance of the viral episomes in latently infected cells. EBNA1 may induce genetic alterations by upregulating cellular recombinases, production of reactive oxygen species (ROS) and affecting p53 levels and function. All these changes may contribute to tumorigenesis. In this overview we focus, however, on the epigenetic alterations elicited by EBNA1 by drawing a parallel between EBNA1 and the FoxA family of pioneer transcription factors. Both EBNA1 and FoxA induce local DNA demethylation, nucleosome destabilization and bind to mitotic chromosomes. Local DNA demethylation and nucleosome rearrangement mark active promoters and enhancers. In addition, EBNA1 and FoxA, when associated with mitotic chromatin may “bookmark” active genes and ensure their reactivation in postmitotic cells (epigenetic memory). We speculate that DNA looping induced by EBNA1-EBNA1 interactions may reorganize the cellular genome. Such chromatin loops, sustained in mitotic chromatin similarly to the long-distance interactions mediated by the insulator protein CTCF, may also mediate the epigenetic inheritance of gene expression patterns. We suggest that EBNA1 has the potential to induce patho-epigenetic alterations contributing to tumorigenesis.

Niller, Hans Helmut; Minarovits, Janos

2012-01-01

324

PDZ domain-binding motif of human T-cell leukemia virus type 1 Tax oncoprotein is essential for the interleukin 2 independent growth induction of a T-cell line  

Microsoft Academic Search

BACKGROUND: Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia (ATL), whereas HTLV type 2 (HTLV-2), is not associated with ATL or any other leukemia. HTLV-1 encodes the transforming gene tax1, whose expression in an interleukin (IL)-2-dependent T-cell line (CTLL-2) induces IL-2-independent growth. RESULTS: In this study, we demonstrated that IL-2-independent growth induction by

Chikako Tsubata; Masaya Higuchi; Masahiko Takahashi; Masayasu Oie; Yuetsu Tanaka; Fumitake Gejyo; Masahiro Fujii

2005-01-01

325

Tobacco exposure results in increased E6 and E7 oncogene expression, DNA damage and mutation rates in cells maintaining episomal human papillomavirus 16 genomes.  

PubMed

High-risk human papillomavirus (HR-HPV) infections are necessary but insufficient agents of cervical and other epithelial cancers. Epidemiological studies support a causal, but ill-defined, relationship between tobacco smoking and cervical malignancies. In this study, we used mainstream tobacco smoke condensate (MSTS-C) treatments of cervical cell lines that maintain either episomal or integrated HPV16 or HPV31 genomes to model tobacco smoke exposure to the cervical epithelium of the smoker. MSTS-C exposure caused a dose-dependent increase in viral genome replication and correspondingly higher early gene transcription in cells with episomal HPV genomes. However, MSTS-C exposure in cells with integrated HR-HPV genomes had no effect on genome copy number or early gene transcription. In cells with episomal HPV genomes, the MSTS-C-induced increases in E6 oncogene transcription led to decreased p53 protein levels and activity. As expected from loss of p53 activity in tobacco-exposed cells, DNA strand breaks were significantly higher but apoptosis was minimal compared with cells containing integrated viral genomes. Furthermore, DNA mutation frequencies were higher in surviving cells with HPV episomes. These findings provide increased understanding of tobacco smoke exposure risk in HPV infection and indicate tobacco smoking acts more directly to alter HR-HPV oncogene expression in cells that maintain episomal viral genomes. This suggests a more prominent role for tobacco smoke in earlier stages of HPV-related cancer progression. PMID:25064354

Wei, Lanlan; Griego, Anastacia M; Chu, Ming; Ozbun, Michelle A

2014-10-01

326

Roscovitine up-regulates p53 protein and induces apoptosis in human HeLaS(3) cervix carcinoma cells.  

PubMed

Exposure of human HeLaS(3) cervix carcinoma cells to high doses of conventional cytostatic drugs, e.g. cisplatin (CP) strongly inhibits their proliferation. However, most cytostatic agents are genotoxic and may generate a secondary malignancy. Therefore, therapeutic strategy using alternative, not cytotoxic drugs would be beneficial. Inhibition of cyclin-dependent kinases (CDKs) by pharmacological inhibitors became recently a promising therapeutic option. Roscovitine (ROSC), a selective CDK inhibitor, efficiently targets human malignant cells. ROSC induces cell cycle arrest and apoptosis in human MCF-7 breast cancer cells. ROSC also activates p53 protein. Activation of p53 tumor suppressor protein is essential for induction of apoptosis in MCF-7 cells. Considering the fact that in HeLaS(3) cells wt p53 is inactivated by the action of HPV-encoded E6 oncoprotein, we addressed the question whether ROSC would be able to reactivate p53 protein in them. Their exposure to ROSC for 24 h induced cell cycle arrest at G(2)/M and reduced the number of viable cells. Unlike CP, ROSC in the used doses did not induce DNA damage and was not directly cytotoxic. Despite lack of detectable DNA lesions, ROSC activated wt p53 protein. The increase of p53 levels was attributable to the ROSC-mediated protein stabilization. Further analyses revealed that ROSC induced site-specific phosphorylation of p53 protein at Ser46. After longer exposure, ROSC induced apoptosis in HeLaS(3) cells. These results indicate that therapy of HeLaS(3) cells by ROSC could offer an advantage over that by CP due to its increased selectivity and markedly reduced risk of generation of a secondary cancer. PMID:18846503

Wesierska-Gadek, Józefa; Wandl, Stefanie; Kramer, Matthias P; Pickem, Christian; Krystof, Vladimir; Hajek, Susanne B

2008-12-01

327

A mechanistic study on the metastasis inducing function of FUS-CHOP fusion protein in liposarcoma.  

PubMed

The FUS-CHOP fusion protein has been found to be instrumental for specific oncogenic processes in liposarcoma, but its ability to induce metastasis and the underlying mechanisms by which this can be achieved remain unknown. To dissect its functional role in this context, we stably overexpressed this protein in SW872 liposarcoma and HT1080 fibrosarcoma cell lines, and were able to demonstrate that forced expression of FUS-CHOP significantly increases migration and invasion, as well as enhances lung and liver metastasis in the in vivo chicken chorioallantoic membrane (CAM) model, that is proliferation independent. Additionally, FUS-CHOP enhances the expression of matrix-metalloproteinases -2 and -9, and transactivates their promoters in vitro. Mutational analysis showed that C/EBP-?- (-769/-755), NF-?B (-525/-516) and CREB/AP-1 (-218/-207) sites were important for MMP-2 and NF-?B (-604/-598), AP-1 (-539/-532) and AP-1 (-81/-72) for MMP-9 transactivation. Moreover, a direct in vivo interaction of FUS-CHOP was observed in case of the MMP-2 promoter within region (-769/-207). siRNA data revealed that MMP-2 expression is essential in the FUS-CHOP induced metastatic phenotype. MMP-2-mRNA and protein expression correlated significantly with FUS-CHOP positivity in 46 resected patient liposarcoma tissues. We have for the first time provided substantial evidence for the FUS-CHOP oncoprotein as an inducer of metastasis that is due to the transcriptional induction of specific tumor-associated proteases. Insights gained from this study not only support a deeper understanding of the mechanistic properties of FUS-CHOP, but also open up new avenues for targeted therapy. PMID:24285420

Patil, Nitin; Ahmed Kabeer Rasheed, Suhail; Abba, Mohammed; Hendrik Leupold, Jörg; Schwarzbach, Matthias; Allgayer, Heike

2014-06-15

328

Inhibition of Myc-induced cell transformation by brain acid-soluble protein 1 (BASP1)  

PubMed Central

Cell transformation by the Myc oncoprotein involves transcriptional activation or suppression of specific target genes with intrinsic oncogenic or tumor-suppressive potential, respectively. We have identified the BASP1 (CAP-23, NAP-22) gene as a novel target suppressed by Myc. The acidic 25-kDa BASP1 protein was originally isolated as a cortical cytoskeleton-associated protein from rat and chicken brain, but has also been found in other tissues and subcellular locations. BASP1 mRNA and protein expression is specifically suppressed in fibroblasts transformed by the v-myc oncogene, but not in cells transformed by other oncogenic agents. The BASP1 gene encompasses 2 exons separated by a 58-kbp intron and a Myc-responsive regulatory region at the 5? boundary of untranslated exon 1. Bicistronic expression of BASP1 and v-myc from a retroviral vector blocks v-myc-induced cell transformation. Furthermore, ectopic expression of BASP1 renders fibroblasts resistant to subsequent cell transformation by v-myc, and exogenous delivery of the BASP1 gene into v-myc-transformed cells leads to significant attenuation of the transformed phenotype. The inhibition of v-myc-induced cell transformation by BASP1 also prevents the transcriptional activation or repression of known Myc target genes. Mutational analysis showed that the basic N-terminal domain containing a myristoylation site, a calmodulin binding domain, and a putative nuclear localization signal is essential for the inhibitory function of BASP1. Our results suggest that down-regulation of the BASP1 gene is a necessary event in myc-induced oncogenesis and define the BASP1 protein as a potential tumor suppressor. PMID:19297618

Hartl, Markus; Nist, Andrea; Khan, M. Imran; Valovka, Taras; Bister, Klaus

2009-01-01

329

Development, characterization and distribution of adoptively transferred peripheral blood lymphocytes primed by human papillomavirus 18 E7--pulsed autologous dendritic cells in a patient with metastatic adenocarcinoma of the uterine cervix.  

PubMed

We describe a 27-year-old woman with systemic chemoresistant and radioresistant metastatic disease secondary to a recurrence of human papillomavirus (HPV) 18 infected cervical adenocarcinoma of the uterine cervix who received adoptive transfer of peripheral blood T cells stimulated with HPV 18 E7-pulsed autologous dendritic cells (DC). Extensive in vitro characterization of the DC-activated T cells derived from peripheral blood mononuclear cells (PBMC) included phenotypic analysis, cytotoxicity and intracellular cytokine production. High cytotoxicity activity was observed by CD8+T cells against autologous tumor cells, but not against NK-sensitive K562 cells, autologous Con-A lymphoblasts, or autologous Epstein-Barr virus-transformed lymphoblastoid cells. Blocking studies demonstrated that lytic activity was significantly inhibited by pretreatment of tumor targets with MAb specific for HLA class I as well as that of effector cells with anti-CD8, anti-LFA-1, but not anti CD3 MAb. Two-color flow cytometric analysis of the cytotoxic T cells revealed that a significant proportion of CD8+ cells was also CD56+. These double positive CTLs were thymically derived, as shown by expression of heterodimeric CD8 molecules (alpha/beta CD8) and were endowed with high cytotoxic activity against tumor cells. Analysis of intracellular cytokine expression showed that the striking majority of E7-pulsed DC activated CD8+ T cells strongly expressed IFN-gamma, TNF-alpha and IL-2 but not IL-4. The patient received two infusions of cytotoxic tumor-specific T cells at 2 week intervals, and in vivo distribution of the T cells was followed by 111 oxine labeling and serial gamma camera imaging. Persistent accumulation of radioactivity in the lungs, which harbored extensive metastatic disease, was detected up to 120 hrs after the infusion. Taken together, these results illustrate the potential of E7-specific and tumor-specific CTL-based immunotherapy for the treatment of patients with invasive cervical cancer. PMID:10726612

Santin, A D; Hermonat, P L; Ravaggi, A; Bellone, S; Cowan, C; Korourian, S; Pecorelli, S; Cannon, M J; Parham, G P

2000-01-01

330

Human and primate tumour viruses use PDZ binding as an evolutionarily conserved mechanism of targeting cell polarity regulators.  

PubMed

A unique feature of the cancer-causing mucosotropic human papillomaviruses (HPVs) is the ability of their E6 proteins to interact with a number of PDZ domain-containing cellular substrates, including the cell polarity regulators hDlg and hScrib. These interactions are essential for the ability of these viruses to induce malignant progression. Rhesus papillomaviruses (RhPV) are similar to their human counterparts in that they also cause anogenital malignancy in their host, the Rhesus Macaque. However, unlike HPV E6, the RhPV E6 has no PDZ-binding motif. We now show that such a motif is present on the RhPV E7 oncoprotein. This motif specifically confers PDZ-binding activity and directs the interaction of RhPV E7 with the cell polarity regulator Par3, which it targets for proteasome-mediated degradation. These results demonstrate an amazing evolutionary conservation of function between the RhPV and the HPV oncoproteins, where both target proteins of the same cell polarity control network, although through different components and pathways. PMID:18820705

Tomai?, V; Gardiol, D; Massimi, P; Ozbun, M; Myers, M; Banks, L

2009-01-01

331

Effects of the CDK-inhibitor CYC202 on p38 MAPK, ERK1/2 and c-Myc activities in papillomavirus type 16 E6- and E7-transformed human keratinocytes.  

PubMed

In the present study, we have investigated the effect of the chemical CDK-inhibitor CYC202 on E6 and E7-transformed keratinocytes, in which the function of the cellular cell cycle inhibitor p21Cip1 is abrogated by the viral genes. The cyto-toxicity and the inhibition of the cell growth were analysed by MTT assay and analysis of DNA synthesis respectively. The effect on some signalling molecules was tested by Western blot analysis. CYC202 effectively inhibited the proliferation of E6 and E7 keratinocytes in a dose-dependent manner. Treatment with CYC202 strongly increased the activity of p38 MAP kinase. Furthermore, it inhibited ERK1/2 at the highest concentration used and had no effect on the activity of JNK1/2. CYC202 also increased the phosphorylation of HSP27 and decreased the phosphorylation and DNA-binding activity of the transcriptional regulator c-Myc, in correlation with the corresponding upstream kinases p38 MAPK and ERK1/2. Our results provide additional data for the anti-proliferative actions and potency of the chemical CDK-inhibitor CYC202. PMID:17786366

Atanasova, Ganka N; Isaeva, Antonia R; Zhelev, Nikolai; Poumay, Yves; Mitev, Vanyo I

2007-10-01

332

The PDZ domain binding motif (PBM) of human T-cell leukemia virus type 1 Tax can be substituted by heterologous PBMs from viral oncoproteins during T-cell transformation.  

PubMed

Several tumor viruses, such as human T-cell leukemia virus (HTLV), human papilloma virus (HPV), human adenovirus, have high-oncogenic and low-oncogenic subtypes, and such subtype-specific oncogenesis is associated with the PDZ-domain binding motif (PBM) in their transforming proteins. HTLV-1, the causative agent of adult T-cell leukemia, encodes Tax1 with PBM as a transforming protein. The Tax1 PBM was substituted with those from other oncoviruses, and the transforming activity was examined. Tax1 mutants with PBM from either HPV-16 E6 or adenovirus type 9 E4ORF1 are fully active in the transformation of a mouse T-cell line from interleukin-2-dependent growth into independent growth. Interestingly, one such Tax1 PBM mutant had an extra amino acid insertion derived from E6 between PBM and the rest of Tax1, thus suggesting that the amino acid sequences of the peptides between PBM and the rest of Tax1 and the numbers only slightly affect the function of PBM in the transformation. Tax1 and Tax1 PBM mutants interacted with tumor suppressors Dlg1 and Scribble with PDZ-domains. Unlike E6, Tax1 PBM mutants as well as Tax1 did not or minimally induced the degradations of Dlg1 and Scribble, but instead induced their subcellular translocation from the detergent-soluble fraction into the insoluble fraction, thus suggesting that the inactivation mechanism of these tumor suppressor proteins is distinct. The present results suggest that PBMs of high-risk oncoviruses have a common function(s) required for these three tumor viruses to transform cells, which is likely associated with the subtype-specific oncogenesis of these tumor viruses. PMID:20069350

Aoyagi, Tomoya; Takahashi, Masahiko; Higuchi, Masaya; Oie, Masayasu; Tanaka, Yuetsu; Kiyono, Tohru; Aoyagi, Yutaka; Fujii, Masahiro

2010-04-01

333

The polycomb group protein Bmi-1 represses the tumor suppressor PTEN and induces epithelial-mesenchymal transition in human nasopharyngeal epithelial cells  

PubMed Central

The polycomb group protein B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1) is dysregulated in various cancers, and its upregulation strongly correlates with an invasive phenotype and poor prognosis in patients with nasopharyngeal carcinomas. However, the underlying mechanism of Bmi-1–mediated invasiveness remains unknown. In the current study, we found that upregulation of Bmi-1 induced epithelial-mesenchymal transition (EMT) and enhanced the motility and invasiveness of human nasopharyngeal epithelial cells, whereas silencing endogenous Bmi-1 expression reversed EMT and reduced motility. Furthermore, upregulation of Bmi-1 led to the stabilization of Snail, a transcriptional repressor associated with EMT, via modulation of PI3K/Akt/GSK-3? signaling. Chromatin immunoprecipitation assays revealed that Bmi-1 transcriptionally downregulated expression of the tumor suppressor PTEN in tumor cells through direct association with the PTEN locus. This in vitro analysis was consistent with the statistical inverse correlation detected between Bmi-1 and PTEN expression in a cohort of human nasopharyngeal carcinoma biopsies. Moreover, ablation of PTEN expression partially rescued the migratory/invasive phenotype of Bmi-1–silenced cells, indicating that PTEN might be a major mediator of Bmi-1–induced EMT. Our results provide functional and mechanistic links between the oncoprotein Bmi-1 and the tumor suppressor PTEN in the development and progression of cancer. PMID:19884659

Song, Li-Bing; Li, Jun; Liao, Wen-Ting; Feng, Yan; Yu, Chun-Ping; Hu, Li-Juan; Kong, Qing-Li; Xu, Li-Hua; Zhang, Xing; Liu, Wan-Li; Li, Man-Zhi; Zhang, Ling; Kang, Tie-Bang; Fu, Li-Wu; Huang, Wen-Lin; Xia, Yun-Fei; Tsao, Sai Wah; Li, Mengfeng; Band, Vimla; Band, Hamid; Shi, Qing-Hua; Zeng, Yi-Xin; Zeng, Mu-Sheng

2009-01-01

334

Human papillomavirus 16 E5 induces bi-nucleated cell formation by cell-cell fusion  

SciTech Connect

Human papillomaviruses (HPV) 16 is a DNA virus encoding three oncogenes - E5, E6, and E7. The E6 and E7 proteins have well-established roles as inhibitors of tumor suppression, but the contribution of E5 to malignant transformation is controversial. Using spontaneously immortalized human keratinocytes (HaCaT cells), we demonstrate that expression of HPV16 E5 is necessary and sufficient for the formation of bi-nucleated cells, a common characteristic of precancerous cervical lesions. Expression of E5 from non-carcinogenic HPV6b does not produce bi-nucleate cells. Video microscopy and biochemical analyses reveal that bi-nucleates arise through cell-cell fusion. Although most E5-induced bi-nucleates fail to propagate, co-expression of HPV16 E6/E7 enhances the proliferation of these cells. Expression of HPV16 E6/E7 also increases bi-nucleated cell colony formation. These findings identify a new role for HPV16 E5 and support a model in which complementary roles of the HPV16 oncogenes lead to the induction of carcinogenesis.

Hu Lulin; Plafker, Kendra [Department of Cell Biology, University of Oklahoma (United States); Vorozhko, Valeriya [Department of Cell Biology, University of Oklahoma (United States); Cell Cycle and Cancer Biology Research Program, Oklahoma Medical Research Foundation (United States); Zuna, Rosemary E. [Department of Pathology, University of Oklahoma HSC (United States); Hanigan, Marie H. [Department of Cell Biology, University of Oklahoma (United States); Gorbsky, Gary J. [Department of Cell Biology, University of Oklahoma (United States); Cell Cycle and Cancer Biology Research Program, Oklahoma Medical Research Foundation (United States); Plafker, Scott M. [Department of Cell Biology, University of Oklahoma (United States); Angeletti, Peter C. [Nebraska Center for Virology (United States); Ceresa, Brian P. [Department of Cell Biology, University of Oklahoma (United States)], E-mail: brian-ceresa@oushc.edu

2009-02-05

335

HMGA2 induces epithelial-to-mesenchymal transition in human hepatocellular carcinoma cells  

PubMed Central

Epithelial-to-mesenchymal transition (EMT) is an important event during tumorigenesis. The human high-mobility group A2 (HMGA2) is a chromatin-binding protein, which contains three AT-hook domains that enable its binding to the minor groove of DNA. HMGA2 organizes protein complexes on enhancers of various genes to regulate gene expression and cell differentiation. The HMGA2 protein has been reported to be overexpressed in many types of cancer. It is not known, however, whether HMGA2 regulates EMT in human hepatocellular carcinoma (HCC) cell lines, and the mechanism(s) have not been fully elucidated. In this study, the expression of HMGA2 in five HCC cell lines was examined. The levels of HMGA2 expression among the five HCC cell lines coincided with their invasiveness. The variation in HMGA2 expression significantly correlated with the expression of several putative EMT markers. In addition, assessment of the invasive potential, following transfection with HMGA2-siRNA, demonstrated that the rate of cell migration was significantly reduced, suggesting that HMGA2 may be an important contributor to the invasion of tumor cells and that expression levels of HMGA2 influence the metastatic behavior of HCC cells. To further confirm the conclusion and explore the molecular mechanism through which HMGA2 induces EMT, we found that HMGA2 upregulates the expression of Twist and Snail in HCC cell lines. In conclusion, this present study is the first to show that HMGA2 effectively regulates EMT to induce invasion and metastasis in HCC cells. The function of HMGA2 as an oncoprotein may be associated with several important molecules involved in invasion and metastasis of cancer cells. PMID:23599793

LUO, YIZHOU; LI, WENFENG; LIAO, HUI

2013-01-01

336

Human T-cell leukemia virus type I-mediated repression of PDZ-LIM domain-containing protein 2 involves DNA methylation but independent of the viral oncoprotein tax.  

PubMed

Human T-cell leukemia virus type I (HTLV-I) is the etiological agent of adult T-cell leukemia (ATL). Our recent studies have shown that one important mechanism of HTLV-I-Mediated tumorigenesis is through PDZ-LIM domain-containing protein 2 (PDLIM2) repression, although the involved mechanism remains unknown. Here, we further report that HTLV-I-Mediated PDLIM2 repression was a pathophysiological event and the PDLIM2 repression involved DNA methylation. Whereas DNA methyltransferases 1 and 3b but not 3a were upregulated in HTLV-I-transformed T cells, the hypomethylating agent 5-aza-2'-deoxycytidine (5-aza-dC) restored PDLIM2 expression and induced death of these malignant cells. Notably, the PDLIM2 repression was independent of the viral regulatory protein Tax because neither short-term induction nor long-term stable expression of Tax could downregulate PDLIM2 expression. These studies provide important insights into PDLIM2 regulation, HTLV-I leukemogenicity, long latency, and cancer health disparities. Given the efficient antitumor activity with no obvious toxicity of 5-aza-dC, these studies also suggest potential therapeutic strategies for ATL. PMID:19794962

Yan, Pengrong; Qu, Zhaoxia; Ishikawa, Chie; Mori, Naoki; Xiao, Gutian

2009-10-01

337

Human papillomavirus causes an angiogenic switch in keratinocytes which is sufficient to alter endothelial cell behavior  

SciTech Connect

One of the requirements for tumor growth is the ability to recruit a blood supply, a process known as angiogenesis. Angiogenesis begins early in the progression of cervical disease from mild to severe dysplasia and on to invasive cancer. We have previously reported that expression of human papillomavirus type 16 E6 and E7 (HPV16 E6E7) proteins in primary foreskin keratinocytes (HFKs) decreases expression of two inhibitors and increases expression of two angiogenic inducers [Toussaint-Smith, E., Donner, D.B., Roman, A., 2004. Expression of human papillomavirus type 16 E6 and E7 oncoproteins in primary foreskin keratinocytes is sufficient to alter the expression of angiogenic factors. Oncogene 23, 2988-2995]. Here we report that HPV-induced early changes in the keratinocyte phenotype are sufficient to alter endothelial cell behavior both in vitro and in vivo. Conditioned media from HPV16 E6E7 expressing HFKs as well as from human cervical keratinocytes containing the intact HPV16 were able to stimulate proliferation and migration of human microvascular endothelial cells. In addition, introduction of the conditioned media into immunocompetent mice using a Matrigel plug model resulted in a clear angiogenic response. These novel data support the hypothesis that HPV proteins contribute not only to the uncontrolled keratinocyte growth seen following HPV infection but also to the angiogenic response needed for tumor formation.

Chen, W. [Department of Microbiology and Immunology and the Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, 635 Barnhill Drive, Indianapolis, IN 46202-5120 (United States); Li, F.; Mead, L.; White, H. [Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Walker, J. [Department of Microbiology and Immunology and the Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, 635 Barnhill Drive, Indianapolis, IN 46202-5120 (United States); Ingram, D.A. [Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Roman, A. [Department of Microbiology and Immunology and the Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, 635 Barnhill Drive, Indianapolis, IN 46202-5120 (United States)], E-mail: aroman@iupui.edu

2007-10-10

338

Human cells compromised for p53 function exhibit defective global and transcription-coupled nucleotide excision repair, whereas cells compromised for pRb function are defective only in global repair.  

PubMed

After exposure to DNA-damaging agents, the p53 tumor suppressor protects against neoplastic transformation by inducing growth arrest and apoptosis. A series of investigations has also demonstrated that, in UV-exposed cells, p53 regulates the removal of DNA photoproducts from the genome overall (global nucleotide excision repair), but does not participate in an overlapping pathway that removes damage specifically from the transcribed strand of active genes (transcription-coupled nucleotide excision repair). Here, the highly sensitive ligation-mediated PCR was employed to quantify, at nucleotide resolution, the repair of UVB-induced cyclobutane pyrimidine dimers (CPDs) in genetically p53-deficient Li-Fraumeni skin fibroblasts, as well as in human lung fibroblasts expressing the human papillomavirus (HPV) E6 oncoprotein that functionally inactivates p53. Lung fibroblasts expressing the HPV E7 gene product, which similarly inactivates the retinoblastoma tumor-suppressor protein (pRb), were also investigated. pRb acts downstream of p53 to mediate G(1) arrest, but has no demonstrated role in DNA repair. Relative to normal cells, HPV E6-expressing lung fibroblasts and Li-Fraumeni skin fibroblasts each manifested defective CPD repair along both the transcribed and nontranscribed strands of the p53 and/or c-jun loci. HPV E7-expressing lung fibroblasts also exhibited reduced CPD removal, but only along the nontranscribed strand. Our results provide striking evidence that transcription-coupled repair, in addition to global repair, are p53-dependent in UV-exposed human fibroblasts. Moreover, the observed DNA-repair defect in HPV E7-expressing cells reveals a function for this oncoprotein in HPV-mediated carcinogenesis, and may suggest a role for pRb in global nucleotide excision repair. PMID:10611334

Therrien, J P; Drouin, R; Baril, C; Drobetsky, E A

1999-12-21

339

BAG3 down-modulation sensitizes HPV18(+) HeLa cells to PEITC-induced apoptosis and restores p53.  

PubMed

BAG3 is a multi-functional component of tumor cell pro-survival machinery, and its biological functions have been largely associated to proteasome system. Here, we show that BAG3 down-modulation resulted in reduced cell viability and enhanced PEITC-induced apoptosis largely more extensively in HeLa (HPV18(+)) rather than in C33A (HPV(-)) cervical carcinoma cell lines. Moreover, we demonstrate that BAG3 suppression led to a decrease of viral E6 oncoprotein and a concomitant recovery of p53 tumor suppressor, the best recognized target of E6 for proteasome degradation. E6 and p53 expression were modulated at protein level, since their respective mRNAs were unaffected. Taken together our findings reveal a novel role for BAG3 as host protein contributing to HPV18 E6-activated pro-survival strategies, and suggest a possible relevance of its expression levels in drug/radiotherapy-resistance of HPV18-bearing cervical carcinomas. PMID:25175321

Cotugno, Roberta; Basile, Anna; Romano, Elena; Gallotta, Dario; Belisario, Maria Antonietta

2014-11-28

340

A vaccine conjugate of 'ISCAR' immunocarrier and peptide epitopes of the E7 cervical cancer-associated protein of human papillomavirus type 16 elicits specific Th1- and Th2-type responses in immunized mice in the absence of oil-based adjuvants.  

PubMed Central

TraT protein, known as ISCAR (= Immunostimulatory Carrier), is one of a family of integral membrane proteins (Imps) of Escherichia coli representing powerful carrier molecules which when injected into experimental animals generate substantial antibody and T proliferative responses to molecules conjugated to it. We extend these findings to show that ISCAR functions to stimulate Th1- and Th2-type responses, including specific cytotoxic T cells and tumour protection. We report here that by conjugating to ISCAR a 19mer peptide containing linear B epitopes, a T helper (Th) epitope, and a H-2b-restricted T cytotoxic (CTL) epitope of E7 protein of human papillomavirus type 16 (HPV16), and immunizing C57B1/6 (H-2b) mice, we elicited (i) specific IgG2a and IgG1 antibodies; (ii) IL-2 and IL-4 production by specifically recalled lymph node cells in vitro; (iii) cytotoxic T lymphocytes which specifically killed both E7 peptide-pulsed, and whole E7 gene-transfected tumour target cells; and (iv) in vivo protection against an E7 gene-transfected tumour cell inoculum. These findings have implications for the design of vaccines to stimulate immune responses to endogenously processed target antigens (e.g. tumour-associated antigens) without the unwanted side effects of oil-based adjuvants. In addition they support the case for a E7-targeted therapeutic vaccine for HPV-associated human cervical cancer. PMID:7544248

Tindle, R W; Croft, S; Herd, K; Malcolm, K; Geczy, A F; Stewart, T; Fernando, G J

1995-01-01

341

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E-print Network

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Guedel, Manuel

342

MYCN: from oncoprotein to tumor-associated antigen  

PubMed Central

MYCN is a well-known oncogene over-expressed in different human malignancies including neuroblastoma (NB), rhabdomyosarcoma, medulloblastoma, astrocytoma, Wilms’ tumor, and small cell lung cancer. In the case of NB, MYCN amplification is an established biomarker of poor-prognosis. MYCN belongs to a family of transcription factors (the most important of which is C-MYC) that show a high degree of homology. Down-regulation of MYC protein expression leads to tumor regression in animal models, indicating that MYC proteins represent interesting therapeutic targets. Pre-requisites for a candidate tumor-associated antigen (TAA) to be targeted by immunotherapeutic approaches are the following, (i) expression should be tumor-restricted, (ii) the putative TAA should be up-regulated in cancer cells, and (iii) protein should be processed into immunogenic peptides capable of associating to major histocompatibility complex molecules with high affinity. Indeed, the MYCN protein is not expressed in human adult tissues and up-regulated variably in NB cells, and MYCN peptides capable of associating to HLA-A1 or HLA-A2 molecules with high affinity have been identified. Thus the MYCN protein qualifies as putative TAA in NB. Additional issues that determine the feasibility of targeting a putative TAA with cytotoxic T lymphocytes (CTLs) and will be here discussed are the following, (i) the inadequacy of tumor cells per se to act as antigen-presenting cells witnessed, in the case of NB cells, by the low to absent expression of HLA class I molecules, the lack of co-stimulatory molecules and multiple defects in the HLA class I related antigen processing machinery, and (ii) the immune evasion mechanisms operated by cancer cells to fool the host immune system, such as up-regulation of soluble immunosuppressive molecules (e.g., soluble MICA and HLA-G in the case of NB) or generation of immunosuppressive cells in the tumor microenvironment. A final issue that deserves consideration is the strategy used to generate CTL. PMID:23162796

Pistoia, Vito; Morandi, Fabio; Pezzolo, Annalisa; Raffaghello, Lizzia; Prigione, Ignazia

2012-01-01

343

Biomarkers of gene expression: growth factors and oncoproteins.  

PubMed Central

This article reviews the literature on the application of methods for the detection of growth factors, oncogene proteins, and tumor-suppressor gene proteins in the blood of humans with cancer or who are at risk for the development of cancer. The research summarized here suggests that many of these biomarker assays can be used to distinguish between diseased and nondiseased states and in some instances may be able to predict susceptibility for future disease. Thus, these biomarkers could be valuable tools for monitoring at-risk populations for purposes of disease prevention and control. PMID:9255565

Brandt-Rauf, P W

1997-01-01

344

Oxysterols are allosteric activators of the oncoprotein Smoothened  

PubMed Central

Oxysterols are a class of endogenous signaling molecules that can activate the Hedgehog pathway, which plays critical roles in development, regeneration and cancer. However, it has been unclear how oxysterols influence Hedgehog signaling, including whether their effects are mediated through a protein target or indirectly through effects on membrane properties. To answer this question, we synthesized the enantiomer and an epimer of the most potent oxysterol, 20(S)-hydroxycholesterol. Using these molecules, we show that the effects of oxysterols on Hedgehog signaling are exquisitely stereoselective, consistent with their function through a specific protein target. We present several lines of evidence that this protein target is the 7-pass transmembrane protein Smoothened, a major drug target in oncology. Our work suggests that these enigmatic sterols, which have multiple effects on cell physiology, may act as ligands for signaling receptors and provides a generally applicable framework for probing their mechanism of action. PMID:22231273

Nachtergaele, Sigrid; Mydock, Laurel K.; Krishnan, Kathiresan; Rammohan, Jayan; Schlesinger, Paul H.; Covey, Douglas F.; Rohatgi, Rajat

2011-01-01

345

Epitope specificity and longevity of a vaccine-induced human T cell response against HPV18.  

PubMed

Persistent human papillomavirus (HPV) type 16 and 18 infection can lead to pre-malignant and malignant diseases of the lower genital tract. Several lines of evidence suggest that T cell responses can control HPV infection. However, relative to other human viruses, strong effector memory T cell responses against HPV have been difficult to detect. We used an in vitro stimulation step prior to enzyme-linked immunospot assays to identify IFN-gamma-secreting T cells specific for HPV16 and 18 E6/E7 peptides. This allowed the detection of HPV-specific CD4+ T cells that were not evident in direct ex vivo assays. T cell responses against HPV16 or 18 peptides were detected in healthy volunteers (7/9) and patients with lower genital tract neoplasia (10/20). Importantly, this assay allowed tracking of vaccine-induced T cell responses in nine patients, following inoculation with a live recombinant vaccinia virus (HPV16 and 18 E6/E7, TA-HPV). Novel vaccine-induced T cell responses were demonstrated in five patients, but no clinical responses (lesion regressions) were seen. For one vaccinated patient, the T cell response was mapped to a single dominant HPV18 E7 epitope and this response was sustained for >3 years. Our data suggest that systemic memory T cells against HPV16 and 18, induced naturally or by TA-HPV vaccination, are relatively rare. Nevertheless, the assay system developed allowed estimation of magnitude, epitope specificity, and longevity of vaccine-induced CD4+ T cell responses. This will be useful for vaccine design and measurement of immunological endpoints in clinical trials. PMID:15623547

Smith, Kelly L; Tristram, Amanda; Gallagher, Kathleen M; Fiander, Alison N; Man, Stephen

2005-02-01

346

Human T Cell Leukemia Virus Type I Tax-Induced I?B-? Modulates Tax-Dependent and Tax-Independent Gene Expression in T Cells1  

PubMed Central

Human T cell leukemia virus type I (HTLV-I) is the etiologic agent of adult T cell leukemia (ATL) and various inflammatory disorders including HTLV-I-associated myelopathy/tropical spastic paraparesis. HTLV-I oncoprotein Tax is known to cause permanent activation of many cellular transcription factors including nuclear factor-?B (NF-?B), cyclic adenosine 3?,5?-monophosphate response element-binding protein, and activator protein 1 (AP-1). Here, we show that NF-?B-binding cofactor inhibitor of NF-?B-? (I?B-?) is constitutively expressed in HTLV-I-infected T cell lines and ATL cells, and Tax transactivates the I?B-? gene, mainly through NF-?B. Microarray analysis of I?B-?-expressing uninfected T cells demonstrated that I?B-? induced the expression of NF-?B. and interferon-regulatory genes such as B cell CLL/lymphoma 3 (Bcl3), guanylate-binding protein 1, and signal transducer and activator of transcription 1. The transcriptional activation domain, nuclear localization signal, and NF-?B-binding domain of I?B-? were required for Bcl3 induction, and I?B-? synergistically enhanced Tax-induced Bcl3 transactivation in an NF-?B-dependent manner. Interestingly, I?B-? inhibited Tax-induced NF-?B, AP-1 activation, and HTLV-I transcription. Furthermore, I?B-? interacted with Tax in vitro and this interaction was also observed in an HTLV-I-transformed T cell line. These results suggest that I?B-? modulates Tax-dependent and Tax-independent gene transcription in T cells. The function of I?B-? may be of significance in ATL genesis and pathogenesis of HTLV-I-associated diseases. PMID:24027435

Kimura, Ryuichiro; Senba, Masachika; Cutler, Samuel J; Ralph, Stephen J; Xiao, Gutian; Mori, Naoki

2013-01-01

347

Glucocorticoid-Induced Osteoporosis  

MedlinePLUS

... Glucocorticoid-Induced Osteoporosis Share: Fact Sheet Glucocorticoid-Induced Osteoporosis February, 2012 Download PDFs English Espanol Editors Jens ... Benjamin Z. Leder, MD What is glucocorticoid-induced osteoporosis? Glucocorticoid-induced osteoporosis (GIO) is a condition in ...

348

Induced senescence in HeLa cervical carcinoma cells containing elevated telomerase activity and extended telomeres.  

PubMed

Proliferation of normal somatic human cells in culture is limited by replicative senescence, a growth-arrested state that appears to be triggered by the erosion of telomeres. Tumor cells such as HeLa cervical carcinoma cells, which contain short telomeres, can be induced to undergo senescence by various manipulations including oncogene withdrawal. Repression of the human papillomavirus (HPV) type 18 E6/E7 genes in HeLa cells by the bovine papillomavirus E2 transcriptional regulatory protein results in reactivation of the dormant p53 and p105(Rb) tumor suppressor pathways in these cells, repression of telomerase, and profound growth arrest. Strikingly, the growth-arrested cells rapidly and synchronously acquired numerous characteristics of primary cells undergoing replicative senescence. To explore the role of telomerase and telomere length in induced senescence, we expressed an exogenous hTERT gene, which encodes the catalytic subunit of telomerase, to generate stable HeLa cell clones with elevated telomerase activity and extended telomeres. Expression of the E2 protein in these cells repressed HPV E6/E7 expression, activated tumor suppressor pathways, and induced senescence as assessed by growth arrest, morphological changes, senescence-associated beta-galactosidase expression, and increased autofluorescence. Cells carrying the hTERT gene and control cells displayed identical responses to E2 expression. Therefore, HeLa cell senescence induced by HPV repression is not triggered by short telomeres or low levels of telomerase activity. PMID:11714633

Goodwin, E C; DiMaio, D

2001-11-01

349

Comparison of HPV detection technologies: Hybrid capture 2, PreTect HPV-Proofer and analysis of HPV DNA viral load in HPV16, HPV18 and HPV33 E6/E7 mRNA positive specimens.  

PubMed

Human papillomavirus (HPV) testing using molecular methods in liquid based cytology (LBC) specimens may be useful as an adjunct to cervical screening by cytology. We compared the positivity rate of the commercially available HPV DNA method hybrid capture 2 (hc2) and the commercially available E6/E7 mRNA method PreTect HPV-Proofer in cytological specimens (n=299). LBC specimens collected (n=299) represented the following cervical cytological disease categories: Normal (n=60), borderline nuclear abnormalities (BNA) (n=34), CIN1 (n=121), CIN2 (n=60), CIN3 (n=24). Overall, 69% (205/299) of the cases were positive by hc2 and 38% (112/299) of the cases were positive by PreTect HPV-Proofer. Concordance rates between the two tests were highest in the high-grade cytology cases (CIN2: 67% and CIN3: 83%) and the normal cytology cases (88%) and lowest in the BNA and CIN1 categories (56% and 52%). HPV DNA viral load analyses were carried out on HPV16 (n=55), HPV18 (n=9) and HPV33 (n=13) samples that were positive by PreTect HPV-Proofer. The sensitivity and specificity of PreTect HPV-Proofer and the hc2 DNA test for the detection of high-grade cytology (i.e. CIN2+) were 71.4% and 75.8% vs 100% and 43.7%, respectively. The relatively low detection rate observed by PreTect HPV-Proofer in the whole range of cytological positive cases, combined with a relatively higher specificity and PPV, suggests that PreTect HPV-Proofer may be more useful than hc2 for triage and in predicting high-grade disease. PMID:18955086

Keegan, Helen; Mc Inerney, Jamie; Pilkington, Loretto; Grřnn, Petter; Silva, Ivan; Karlsen, Frank; Bolger, Noel; Logan, Catriona; Furuberg, Liv; O'Leary, John; Martin, Cara

2009-01-01

350

Depletion of the cdk Inhibitor p16INK4a Differentially Affects Proliferation of Established Cervical Carcinoma Cells  

PubMed Central

ABSTRACT Infections with high-risk human papillomaviruses (hrHPV) contribute to cervical carcinoma. The cdk inhibitor and tumor suppressor p16INK4A is consistently upregulated in cervical carcinoma cells for reasons that are poorly understood. We report here that downregulation of p16INK4A gene expression in three different cervical carcinoma cell lines reduced expression of the E7 oncogene, suggesting a positive feedback loop involving E7 and p16INK4A. p16INK4A depletion induced cellular senescence in HeLa but not CaSki and MS-751 cervical carcinoma cells. IMPORTANCE This study demonstrates that the cdk inhibitor p16INK4A, frequently used as surrogate marker for transforming infections by human papillomaviruses of the high-risk group, is required for high-level expression of the E7 oncoproteins of HPV-16, HPV-18, and HPV-45 in cervical carcinoma cells. It is also demonstrated that depletion of p16INK4A induces senescence in HeLa but not CaSki or MS-751 cervical carcinoma cells. PMID:24599991

Pauck, Alexander; Lener, Barbara; Hoell, Monika; Kaiser, Andreas; Kaufmann, Andreas M.; Zwerschke, Werner

2014-01-01

351

Tumor suppressor p16INK4A is necessary for survival of cervical carcinoma cell lines.  

PubMed

The tumor suppressor p16(INK4A) inhibits formation of enzymatically active complexes of cyclin-dependent kinases 4 and 6 (CDK4/6) with D-type cyclins. Oncogenic stress induces p16(INK4A) expression, which in turn triggers cellular senescence through activation of the retinoblastoma tumor suppressor. Subversion of oncogene-induced senescence is a key step during cancer development, and many tumors have lost p16(INK4A) activity by mutation or epigenetic silencing. Human papillomavirus (HPV)-associated tumors express high levels of p16(INK4A) in response to E7 oncoprotein expression. Induction of p16(INK4A) expression is not a consequence of retinoblastoma tumor suppressor inactivation but is triggered by a cellular senescence response and is mediated by epigenetic derepression through the H3K27-specific demethylase (KDM)6B. HPV E7 expression causes an acute dependence on KDM6B expression for cell survival. The p16(INK4A) tumor suppressor is a critical KDM6B downstream transcriptional target and its expression is critical for cell survival. This oncogenic p16(INK4A) activity depends on inhibition of CDK4/CDK6, suggesting that in cervical cancer cells where retinoblastoma tumor suppressor is inactivated, CDK4/CDK6 activity needs to be inhibited in order for cells to survive. Finally, we note that HPV E7 expression creates a unique cellular vulnerability to small-molecule KDM6A/B inhibitors. PMID:24046371

McLaughlin-Drubin, Margaret E; Park, Donglim; Munger, Karl

2013-10-01

352

External Qi of Yan Xin Qigong induces cell death and gene expression alterations promoting apoptosis and inhibiting proliferation, migration and glucose metabolism in small-cell lung cancer cells  

PubMed Central

Small-cell lung cancer (SCLC) is a highly malignant carcinoma with poor long-term survival. Effective treatment remains highly demanded. In the present study, we demonstrated that External Qi of Yan Xin Qigong (YXQ-EQ) exerted potent cytotoxic effect towards SCLC cell line NCI-H82 via induction of apoptosis. Global gene expression profiling identified 39 genes whose expression was altered by YXQ-EQ in NCI-82 cells. Among them, semi-quantitative RT-PCR and real-time qPCR analyses confirmed that the gene expression levels of apoptotic proteins death-associated protein kinase 2 and cell death-inducing DFFA-like effector b were upregulated, whereas that of oncoproteins DEK and MYCL1, cell migration-promoting proteins CD24 and integrin-alpha 9, and glycolytic enzyme aldolase A were downregulated. These findings suggest that YXQ-EQ may exert anticancer effect through modulating gene expression in a way that facilitates cancer cell apoptosis while represses proliferation, metastasis, and glucose metabolism. PMID:22160803

Yan, Xin; Li, Feng; Dozmorov, Igor; Frank, Mark Barton; Dao, Ming; Centola, Michael; Cao, Wei

2013-01-01

353

External Qi of Yan Xin Qigong induces cell death and gene expression alterations promoting apoptosis and inhibiting proliferation, migration and glucose metabolism in small-cell lung cancer cells.  

PubMed

Small-cell lung cancer (SCLC) is a highly malignant carcinoma with poor long-term survival. Effective treatment remains highly demanded. In the present study, we demonstrated that External Qi of Yan Xin Qigong (YXQ-EQ) exerted potent cytotoxic effect towards SCLC cell line NCI-H82 via induction of apoptosis. Global gene expression profiling identified 39 genes whose expression was altered by YXQ-EQ in NCI-82 cells. Among them, semi-quantitative RT-PCR and real-time qPCR analyses confirmed that the gene expression levels of apoptotic proteins death-associated protein kinase 2 and cell death-inducing DFFA-like effector b were upregulated, whereas that of oncoproteins DEK and MYCL1, cell migration-promoting proteins CD24 and integrin-alpha 9, and glycolytic enzyme aldolase A were downregulated. These findings suggest that YXQ-EQ may exert anticancer effect through modulating gene expression in a way that facilitates cancer cell apoptosis while represses proliferation, metastasis, and glucose metabolism. PMID:22160803

Yan, Xin; Li, Feng; Dozmorov, Igor; Frank, Mark Barton; Dao, Ming; Centola, Michael; Cao, Wei; Hu, Dan

2012-04-01

354

Polycyclic Aromatic Hydrocarbons--Induced ROS Accumulation Enhances Mutagenic Potential of T-Antigen From Human Polyomavirus JC  

PubMed Central

Polycyclic aromatic hydrocarbons (PAHs) are the products of incomplete combustion of organic materials, which are present in cigarette smoke, deep-fried food, and in natural crude oil. Since PAH-metabolites form DNA adducts and cause oxidative DNA damage, we asked if these environmental carcinogens could affect transforming potential of the human Polyomavirus JC oncoprotein, T-antigen (JCV T-antigen). We extracted DMSO soluble PAHs from Deepwater Horizon oil spill in the Gulf of Mexico (oil-PAHs), and detected several carcinogenic PAHs. The oil-PAHs were tested in exponentially growing cultures of normal mouse fibroblasts (R508), and in R508 stably expressing JCV T-antigen (R508/T). The oil-PAHs were cytotoxic only at relatively high doses (1:50–1:100 dilution), and at 1:500 dilution the growth and cell survival rates were practically unaffected. This non-toxic dose triggered however, a significant accumulation of reactive oxygen species (ROS), caused oxidative DNA damage and the formation of DNA double strand breaks (DSBs). Although oil-PAHs induced similar levels of DNA damage in R508 and R508/T cells, only T-antigen expressing cells demonstrated inhibition of high fidelity DNA repair by homologous recombination (HRR). In contrast, low-fidelity repair by non-homologous end joining (NHEJ) was unaffected. This potential mutagenic shift between DNA repair mechanisms was accompanied by a significant increase in clonal growth of R508/T cells chronically exposed to low doses of the oil-PAHs. Our results indicate for the first time carcinogenic synergy in which oil-PAHs trigger oxidative DNA damage and JCV T-antigen compromises DNA repair fidelity. PMID:23558788

WILK, ANNA; RSKI, PIOTR WALIGO; LASSAK, ADAM; VASHISTHA, HIMANSHU; LIRETTE, DAVID; TATE, DAVID; ZEA, ARNOLD H.; KOOCHEKPOUR, SHAHRIAR; RODRIGUEZ, PAULO; MEGGS, LEONARD G.; ESTRADA, JOHN J.; OCHOA, AUGUSTO; REISS, KRZYSZTOF

2014-01-01

355

Polycyclic aromatic hydrocarbons-induced ROS accumulation enhances mutagenic potential of T-antigen from human polyomavirus JC.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) are the products of incomplete combustion of organic materials, which are present in cigarette smoke, deep-fried food, and in natural crude oil. Since PAH-metabolites form DNA adducts and cause oxidative DNA damage, we asked if these environmental carcinogens could affect transforming potential of the human Polyomavirus JC oncoprotein, T-antigen (JCV T-antigen). We extracted DMSO soluble PAHs from Deepwater Horizon oil spill in the Gulf of Mexico (oil-PAHs), and detected several carcinogenic PAHs. The oil-PAHs were tested in exponentially growing cultures of normal mouse fibroblasts (R508), and in R508 stably expressing JCV T-antigen (R508/T). The oil-PAHs were cytotoxic only at relatively high doses (1:50-1:100 dilution), and at 1:500 dilution the growth and cell survival rates were practically unaffected. This non-toxic dose triggered however, a significant accumulation of reactive oxygen species (ROS), caused oxidative DNA damage and the formation of DNA double strand breaks (DSBs). Although oil-PAHs induced similar levels of DNA damage in R508 and R508/T cells, only T-antigen expressing cells demonstrated inhibition of high fidelity DNA repair by homologous recombination (HRR). In contrast, low-fidelity repair by non-homologous end joining (NHEJ) was unaffected. This potential mutagenic shift between DNA repair mechanisms was accompanied by a significant increase in clonal growth of R508/T cells chronically exposed to low doses of the oil-PAHs. Our results indicate for the first time carcinogenic synergy in which oil-PAHs trigger oxidative DNA damage and JCV T-antigen compromises DNA repair fidelity. PMID:23558788

Wilk, Anna; Waligórski, Piotr; Lassak, Adam; Vashistha, Himanshu; Lirette, David; Tate, David; Zea, Arnold H; Koochekpour, Shahriar; Rodriguez, Paulo; Meggs, Leonard G; Estrada, John J; Ochoa, Augusto; Reiss, Krzysztof

2013-11-01

356

Spider Mite-Induced (3S)-(E)-Nerolidol Synthase Activity in Cucumber and Lima Bean. The First Dedicated Step in Acyclic C11-Homoterpene Biosynthesis1  

PubMed Central

Many plant species respond to herbivory with de novo production of a mixture of volatiles that attracts carnivorous enemies of the herbivores. One of the major components in the blend of volatiles produced by many different plant species in response to herbivory by insects and spider mites is the homoterpene 4,8-dimethyl-1,3(E),7-nonatriene. One study (J. Donath, W. Boland [1995] Phytochemistry 39: 785–790) demonstrated that a number of plant species can convert the acyclic sesquiterpene alcohol (3S)-(E)-nerolidol to this homoterpene. Cucumber (Cucumis sativus L.) and lima bean (Phaseolus lunatus L.) both produce 4,8-dimethyl-1,3(E),7-nonatriene in response to herbivory. We report the presence in cucumber and lima bean of a sesquiterpene synthase catalyzing the formation of (3S)-(E)-nerolidol from farnesyl diphosphate. The enzyme is inactive in uninfested cucumber leaves, slightly active in uninfested lima bean leaves, and strongly induced by feeding of the two-spotted spider mite (Tetranychus urticae Koch) on both plant species, but not by mechanical wounding. The activities of the (3S)-(E)-nerolidol synthase correlated well with the levels of release of 4,8-dimethyl-1,3(E),7-nonatriene from the leaves of the different treatments. Thus, (3S)-(E)-nerolidol synthase is a good candidate for a regulatory role in the release of the important signaling molecule 4,8-dimethyl-1,3(E),7-nonatriene. PMID:10482672

Bouwmeester, Harro J.; Verstappen, Francel W.A.; Posthumus, Maarten A.; Dicke, Marcel

1999-01-01

357

Ras-induced ROS upregulation affecting cell proliferation is connected with cell type-specific alterations of HSF1/SESN3/p21Cip1/WAF1 pathways.  

PubMed

Oncogenes of the RAS family regulate many of the cell's activities, including proliferation, survival and differentiation. Activating mutations in these genes are common events for many types of cancer. One of the contradictory points concerning the biological significance of Ras activation is its dual effect (pro- or anti-proliferative) on cell reproduction. One of mechanisms by which Ras proteins influence cell growth is a regulation of intracellular level of reactive oxygen species (ROS), second messengers affecting variety of cellular processes including cell proliferation. Recently it was shown that repression of SESN1 and SESN3 genes, whose protein products control regeneration of peroxiredoxins, can play a critical role in Ras-induced ROS upregulation. In the present study we have found that Ras-induced repression of SESN3 expression and ROS upregulation is mediated via the modifications of transcriptional activity of HSF1. Interestingly, mutant Ras overexpression altered the activity of HSF1 in opposite directions in different cell contexts, in particular in human normal fibroblasts and HaCaT immortalized keratinocytes, but these opposite changes caused similar repression of SESN3 expression followed by elevation of ROS content and inhibition of cell proliferation in corresponding cell types. The inhibitory effect on cell proliferation was mediated by upregulation of p21(Cip1/WAF1). Thus, HSF1/SESN3/ROS/p21(Cip1/WAF1)-mediated deceleration of cell growth may contribute to cell defense systems protecting the organism from excessive proliferation of cells that overexpress activated Ras oncoproteins. PMID:23388456

Zamkova, Maria; Khromova, Natalia; Kopnin, Boris P; Kopnin, Pavel

2013-03-01

358

Potent Anti-Tumor Effect Generated by a Novel Human Papillomavirus (HPV) Antagonist Peptide Reactivating the pRb/E2F Pathway  

PubMed Central

Human papillomavirus type 16 (HPV16) E7 is a viral oncoprotein believed to play a major role in cervical cancer. In this study, an antagonist peptide against HPV16E7 protein was first identified from screening the c7c phage display peptide library. The binding specificity and affinity of the selected peptide to HPV16E7 were tested by competitive enzyme-linked immunosorbent assay (ELISA). The antagonist peptide showed obvious anti-tumor efficacy both in cell lines and animal tumor models. Significant cell proliferation inhibition with high specificity was noted when HPV16-positive cells were treated with the peptide. This anti-tumor efficacy was resulted from overriding the activities of HPV16E7 and reactivating the pRb/E2F pathway, as shown by a series of experiments. Flow cytometry analysis revealed that the selected peptide induced G1 arrest in a dose-dependent manner. Competitive ELISA, pull down, and Co-IP experiments indicated that the selected peptide disrupted the interaction between HPV16E7 and pRb proteins both in vitro and in vivo. Luciferase reporter assay verified that transcription activities of E2F were suppressed by the peptide through restoration of pRb. RT-PCR and Western blot revealed that it reduced cyclins A, D1, and E1 expression, and led to HPV16E7 protein degradation, but pRb protein stabilization. The current study suggests that this specific peptide may serve as a potential therapeutic agent for HPV16-positive cervical cancer. PMID:21423621

Guo, Cai-ping; Liu, Ke-wei; Luo, Hai-bo; Chen, Hong-bo; Zheng, Yi; Sun, Shen-nan; Zhang, Qian; Huang, Laiqiang

2011-01-01

359

12/08/2006 11:12 AMScientific American: Scientific American 50 Page 1 of 1http://www.sciam.com/print_version.cfm?articleID=CA0C1B39-E7F2-99DF-3E9C70D833C09DD4  

E-print Network

12/08/2006 11:12 AMScientific American: Scientific American 50 Page 1 of 1http://www.sciam.com/print_version.cfm?articleID=CA0C1B39-E7F2-99DF-3E9C70D833C09DD4 November 12, 2006 Scientific American 50 By The Editors A group of the 2006 SCIENTIFIC AMERICAN 50 awards. These accomplishments go beyond invoking the Invisible Man. Drawn

Lindquist, Susan

360

Roles of the PDZ domain-binding motif of the human papillomavirus type 16 E6 on the immortalization and differentiation of primary human foreskin keratinocytes.  

PubMed

A number of PDZ domain-containing proteins have been identified as binding partners for the oncoprotein E6 of the high-risk type human papillomaviruses (HPVs). These include hDlg, hScrib, MAGI1, MAGI2, and MAGI3, MUPP1, 14-3-3zeta, Na/H exchange regulatory factor 1, PTPN13, TIP-2/GIPC, Tip-1, and PATJ. The PDZ domain-binding motif (-X-T-X-V) at the carboxy terminus of E6 is essential for targeting PDZ proteins for proteasomal degradation. However, contribution of degradation of PDZ proteins by E6 to HPV-induced oncogenesis is still controversial. In order to clarify potential roles of molecular interactions between high-risk HPV E6 and one of best characterized PDZ proteins, hDlg in HPV-induced transformation, we used a retroviral infection system to overexpress HPV16 E7 gene alone or together with either HPV16 E6 wild type or E6 mutant gene lacking the PDZ domain-binding motif and investigated the effect of mutating the PDZ domain-binding motif of E6 on the immortalization and differentiation of human foreskin keratinocytes (HFKs) by the high-risk type HPV E6 and E7. Although the PDZ domain-binding motif of E6 was found to be required for the efficient growth of HFKs, it was not necessary for the E6 and E7-induced immortalization of HFKs. Furthermore, the overexpression of E6 and E7 neither induced degradation nor altered cellular localization of hDlg in undifferentiated or differentiated HFKs. These data indicate that the PDZ domain-binding motif of E6 contributes to the efficient cellular growth through mechanisms other than degradation and changes in the subcellular localizations of hDlg. PMID:24293186

Choi, Moonju; Lee, Sungjin; Choi, Taekyu; Lee, Choongho

2014-04-01

361

Curcumin-induced Aurora-A suppression not only causes mitotic defect and cell cycle arrest but also alters chemosensitivity to anticancer drugs.  

PubMed

Overexpression of oncoprotein Aurora-A increases drug resistance and promotes lung metastasis of breast cancer cells. Curcumin is an active anticancer compound in turmeric and curry. Here we observed that Aurora-A protein and kinase activity were reduced in curcumin-treated human breast chemoresistant nonmetastatic MCF-7 and highly metastatic cancer MDA-MB-231 cells. Curcumin acts in a similar manner to Aurora-A small interfering RNA (siRNA), resulting in monopolar spindle formation, S and G2/M arrest, and cell division reduction. Ectopic Aurora-A extinguished the curcumin effects. The anticancer effects of curcumin were enhanced by Aurora-A siRNA and produced additivity and synergism effects in cell division and monopolar phenotype, respectively. Combination treatment with curcumin overrode the chemoresistance to four Food and Drug Administration (FDA)-approved anticancer drugs (ixabepilone, cisplatin, vinorelbine, or everolimus) in MDA-MB-231 cells, which was characterized by a decrease in cell viability and the occurrence of an additivity or synergy effect. Ectopic expression of Aurora-A attenuated curcumin-enhanced chemosensitivity to these four tested drugs. A similar benefit of curcumin was observed in MCF-7 cells treated with ixabepilone, the primary systemic therapy to patients with invasive breast cancer (stages IIA-IIIB) before surgery. Antagonism effect was observed when MCF-7 cells were treated with curcumin plus cisplatin, vinorelbine or everolimus. Curcumin-induced enhancement in chemosensitivity was paralleled by significant increases (additivity or synergy effect) in apoptosis and cell cycle arrest at S and G2/M phases, the consequences of Aurora-A inhibition. These results suggest that a combination of curcumin with FDA-approved anticancer drugs warrants further assessment with a view to developing a novel clinical treatment for breast cancer. PMID:24613085

Ke, Ching-Shiun; Liu, Hsiao-Sheng; Yen, Cheng-Hsin; Huang, Guan-Cheng; Cheng, Hung-Chi; Huang, Chi-Ying F; Su, Chun-Li

2014-05-01

362

FTY720 Induces Apoptosis of M2 Subtype Acute Myeloid Leukemia Cells by Targeting Sphingolipid Metabolism and Increasing Endogenous Ceramide Levels  

PubMed Central

The M2 subtype Acute Myeloid Leukemia (AML-M2) with t(8;21) represents an unmet challenge because of poor clinical outcomes in a sizable portion of patients. In this study,we report that FTY720 (Fingolimod), a sphingosine analogue and an FDA approved drug for treating of multiple sclerosis, shows antitumorigenic activity against the Kasumi-1 cell line, xenograft mouse models and leukemic blasts isolated from AML-M2 patients with t(8;21) translocation. Primary investigation indicated that FTY720 caused cell apoptosis through caspases and protein phosphatase 2A (PP2A) activation. Transcriptomic profiling further revealed that FTY720 treatment could upregulate AML1 target genes and interfere with genes involved in ceramide synthesis. Treatment with FTY720 led to the elimination of AML1-ETO oncoprotein and caused cell cycle arrest. More importantly, FTY720 treatment resulted in rapid and significant increase of pro-apoptotic ceramide levels, determined by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry based lipidomic approaches. Structural simulation model had also indicated that the direct binding of ceramide to inhibitor 2 of PP2A (I2PP2A) could reactivate PP2A and cause cell death. This study demonstrates, for the first time, that accumulation of ceramide plays a central role in FTY720 induced cell death of AML-M2 with t(8;21). Targeting sphingolipid metabolism by using FTY720 may provide novel insight for the drug development of treatment for AML-M2 leukemia. PMID:25050888

Li, Lianchun; Liu, Yuan-Fang; Wang, Jiang; Liu, Hong; Song, Heng; Jiang, Hualiang; Chen, Sai-Juan; Luo, Cheng; Li, Keqin Kathy

2014-01-01

363

CD8+ T Cells Targeting A Single Immunodominant Epitope Are Sufficient for Elimination of Established SV40 T Antigen-Induced Brain Tumors1  

PubMed Central

Immunotherapy of established solid tumors is rarely achieved and the mechanisms leading to success remain to be elucidated. We previously showed that extended control of advanced-stage autochthonous brain tumors is achieved following adoptive transfer of naďve C57BL/6 splenocytes into sublethally irradiated line SV11 mice expressing the SV40 T antigen (T Ag) oncoprotein, and was associated with in vivo priming of CD8+ T cells (TCD8) specific for the dominant epitope IV (T Ag residues 404–411). Using donor lymphocytes derived from mice that are tolerant to epitope IV or a newly characterized transgenic mouse line expressing an epitope IV-specific T cell receptor, we show that epitope IV-specific TCD8 are a necessary component of the donor pool and that purified naďve epitope IV-specific TCD8 are sufficient to promote complete and rapid regression of established tumors. While transfer of naďve TCR-IV cells alone induced some initial tumor regression, increased survival of tumor-bearing mice required prior conditioning of the host with a sublethal dose of gamma irradiation and was associated with complete tumor eradication. Regression of established tumors was associated with rapid accumulation of TCR-IV T cells within the brain following initial priming against the endogenous T Ag in the peripheral lymphoid organs. In addition, persistence of functional TCR-IV cells in both the brain and peripheral lymphoid organs was associated with long-term tumor-free survival. Finally, we show that production of IFN?, but not perforin or TNF?, by the donor lymphocytes is critical for control of autochthonous brain tumors. PMID:18768900

Tatum, Angela M.; Mylin, Lawrence M.; Bender, Susan J.; Fischer, Matthew A.; Vigliotti, Beth A.; Tevethia, M. Judith; Tevethia, Satvir S.; Schell, Todd D.

2008-01-01

364

Inhibition of mammalian target of rapamycin signaling by everolimus induces senescence in adult T-cell leukemia/lymphoma and apoptosis in peripheral T-cell lymphomas.  

PubMed

HTLV-I-associated adult T-cell leukemia/lymphoma (ATL) and human T-cell lymphotropic virus type I (HTLV-I)-negative peripheral T-cell lymphomas carry poor prognosis mainly because of acquired resistance to chemotherapy. We have shown that this disease is responsive to the combination of zidovudine and interferon-?. However, long-term maintenance therapy with this combination is associated with side effects affecting patient quality of life and hence more tolerated alternatives are needed. In this submission, we explored the effect of the mammalian target of rapamycin (mTOR) complex-1 (mTORC1) inhibitor everolimus (RAD001) on ATL and HTLV-negative malignant T-cell lines. We demonstrate that, at clinically achievable concentrations, long-term treatment with everolimus resulted in a dramatic inhibitory effect on the growth of HTLV-I-positive and -negative malignant T-cells, while normal resting or activated T-lymphocytes were resistant. Everolimus specifically induced oncoprotein Tax degradation and senescence in ATL cells and cell cycle arrest and apoptosis in HTLV-I-negative malignant T-cells. Everolimus-mediated apoptosis was also associated with an upregulation of p53 upregulated modulator of apoptosis (PUMA-?) proteins, an increase in Bax proteins and downregulation of Bcl-x(L) proteins in all tested HTLV-I-positive and -negative malignant cell lines. These results support a therapeutic role for everolimus, particularly as long-term maintenance therapy in patients with ATL and other HTLV-I-negative peripheral T-cell lymphomas. PMID:21064094

Darwiche, Nadine; Sinjab, Ansam; Abou-Lteif, Ghada; Chedid, Mirella Bou; Hermine, Olivier; Dbaibo, Ghassan; Bazarbachi, Ali

2011-08-15

365

An alternative splice form of Mdm2 induces p53-independent cell growth and tumorigenesis  

Microsoft Academic Search

The Mdm2 gene is amplified in approximately one-third of human sarcomas and overexpressed in a variety of other human cancers. Mdm2 functions as an oncoprotein, in part, by acting as a negative regulator of the p53 tumor suppressor protein. Multiple spliced forms of Mdm2 transcripts have been observed in human tumors; however, the contribution of these variant transcripts to tumorigenesis

Heather Anne Steinman; Ezra Burstein; Christopher J. Lengner; Joseph R. Gosselin; German A. Pihan; Colin S. Duckett; Stephen N. Jones

2003-01-01