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Yuji Yaginuma - One of the best experts on this subject based on the ideXlab platform.
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Abstract 4049: Conserved region 2 of Human Papilloma Virus 18 Protein E7 is required for E7 binding to centromere Protein C
Tumor Biology, 2016Co-Authors: Aoi Tokuda, Shoko Takahashi, Masafumi Yoshimoto, Yuji YaginumaAbstract:The molecular genetics of cervical cancer have not been thoroughly elucidated, despite the fact that cervical cancer is responsible for the deaths of over 250,000 women annually worldwide. Infection with human papillomaviruses (HPVs) is linked to the pathogenesis of a variety of human diseases, including genital warts, laryngeal papillomas, and most notably, cervical cancer. Recently HPV infection was reported to be associated with head and neck cancers.High-risk human papillomaviruses (HPVs) are etiologically linked to human cervical and oral cancers. HPV infection leads to aneuploidy, a numerical chromosomal aberration caused by dysregulation of chromosomal segregation. We found that high-risk HPV18 and HPV58 E7 Proteins bind to centromere Protein C (CENP-C), a component of the kinetochore that is essential for proper chromosomal segregation. Low-risk HPV4, HPV6, and HPV11 E7s do not bind to CENP-C. The PxDLLCxE sequence in conserved region 2 (CR2) of HPV18 E7 is required for E7 binding to CENP-C. Our results indicate that differences in the ability of high- and low-risk HPV E7s to bind to CENP-C reflect the different oncogenic potentials of high- and low-risk type HPVs.We demonstrated that the E7 Proteins from low-risk HPVs do not bind to CENP-C, and that the PxDLLCxE sequence in conserved region 2 of the HPV18 E7 Protein is required for E7 binding to CENP-C. CENP-C is a component of the inner kinetochore, and as such, it plays an essential role in proper chromosome segregation, mitotic checkpoint function, and kinetochore assembly. Therefore, we hypothesize that differences in the capability of various E7s from low- and high-risk type HPVs to bind to CENP-C reflect the different oncogenic potential of high- and low-risk type HPVs. Citation Format: Aoi Tokuda, Shoko Takahashi, Masafumi Yoshimoto, Yuji Yaginuma. Conserved region 2 of Human Papilloma Virus 18 Protein E7 is required for E7 binding to centromere Protein C. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4049.
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The PxDLLCxE Sequence in Conserved Region 2 of Human Papilloma Virus 18 Protein E7 Is Required for E7 Binding to Centromere Protein C
Oncology, 2012Co-Authors: Yuji Yaginuma, Masafumi Yoshimoto, Ayami Eguchi, Katsuhiro OgawaAbstract:High-risk human papillomaviruses (HPVs) are etiologically linked to human cervical and oral cancers. HPV infection leads to aneuploidy, a numerical chromosomal aberration caused by dysregulation of chromosomal segregation. We found that high-risk HPV18 and HPV58 E7 Proteins bind to centromere Protein C (CENP-C), a component of the kinetochore that is essential for proper chromosomal segregation. Low-risk HPV4, HPV6, and HPV11 E7s do not bind to CENP-C. The PxDLLCxE sequence in conserved region 2 (CR2) of HPV18 E7 is required for E7 binding to CENP-C. Our results indicate that differences in the ability of high- and low-risk HPV E7s to bind to CENP-C reflect the different oncogenic potentials of high- and low-risk type HPVs.
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Characterization of physical binding between human papillomavirus 18 Protein E7 and centromere Protein C.
Oncology, 2010Co-Authors: Yuji Yaginuma, Kinya Yoda, Katsuhiro OgawaAbstract:Human papillomaviruses (HPVs) have been linked to a variety of human diseases, most notably cancer of the cervix. In the majority of cases, HPV Proteins E6 and E7 are continuously expressed and bind a variety of cellular Proteins. The precise mechanism of HPV-induced carcinogenesis has not been fully elucidated; therefore, we attempted to identify the cellular Proteins that interact with HPV18 E7 to better understand the function of this important Protein. Using yeast 2-hybrid screening, we identified centromere Protein C (CENP-C) as one of the Proteins that interact with HPV18 E7. CENP-C interacted with E7 from HPV18 but not from HPV11. The CR2 domain of HPV18 E7 and the C-terminal region of CENP-C were found to be involved in the binding of these Proteins. CENP-C is a component of the inner kinetochore and plays an essential role in proper chromosome segregation, mitotic checkpoint function, and kinetochore assembly. HPV18 E7-CENP-C binding may therefore impair centromere function, in turn causing cancers. We speculate that altered function of CENP-C as a result of interactions with HPV E7 may be associated with chromosomal abnormalities in HPV18-positive cancers.
R. C. Stocco Dos Santos - One of the best experts on this subject based on the ideXlab platform.
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Quercetin induces structural chromosomal aberrations and uncommon rearrangements in bovine cells transformed by the E7 Protein of bovine papillomavirus type 4
Veterinary and Comparative Oncology, 2003Co-Authors: A. C. S. M. Leal, O. P. Ferraz, Carlos Carvalho, Antonio Carlos De Freitas, R. G. Beniston, Willy Beçak, Maria Saveria Campo, R. C. Stocco Dos SantosAbstract:: Bovine papillomavirus type 4 (BPV-4) and bracken fern are cofactors in the carcinogenesis of the upper gastrointestinal (GI) tract of cattle. An experimental in vitro model system has been developed to analyse the co-operation between the viral transforming Protein E7, the cellular ras oncogene and quercetin, one of the mutagens of bracken fern, during neoplastic progression of primary bovine cells. We now report cytogenetic studies of these cells at different stages of malignant transformation: parental primary non-transformed PalF cells; E7R cells transformed by BPV-4 E7 and activated ras but not tumorigenic, and tumorigenic E7Q cells derived from E7R cells after treatment with quercetin. All cell lines presented increased numbers of aneuploid cells. The rate of structural chromosomal aberrations observed was increased in transformed cells. In addition, E7Q cells showed chromosomes with peculiar rearrangements, which resulted in metacentric and submetacentric marker chromosomes, with an increase in the mean chromosome arm number. These markers were the products of possible centric fusions. These aberrations and rearrangements were distributed throughout the karyotype, no specific chromosome was involved and the heterochromatic centromeric regions appeared to be preserved.
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Quercetin induces structural chromosomal aberrations and uncommon rearrangements in bovine cells transformed by the E7 Protein of bovine papillomavirus type 4
Veterinary and comparative oncology, 2003Co-Authors: A. C. S. M. Leal, O. P. Ferraz, Antonio Carlos De Freitas, R. G. Beniston, Willy Beçak, Maria Saveria Campo, Camila Ferreira De Carvalho, R. C. Stocco Dos SantosAbstract:Bovine papillomavirus type 4 (BPV-4) and bracken fern are cofactors in the carcinogenesis of the upper gastrointestinal (GI) tract of cattle. An experimental in vitro model system has been developed to analyse the co-operation between the viral transforming Protein E7, the cellular ras oncogene and quercetin, one of the mutagens of bracken fern, during neoplastic progression of primary bovine cells. We now report cytogenetic studies of these cells at different stages of malignant transformation: parental primary non-transformed PalF cells; E7R cells transformed by BPV-4 E7 and activated ras but not tumorigenic, and tumorigenic E7Q cells derived from E7R cells after treatment with quercetin. All cell lines presented increased numbers of aneuploid cells. The rate of structural chromosomal aberrations observed was increased in transformed cells. In addition, E7Q cells showed chromosomes with peculiar rearrangements, which resulted in metacentric and submetacentric marker chromosomes, with an increase in the mean chromosome arm number. These markers were the products of possible centric fusions. These aberrations and rearrangements were distributed throughout the karyotype, no specific chromosome was involved and the heterochromatic centromeric regions appeared to be preserved.
Katsuhiro Ogawa - One of the best experts on this subject based on the ideXlab platform.
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The PxDLLCxE Sequence in Conserved Region 2 of Human Papilloma Virus 18 Protein E7 Is Required for E7 Binding to Centromere Protein C
Oncology, 2012Co-Authors: Yuji Yaginuma, Masafumi Yoshimoto, Ayami Eguchi, Katsuhiro OgawaAbstract:High-risk human papillomaviruses (HPVs) are etiologically linked to human cervical and oral cancers. HPV infection leads to aneuploidy, a numerical chromosomal aberration caused by dysregulation of chromosomal segregation. We found that high-risk HPV18 and HPV58 E7 Proteins bind to centromere Protein C (CENP-C), a component of the kinetochore that is essential for proper chromosomal segregation. Low-risk HPV4, HPV6, and HPV11 E7s do not bind to CENP-C. The PxDLLCxE sequence in conserved region 2 (CR2) of HPV18 E7 is required for E7 binding to CENP-C. Our results indicate that differences in the ability of high- and low-risk HPV E7s to bind to CENP-C reflect the different oncogenic potentials of high- and low-risk type HPVs.
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Characterization of physical binding between human papillomavirus 18 Protein E7 and centromere Protein C.
Oncology, 2010Co-Authors: Yuji Yaginuma, Kinya Yoda, Katsuhiro OgawaAbstract:Human papillomaviruses (HPVs) have been linked to a variety of human diseases, most notably cancer of the cervix. In the majority of cases, HPV Proteins E6 and E7 are continuously expressed and bind a variety of cellular Proteins. The precise mechanism of HPV-induced carcinogenesis has not been fully elucidated; therefore, we attempted to identify the cellular Proteins that interact with HPV18 E7 to better understand the function of this important Protein. Using yeast 2-hybrid screening, we identified centromere Protein C (CENP-C) as one of the Proteins that interact with HPV18 E7. CENP-C interacted with E7 from HPV18 but not from HPV11. The CR2 domain of HPV18 E7 and the C-terminal region of CENP-C were found to be involved in the binding of these Proteins. CENP-C is a component of the inner kinetochore and plays an essential role in proper chromosome segregation, mitotic checkpoint function, and kinetochore assembly. HPV18 E7-CENP-C binding may therefore impair centromere function, in turn causing cancers. We speculate that altered function of CENP-C as a result of interactions with HPV E7 may be associated with chromosomal abnormalities in HPV18-positive cancers.
A. C. S. M. Leal - One of the best experts on this subject based on the ideXlab platform.
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Quercetin induces structural chromosomal aberrations and uncommon rearrangements in bovine cells transformed by the E7 Protein of bovine papillomavirus type 4
Veterinary and Comparative Oncology, 2003Co-Authors: A. C. S. M. Leal, O. P. Ferraz, Carlos Carvalho, Antonio Carlos De Freitas, R. G. Beniston, Willy Beçak, Maria Saveria Campo, R. C. Stocco Dos SantosAbstract:: Bovine papillomavirus type 4 (BPV-4) and bracken fern are cofactors in the carcinogenesis of the upper gastrointestinal (GI) tract of cattle. An experimental in vitro model system has been developed to analyse the co-operation between the viral transforming Protein E7, the cellular ras oncogene and quercetin, one of the mutagens of bracken fern, during neoplastic progression of primary bovine cells. We now report cytogenetic studies of these cells at different stages of malignant transformation: parental primary non-transformed PalF cells; E7R cells transformed by BPV-4 E7 and activated ras but not tumorigenic, and tumorigenic E7Q cells derived from E7R cells after treatment with quercetin. All cell lines presented increased numbers of aneuploid cells. The rate of structural chromosomal aberrations observed was increased in transformed cells. In addition, E7Q cells showed chromosomes with peculiar rearrangements, which resulted in metacentric and submetacentric marker chromosomes, with an increase in the mean chromosome arm number. These markers were the products of possible centric fusions. These aberrations and rearrangements were distributed throughout the karyotype, no specific chromosome was involved and the heterochromatic centromeric regions appeared to be preserved.
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Quercetin induces structural chromosomal aberrations and uncommon rearrangements in bovine cells transformed by the E7 Protein of bovine papillomavirus type 4
Veterinary and comparative oncology, 2003Co-Authors: A. C. S. M. Leal, O. P. Ferraz, Antonio Carlos De Freitas, R. G. Beniston, Willy Beçak, Maria Saveria Campo, Camila Ferreira De Carvalho, R. C. Stocco Dos SantosAbstract:Bovine papillomavirus type 4 (BPV-4) and bracken fern are cofactors in the carcinogenesis of the upper gastrointestinal (GI) tract of cattle. An experimental in vitro model system has been developed to analyse the co-operation between the viral transforming Protein E7, the cellular ras oncogene and quercetin, one of the mutagens of bracken fern, during neoplastic progression of primary bovine cells. We now report cytogenetic studies of these cells at different stages of malignant transformation: parental primary non-transformed PalF cells; E7R cells transformed by BPV-4 E7 and activated ras but not tumorigenic, and tumorigenic E7Q cells derived from E7R cells after treatment with quercetin. All cell lines presented increased numbers of aneuploid cells. The rate of structural chromosomal aberrations observed was increased in transformed cells. In addition, E7Q cells showed chromosomes with peculiar rearrangements, which resulted in metacentric and submetacentric marker chromosomes, with an increase in the mean chromosome arm number. These markers were the products of possible centric fusions. These aberrations and rearrangements were distributed throughout the karyotype, no specific chromosome was involved and the heterochromatic centromeric regions appeared to be preserved.
Ian H. Frazer - One of the best experts on this subject based on the ideXlab platform.
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Human papillomavirus 16 E7 Protein inhibits interferon-γ-mediated enhancement of keratinocyte antigen processing and T-cell lysis.
The FEBS journal, 2011Co-Authors: Fang Zhou, Graham R. Leggatt, Ian H. FrazerAbstract:Infection of epithelium with human papillomavirus (HPV) 16 is generally prolonged, suggesting an ineffective virus-specific immune response, and prolonged infection promotes anogenital cancer. To determine whether poor antigen presentation by HPV-infected keratinocytes (KCs) contributes to prolonged HPV infection, KCs and KCs expressing HPV 16 E7 Protein (E7-KCs) were compared for susceptibility to T-cell-mediated lysis directed to ovalbumin (OVA) processed for presentation by the KCs. Interferon (IFN)-gamma efficiently enhanced susceptibility to lysis of KCs presenting OVA, but not of E7-KCs similarly presenting OVA. E7-KCs also exhibited impaired IFN-gamma-induced upregulation of transcription of major histocompatibility complex class I antigen processing and presentation-associated genes, and of membrane SIINFEKL-H-2Kb complexes. Thus, expression of HPV 16 E7 Protein in KCs may inhibit enhancement by IFN-gamma of KC sensitivity to T-cell lysis, by impairing antigen presentation.
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expression purification and immunological characterization of the transforming Protein E7 from cervical cancer associated human papillomavirus type 16
Clinical and Experimental Immunology, 1999Co-Authors: Germain J. P. Fernando, B. Murray, Jian Zhou, Ian H. FrazerAbstract:E7 is the major oncogenic Protein produced in cervical cancer-associated human papillomavirus type 16 (HPV16). This Protein was expressed in Escherichia coli as a glutathione-S-transferase (GST) fusion Protein. E7-enriched inclusion bodies were collected from bacterial lysates, were solubilized in 10 M urea, and the Protein was purified using anion exchange column chromatography. After removal of endotoxin with serial Triton X-114 extractions, material of high purity (about 90%) was obtained, which is suitable for use in a human clinical trial. This material was immunogenic, and when used as a vaccine, protected mice against challenge with an HPV16 E7 DNA transfected tumour cell line. Based on this observation, the E7GST fusion Protein is currently being used in a human clinical trial of a vaccine against HPV16-induced cervical cancer. This fusion Protein could be cleaved with thrombin to remove the GST fusion part and further purified by preparative SDS gel electrophoresis to obtain free E7 with > 98% purity.
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Expression, purification and immunological characterization of the transforming Protein E7, from cervical cancer‐associated human papillomavirus type 16
Clinical and experimental immunology, 1999Co-Authors: Germain J. P. Fernando, B. Murray, Jian Zhou, Ian H. FrazerAbstract:E7 is the major oncogenic Protein produced in cervical cancer-associated human papillomavirus type 16 (HPV16). This Protein was expressed in Escherichia coli as a glutathione-S-transferase (GST) fusion Protein. E7-enriched inclusion bodies were collected from bacterial lysates, were solubilized in 10 M urea, and the Protein was purified using anion exchange column chromatography. After removal of endotoxin with serial Triton X-114 extractions, material of high purity (about 90%) was obtained, which is suitable for use in a human clinical trial. This material was immunogenic, and when used as a vaccine, protected mice against challenge with an HPV16 E7 DNA transfected tumour cell line. Based on this observation, the E7GST fusion Protein is currently being used in a human clinical trial of a vaccine against HPV16-induced cervical cancer. This fusion Protein could be cleaved with thrombin to remove the GST fusion part and further purified by preparative SDS gel electrophoresis to obtain free E7 with > 98% purity.
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Identification of B-epitopes in the human papillomavirus 18 E7 open reading frame Protein.
Journal of immunology (Baltimore Md. : 1950), 1990Co-Authors: Linda A. Selvey, Robert W. Tindle, H M Geysen, C J Haller, J A Smith, Ian H. FrazerAbstract:A panel of murine mAb raised against a MS2 replicase/HPV 18 E7 fusion Protein included 23 reactive by ELISA with HPV 18 E7 determinants. A total of 19 of the 23 recognized linear epitopes in the N-terminal region of the E7 molecule, while the other four were deduced by binding inhibition assays to recognize conformational determinants in this region. All tested antibodies precipitated a 14-kDa peptide doublet that corresponded with the predicted size of the E7 Protein, from HeLa cells, but not from HPV 16 E7 containing CaSki cells. HPV 18 E7 Protein was detected by immunolabeling with electron microscopy in both the nucleus and the cytoplasm of HeLa cells with the greater proportion occurring in the cytoplasm. No antibody reacted specifically by indirect immunofluorescence with HeLa cells. Weak cross-reactivity of some mAb with the E6 MS2-replicase fusion Protein of HPV 16 was detected by ELISA, but no Protein of the appropriate size was immunoprecipitated from CaSki cells. It is concluded that the B cell epitopes on the HPV 18 E7 transforming Protein are located in the N-terminal region of the molecule and that some are weakly cross-reactive with HPV 16 E6 Protein. E7 Protein is either present in HeLa cells at a concentration too low to be detected by indirect immunofluorescence, or the N-terminal epitopes are masked by Protein conformation or interaction with cellular or other viral components.
