Science.gov

Sample records for e7 oncoprotein induces

  1. The human papillomavirus E7 oncoprotein

    SciTech Connect

    McLaughlin-Drubin, Margaret E. Muenger, Karl

    2009-02-20

    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.

  2. The HPV16 E7 Oncoprotein Disrupts Dendritic Cell Function and Induces the Systemic Expansion of CD11b(+)Gr1(+) Cells in a Transgenic Mouse Model.

    PubMed

    Damian-Morales, Gabriela; Serafín-Higuera, Nicolás; Moreno-Eutimio, Mario Adán; Cortés-Malagón, Enoc M; Bonilla-Delgado, José; Rodríguez-Uribe, Genaro; Ocadiz-Delgado, Rodolfo; Lambert, Paul F; Gariglio, Patricio

    2016-01-01

    Objective. The aim of this study was to analyze the effects of the HPV16 E7 oncoprotein on dendritic cells (DCs) and CD11b(+)Gr1(+) cells using the K14E7 transgenic mouse model. Materials and Methods. The morphology of DCs was analyzed in male mouse skin on epidermal sheets using immunofluorescence and confocal microscopy. Flow cytometry was used to determine the percentages of DCs and CD11b(+)Gr1(+) cells in different tissues and to evaluate the migration of DCs. Results. In the K14E7 mouse model, the morphology of Langerhans cells and the migratory activity of dendritic cells were abnormal. An increase in CD11b(+)Gr1(+) cells was observed in the blood and skin of K14E7 mice, and molecules related to CD11b(+)Gr1(+) chemoattraction (MCP1 and S100A9) were upregulated. Conclusions. These data suggest that the HPV16 E7 oncoprotein impairs the function and morphology of DCs and induces the systemic accumulation of CD11b(+)Gr1(+) cells. PMID:27478837

  3. The HPV16 E7 Oncoprotein Disrupts Dendritic Cell Function and Induces the Systemic Expansion of CD11b+Gr1+ Cells in a Transgenic Mouse Model

    PubMed Central

    Damian-Morales, Gabriela; Serafín-Higuera, Nicolás; Moreno-Eutimio, Mario Adán; Cortés-Malagón, Enoc M.; Bonilla-Delgado, José; Rodríguez-Uribe, Genaro; Ocadiz-Delgado, Rodolfo; Lambert, Paul F.

    2016-01-01

    Objective. The aim of this study was to analyze the effects of the HPV16 E7 oncoprotein on dendritic cells (DCs) and CD11b+Gr1+ cells using the K14E7 transgenic mouse model. Materials and Methods. The morphology of DCs was analyzed in male mouse skin on epidermal sheets using immunofluorescence and confocal microscopy. Flow cytometry was used to determine the percentages of DCs and CD11b+Gr1+ cells in different tissues and to evaluate the migration of DCs. Results. In the K14E7 mouse model, the morphology of Langerhans cells and the migratory activity of dendritic cells were abnormal. An increase in CD11b+Gr1+ cells was observed in the blood and skin of K14E7 mice, and molecules related to CD11b+Gr1+ chemoattraction (MCP1 and S100A9) were upregulated. Conclusions. These data suggest that the HPV16 E7 oncoprotein impairs the function and morphology of DCs and induces the systemic accumulation of CD11b+Gr1+ cells. PMID:27478837

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

    PubMed

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

    2006-01-01

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

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

    PubMed Central

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

    2013-01-01

    Our previous studies on cutaneous beta human papillomavirus 38 (HPV38) E6 and E7 oncoproteins highlighted a novel activity of IκB kinase beta (IKKβ) in the nucleus of human keratinocytes, where it phosphorylates and stabilizes ΔNp73α, an antagonist of p53/p73 functions. Here, we further characterize the role of the IKKβ nuclear form. We show that IKKβ nuclear translocation and ΔNp73α accumulation are mediated mainly by HPV38 E7 oncoprotein. Chromatin immunoprecipitation (ChIP)/Re-ChIP experiments showed that ΔNp73α and IKKβ 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 ΔNp73α strongly affected the recruitment of the inhibitory transcriptional complex to the PIG3 promoter, with consequent restoration of p53-regulated gene expression. Finally, the ΔNp73α/IKKβ/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

  6. Human papillomavirus type 16 E7 oncoprotein mediates CCNA1 promoter methylation

    PubMed Central

    Chalertpet, Kanwalat; Pakdeechaidan, Watcharapong; Patel, Vyomesh; Mutirangura, Apiwat; Yanatatsaneejit, Pattamawadee

    2015-01-01

    Human papillomavirus (HPV) oncoproteins drive distinctive promoter methylation patterns in cancer. However, the underlying mechanism remains to be elucidated. Cyclin A1 (CCNA1) promoter methylation is strongly associated with HPV-associated cancer. CCNA1 methylation is found in HPV-associated cervical cancers, as well as in head and neck squamous cell cancer. Numerous pieces of evidence suggest that E7 may drive CCNA1 methylation. First, the CCNA1 promoter is methylated in HPV-positive epithelial lesions after transformation. Second, the CCNA1 promoter is methylated at a high level when HPV is integrated into the human genome. Finally, E7 has been shown to interact with DNA methyltransferase 1 (Dnmt1). Here, we sought to determine the mechanism by which E7 increases methylation in cervical cancer by using CCNA1 as a gene model. We investigated whether E7 induces CCNA1 promoter methylation, resulting in the loss of expression. Using both E7 knockdown and overexpression approaches in SiHa and C33a cells, our data showed that CCNA1 promoter methylation decreases with a corresponding increase in expression in E7 siRNA-transfected cells. By contrast, CCNA1 promoter methylation was augmented with a corresponding reduction in expression in E7-overexpressing cells. To confirm whether the binding of the E7–Dnmt1 complex to the CCNA1 promoter induced methylation and loss of expression, ChIP assays were carried out in E7-, del CR3-E7 and vector control-overexpressing C33a cells. The data showed that E7 induced CCNA1 methylation by forming a complex with Dnmt1 at the CCNA1 promoter, resulting in the subsequent reduction of expression in cancers. It is interesting to further explore the genome-wide mechanism of E7 oncoprotein-mediated DNA methylation. PMID:26250467

  7. Human papillomavirus type 16 E7 oncoprotein upregulates the retinoic acid receptor-beta expression in cervical cancer cell lines and K14E7 transgenic mice.

    PubMed

    Gutiérrez, Jorge; García-Villa, Enrique; Ocadiz-Delgado, Rodolfo; Cortés-Malagón, Enoc M; Vázquez, Juan; Roman-Rosales, Alejandra; Alvarez-Rios, Elizabeth; Celik, Haydar; Romano, Marta C; Üren, Aykut; Lambert, Paul F; Gariglio, Patricio

    2015-10-01

    Persistent infection with high-risk human papillomaviruses is the main etiological factor in cervical cancer (CC). The human papillomavirus type 16 (HPV16) E7 oncoprotein alters several cellular processes, regulating the expression of many genes in order to avoid cell cycle control. Retinoic acid receptor beta (RARB) blocks cell growth, inducing differentiation and apoptosis. This tumor suppressor gene is gradually silenced in late passages of foreskin keratinocytes immortalized with HPV16 and in various tumors, including CC, mainly by epigenetic modifications. We investigated the effect of E7 oncoprotein on RARB gene expression. We found that HPV16 E7 increases RARB mRNA and RAR-beta protein expression both in vitro and in the cervix of young K14E7 transgenic mice. In E7-expressing cells, RARB overexpression is further increased in the presence of the tumor suppressor p53 (TP53) R273C mutant. This effect does not change when either C33-A or E7-expressing C33-A cell line is treated with Trichostatin A, suggesting that E7 enhances RARB expression independently of histone deacetylases inhibition. These findings indicate that RARB overexpression is part of the early molecular events induced by the E7 oncoprotein. PMID:26173416

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

    PubMed Central

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

    2007-01-01

    The E6 and E7 oncoproteins of the high-risk HPV type16 represent ideal targets for HPV vaccine development, they being consistently expressed in cervical cancer lesions. Since HPV-16 is primarily transmitted through genital mucosal route, mucosal immune responses constitute an essential feature for vaccination strategies against HPV-associated lesions. We present here evidence showing that mucosal immunization of mice by the intranasal route with a mixture of peptides E744–62 and E643–57 from the E7 and E6 oncoproteins of HPV-16, respectively, using a mutant cholera toxin adjuvant (CT-2*), primed strong antigen-specific cellular immune responses in systemic and mucosal tissues. Significant levels of IFN-γ production by both CD4 and CD8 cells were observed along with CTL responses that were effective against both peptide-pulsed targets as well as syngeneic tumor cells (TC-1) expressing the cognate E6 and E7 proteins. Furthermore, mice immunized with the peptide mixture and CT-2* effectively resisted TC-1 tumor challenge. These results together with our earlier observations that T cell responses to these peptides correlate with recurrence-free survival in women after ablative treatment for HPV-associated cervical intraepithelial neoplasia, support the potential of these E6 and E7 peptides for inclusion in vaccine formulations. PMID:17291642

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

    SciTech Connect

    Knapp, Alixandra A.; McManus, Patrick M.; Bockstall, Katy; Moroianu, Junona

    2009-01-05

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

  10. 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

    Zhou Xiaobo; Muenger, Karl

    2009-03-01

    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.

  11. Phylogenetic and functional analysis of sequence variation of human papillomavirus type 31 E6 and E7 oncoproteins.

    PubMed

    Ferenczi, Annamária; Gyöngyösi, Eszter; Szalmás, Anita; László, Brigitta; Kónya, József; Veress, György

    2016-09-01

    High-risk human papillomaviruses (HPV) are the causative agents of cervical and other anogenital cancers as well as a subset of head and neck cancers. The E6 and E7 oncoproteins of HPV contribute to oncogenesis by associating with the tumour suppressor protein p53 and pRb, respectively. For HPV types 16 and 18, intratypic sequence variation was shown to have biological and clinical significance. The functional significance of sequence variation among HPV 31 variants was studied less intensively. HPV 31 variants belonging to different variant lineages were found to have differences in persistence and in the ability to cause high grade cervical intraepithelial neoplasia. In the present study, we started to explore the functional effects of natural sequence variation of HPV 31 E6 and E7 oncoproteins. The E6 variants were tested for their effects on p53 protein stability and transcriptional activity, while the E7 variants were tested for their effects on pRb protein level and also on the transcriptional activity of E2F transcription factors. HPV 31 E7 variants displayed uniform effects on pRb stability and also on the activity of E2F transcription factors. HPV 31 E6 variants had remarkable differences in the ability to inhibit the trans-activation function of p53 but not in the ability to induce the in vivo degradation of p53. Our results indicate that natural sequence variation of the HPV 31 E6 protein may be involved in the observed differences in the oncogenic potential between HPV 31 variants. PMID:27197052

  12. Indoleamine 2,3-dioxygenase Activity Contributes to Local Immune Suppression in the Skin Expressing Human Papillomavirus Oncoprotein E7

    PubMed Central

    Mittal, D; Kassianos, AJ; Tran, LS; Bergot, AS; Gosmann, C; Hofmann, J; Blumenthal, A; Leggatt, GR; Frazer, IH

    2013-01-01

    Chronic infection of anogenital epithelium with human papillomavirus (HPV) promotes development of cancer. Many pathogens evoke immunosuppressive mechanisms to enable persistent infection. We have previously shown that grafted skin expressing HPV16 E7 oncoprotein from a keratin-14 promoter (K14E7) is not rejected by a syngeneic, immunocompetent host. In this study we show that indoleamine 2, 3-dioxygenase (IDO) 1, an IFN-γ inducible immunoregulatory molecule, is more highly expressed by langerin−ve dermal dendritic cells from K14E7 skin than nontransgenic control skin. Furthermore, inhibiting IDO activity using 1-D/L-methyl tryptophan promotes K14E7 skin graft rejection. Increased IDO1 expression and activity in K14E7 skin requires IFN-γ and iNKT cells, both of which have been shown to negatively regulate T-cell effector function and suppress K14E7 graft rejection. Further, dendritic cells from K14E7 skin express higher level of IFN-γ receptor (IFN-γR) than dendritic cells from control skin. K14E7 transgenic skin recruits significantly higher number of dendritic cells, independent of IFN-γ and IFN-γR expression. Consistent with these observations in a murine model, we found higher expression of IDO1 and IFN-γ but not IDO2 in the cervical epithelium of patients with HPV-associated cervical intraepithelial neoplasia (CIN) 2/3. Our data support a hypothesis that induction of IDO1 in HPV infected skin contributes to evasion of host immunity. PMID:23652797

  13. Bovine papillomavirus E5 and E7 oncoproteins in naturally occurring tumors: are two better than one?

    PubMed

    Corteggio, Annunziata; Altamura, Gennaro; Roperto, Franco; Borzacchiello, Giuseppe

    2013-01-01

    Bovine papillomaviruses (BPVs) are oncogenic DNA viruses, which mainly induce benign lesions of cutaneous and/or mucosal epithelia in cattle. Thirteen (BPV 1-13) different viral genotypes have been characterized so far. BPVs are usually species-specific but BPV 1/2 may also infect equids as well as buffaloes and bison and cause tumors in these species. BPV-induced benign lesions usually regress, however occasionally they develop into cancer particularly in the presence of environmental carcinogenic co-factors. The major transforming protein of BPV is E5, a very short hydrophobic, transmembrane protein with many oncogenic activities. E5 contributes to cell transformation through the activation of the cellular β receptor for the platelet-derived growth factor (PDGFβ-r), it also decreases cell surface expression of major histocompatibility complex class I (MHCI) causing viral escape from immunosurveillance, and plays a role in the inhibition of the intracellular communication by means of aberrant connexin expression. E7 is considered as a weak transforming gene, it synergies with E5 in cell transformation during cancer development. E7 expression correlates in vivo with the over-expression of β1-integrin, which plays a role in the regulation of keratinocytes proliferation and differentiation. Additionally, E7 is involved in cell-mediated immune responses leading to tumour rejection, in anoikis process by direct binding to p600, and in invasion process by upregulation of Matrix metalloproteinase1 (MMP-1) expression. Studies on the role of BPV E5 and E7 oncoproteins in naturally occurring tumours are of scientific value, as they may shed new light on the biological role of these two oncogenes in cell transformation. PMID:23302179

  14. Regulation of the Wnt/β-Catenin Signaling Pathway by Human Papillomavirus E6 and E7 Oncoproteins

    PubMed Central

    Muñoz Bello, Jesus Omar; Olmedo Nieva, Leslie; Contreras Paredes, Adriana; Fuentes Gonzalez, Alma Mariana; Rocha Zavaleta, Leticia; Lizano, Marcela

    2015-01-01

    Cell signaling pathways are the mechanisms by which cells transduce external stimuli, which control the transcription of genes, to regulate diverse biological effects. In cancer, distinct signaling pathways, such as the Wnt/β-catenin pathway, have been implicated in the deregulation of critical molecular processes that affect cell proliferation and differentiation. For example, changes in β-catenin localization have been identified in Human Papillomavirus (HPV)-related cancers as the lesion progresses. Specifically, β-catenin relocates from the membrane/cytoplasm to the nucleus, suggesting that this transcription regulator participates in cervical carcinogenesis. The E6 and E7 oncoproteins are responsible for the transforming activity of HPV, and some studies have implicated these viral oncoproteins in the regulation of the Wnt/β-catenin pathway. Nevertheless, new interactions of HPV oncoproteins with cellular proteins are emerging, and the study of the biological effects of such interactions will help to understand HPV-related carcinogenesis. This review addresses the accumulated evidence of the involvement of the HPV E6 and E7 oncoproteins in the activation of the Wnt/β-catenin pathway. PMID:26295406

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

    PubMed Central

    Yu, Yueyang; Munger, Karl

    2012-01-01

    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

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

    SciTech Connect

    Yu, Yueyang; Munger, Karl

    2012-10-10

    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.

  17. Human Papillomavirus Type 16 E7 Oncoprotein Causes a Delay in Repair of DNA Damage

    PubMed Central

    Park, Jung Wook; Nickel, Kwangok P.; Torres, Alexandra D.; Lee, Denis; Lambert, Paul F.; Kimple, Randall J.

    2014-01-01

    Background and Purpose Patients with Human papillomavirus related (HPV+) head and neck cancers (HNCs) demonstrate improved clinical outcomes compared to traditional HPV negative (HPV−) HNC patients. We have recently shown that HPV+ HNC cells are more sensitive to radiation than HPV− HNC cells. However, roles of HPV oncogenes in regulating the response of DNA damage repair remain unknown. Material and Methods Using immortalized normal oral epithelial cell lines, HPV+ HNC derived cell lines, and HPV16 E7-transgenic mice we assessed the repair of DNA damage using γ-H2AX foci, single and split dose clonogenic survival assays, and immunoblot. The ability of E7 to modulate expression of proteins associated with DNA repair pathways was assessed by immunoblot. Results HPV16 E7 increased retention of γ-H2AX nuclear foci and significantly decreased sublethal DNA damage repair. While phospho-ATM, phospho-ATR, Ku70, and Ku80 expressions were not altered by E7, Rad51 was induced by E7. Correspondingly, HPV+ HNC cell lines showed retention of Rad51 after γ-radiation. Conclusions Our findings provide further understanding as to how HPV16 E7 manipulates cellular DNA damage responses that may underlie its oncogenic potential and influence the altered sensitivity to radiation seen in HPV+ HNC as compared to HPV− HNC. PMID:25216575

  18. Chemical synthesis of human papillomavirus type 16 E7 oncoprotein: autonomous protein domains for induction of cellular DNA synthesis and for trans activation.

    PubMed

    Rawls, J A; Pusztai, R; Green, M

    1990-12-01

    The human papillomavirus type 16 E7 protein belongs to a family of nuclear oncoproteins that share amino acid sequences and functional homology. To localize biochemical activities associated with E7, we chemically synthesized the full-length 98-amino-acid polypeptide and several deletion mutant peptides. We show that the E7 polypeptide is biologically active and possesses at least two functional domains; the first induces cellular DNA synthesis in quiescent rodent cells, and the second trans activates the adenovirus E1A-inducible early E2 promoter and binds zinc. Further, each domain is autonomous and can function on separate peptides. DNA synthesis induction activity maps within the N-terminal portion of the molecule, which contains sequences related to adenovirus E1A conserved domains 1 and 2 required for cell transformation and binding of the retinoblastoma gene product. trans-Activation and Zn-binding activities map within the C-terminal portion of the molecule, a region which contains Cys-X-X-Cys motifs. trans Activation does not require protein synthesis, implying a mechanism that involves interaction with a preexisting cellular factor(s). E7 trans activates the adenovirus E2 promoter but not other E1A-inducible viral promoters, suggesting the possibility that E7 trans activation involves interaction, directly or indirectly, with cellular transcription factor E2F. PMID:2173783

  19. Naive and radiolabeled antibodies to E6 and E7 HPV-16 oncoproteins show pronounced antitumor activity in experimental cervical cancer

    PubMed Central

    Phaëton, R; Gutierrez, J; Jiang, Z; Karabakhtsian, RG; Albanese, J; Sunkara, J; Fisher, DR; Goldberg, GL; Dadachova, E

    2015-01-01

    Background In spite of profound reduction in incidence, cervical cancer claims >275,000 lives annually. Previously we demonstrated efficacy and safety of radioimmunotherapy directed at HPV16 E6 oncoprotein in experimental cervical cancer. Materials & methods We undertook a direct comparison of targeting E7 and E6 oncoproteins with specific 188Rhenium-labeled monoclonal antibodies in CasKi subcutaneous xenografts of cervical cancer cells in mice. Results The most significant tumor inhibition was seen in radioimmunotherapy-treated mice, followed by the unlabeled monoclonal antibodies to E6 and E7. No hematological toxicity was observed. Immunohistochemistry suggests that the effect of unlabeled antibodies is C3 complement mediated. Conclusion We have demonstrated for the first time that radioimmunotherapy directed toward E7 oncoprotein inhibits experimental tumors growth, decreases E7 expression and may offer a novel approach to cervical cancer therapy. PMID:26098137

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

    PubMed

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

    2011-11-01

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

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

    PubMed Central

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

    2008-01-01

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

  2. Nuclear export of cutaneous HPV8 E7 oncoprotein is mediated by a leucine-rich nuclear export signal via a CRM1 pathway

    SciTech Connect

    Onder, Zeynep; Chang, Vivian; Moroianu, Junona

    2015-01-01

    We recently determined that the nuclear import of cutaneous beta genus HPV8 E7 oncoprotein it is mediated by its zinc-binding domain via direct hydrophobic interactions with the FG nucleoporins Nup62 and Nup153 (Onder and Moroianu, 2014). Here we investigated the nuclear export of HPV8 E7 oncoprotein using confocal microscopy after transfections of HeLa cells with EGFP–8cE7 and mutant plasmids and treatment with Ratjadone A nuclear export inhibitor. We determined that HPV8 E7 contains a leucine-rich nuclear export signal (NES), {sub 76}IRTFQELLF{sub 84}, within its zinc-binding domain that mediates its nuclear export via a CRM1 pathway. We found that HPV8 E7 interacts with CRM1 and that the hydrophobic amino acid residues I76, F79 and L82 of the NES are essential for this interaction and for nuclear export of HPV8 E7 oncoprotein. - Highlights: • HPV8 E7 has a leucine-rich NES within its zinc-binding domain that mediates its nuclear export. • CRM1 nuclear export receptor interacts with HPV8 E7 and mediates its export. • Identification of the critical hydrophobic amino acids of the NES of HPV8 E7.

  3. The expression of miR-21 and miR-143 is deregulated by the HPV16 E7 oncoprotein and 17β-estradiol.

    PubMed

    Gómez-Gómez, Yazmín; Organista-Nava, Jorge; Ocadiz-Delgado, Rodolfo; García-Villa, Enrique; Leyva-Vazquez, Marco Antonio; Illades-Aguiar, Berenice; Lambert, Paul F; García-Carrancá, Alejandro; Gariglio, Patricio

    2016-08-01

    MicroRNAs (miRNAs) are a class of non-coding RNAs that negatively regulate their target mRNAs at a posttranscriptional level, thereby affecting crucial processes in cancer development. However, little is known about the molecular events that control expression of miRNAs in cervical cancer (CC). HPV16 E7 oncoprotein in conjunction with estrogen are sufficient to produce high grade cervical dysplasia and invasive cervical malignancies in a mouse model. In the present study, we determined the potential role that the E7 oncoprotein and 17β-estradiol (E2) play in the deregulation of miR-21 and miR-143 expression levels by these two risk factors. We found that, while the expression of miR-21 was upregulated and the expression of miR-143 was downregulated by the HPV16 E7 oncoprotein in vivo, and in vitro and that E2 treatment is also implicated in the deregulation of these important miRNAs in vivo. Sustained upregulation of miR-21 resulted in suppression of PTEN expression, and repression of miR-143 increased the mRNA and protein levels from Bcl-2. These results suggested that HPV type 16 E7 oncoprotein and E2 play an important role in regulating miR-21 and miR-143 expression. We have observed similar results in CC patients containing HPV16 sequences, suggesting that these miRNAs could serve as diagnostic biomarkers in CC. The present study highlights the roles of miRNAs in cervical tissue and implicates these important molecules in cervical carcinogenesis. PMID:27278606

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

    SciTech Connect

    Onder, Zeynep; Moroianu, Junona

    2014-01-20

    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 {sub 65}LRLFV{sub 69} 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 {sub 65}LRLFV{sub 69} 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. - Highlights: • HPV8 E7 has a cNLS within its zinc-binding domain that mediates its nuclear import. • Discovery of a hydrophobic patch that is critical for the nuclear import of HPV8 E7. • HPV8 E7 nuclear import is mediated by hydrophobic interactions with FG-Nups, Nup62 and Nup153.

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

    PubMed Central

    Yu, Yueyang; Munger, Karl

    2013-01-01

    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

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

    PubMed Central

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

    2014-01-01

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

  7. Transcriptional regulation of E-cadherin and oncoprotein E7 by valproic acid in HPV positive cell lines

    PubMed Central

    Faghihloo, Ebrahim; Akbari, Abolfazl; Adjaminezhad-Fard, Fatemeh; Mokhtari-Azad, Talat

    2016-01-01

    Objective(s): Valproic acid (VPA) has proven to be as one of the most promising useful drug with anticancer properties. In this study, we investigate the VPA effects on E-cadherin expression in HeLa, TC1, MKN45, and HCT116 cell lines. This study assesses the effects of VPA on human papillomavirus E7 expression in HPV positive cell lines. Materials and Methods: Cell lines were treated by 2 mmol/l VPA and expression of E-cadherin and E7 was analyzed by quantitative real-time PCR. Student’s t test and ANOVA were used to determine changes in expression levels. Results: The results revealed that mean of E-cadherin expression is increased by VPA 1.8 times in HCT116 and MKN45 cell lines, also the mean of E-cadherin mRNA levels is up-regulated 2.9 times in HeLa and TC1 cell lines. So, E-cadherin augmentation induced by VPA in HeLa and TC-1, HPV positive cell lines, is higher than HPV negative cell lines MKN45 and HCT116. The mean of HPV E7 expression is decreased by VPA, 4.6 times in in HeLa and TC-1 cell lines. Conclusion: This study demonstrates that re-expression of E-cadherin by VPA in HPV positive cell lines is more than HPV negative cell lines. Whereas, HPV E7 reduces the expression of E-cadherin, reduction of HPV E7 expression by VPA is related to more augmentation of E-cadherin in HPV positive cell lines. So, this study demonstrates that VPA has more anticancer properties in HPV positive cell lines, and could potentially be a promising candidate for cervical cancer treatment. PMID:27482340

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

    PubMed Central

    Ajiro, Masahiko

    2015-01-01

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

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

    SciTech Connect

    Zhang Weifang; Li Jing; Kanginakudru, Sriramana; Zhao Weiming; Yu Xiuping; Chen, Jason J.

    2010-02-05

    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.

  10. High Risk HPV E6/E7 Oncoprotein Expression in Women with High Grade Squamous Intraepithelial Lesion.

    PubMed

    Valença, Jefferson Elias Cordeiro; Gonçalves, Ana Katherine; Guerreiro da Silva, Ismael Dale Cotrim; Eleutério Junior, José; Tenório da Silva, Terezinha; Bruneska, Danyelly; Ximenes, Ricardo Arraes de Alencar

    2016-03-01

    Purpose To correlate the expression of high-risk HPV E6 mRNA with pap smear, colposcopy, and biopsy results in women with high grade squamous intraepithelial lesion (HSIL). Methods A cross-sectional study was performed on women referred for primary care services after cytological diagnosis of HSIL. We evaluated the expression of E6/E7 mRNA of HPV types 16,18,31,33, and 45 and correlated the results with those of Pap smear, colposcopy, and biopsy. For amplification/detection of mRNA E6 / E7 we used NucliSENSEasyQ kit to detect HPV mRNA by polymerase chain reaction with primers/probes for HPV types 16, 18, 31, 33, and 45. Results Out of 128 valid tests, the results of 30 (23.4%) tests were negative and 98 (70%) tests were positive. Only one type of HPV was detected in 87.7% of the E6/E7 mRNA positive cases. HPV16 was detected in 61.2% of the cases, followed by HPV33 (26.5%), HPV31 (17.3%), HPV18 (10%), and HPV45 (4.08%). Pap smear tests revealed that the E6/E7 test was positive in 107 (83.8%) women with atypical squamous cells - high grade (ASC-H), HSIL, or higher. The E6/E7 test was positive in 69 (57.5%) specimens presenting negative cytology results. When analyzing the association with colposcopy results, the frequency of positive E6/E7 results increased with the severity of the injury, ranging from 57.1% in women without colposcopy-detected injury to 86.5% in those with higher levels of colposcopy findings. Of the 111 women who underwent biopsy and E6/E7 testing, the E6/E7 test was positive in 84.7% of the women who presented with lesions of cervical intraepithelial neoplasia (CIN) grade 2 or higher. Finally, 41.2% of women with a negative biopsy presented a positive E6/E7 test. Conclusions E6/E7 mRNA expression was higher in women with HSIL and CIN grade 2 or higher. PMID:27022787

  11. An RNA Aptamer Provides a Novel Approach for the Induction of Apoptosis by Targeting the HPV16 E7 Oncoprotein

    PubMed Central

    Nicol, Clare; Cesur, Özlem; Forrest, Sophie; Belyaeva, Tamara A.; Bunka, David H. J.; Blair, G. Eric; Stonehouse, Nicola J.

    2013-01-01

    Background Human papillomavirus 16 (HPV16) is a high-risk DNA tumour virus, which is a major causative agent of cervical cancer. Cellular transformation is associated with deregulated expression of the E6 and E7 oncogenes. E7 has been shown to bind a number of cellular proteins, including the cell cycle control protein pRb. In this study, RNA aptamers (small, single-stranded oligonucleotides selected for high-affinity binding) to HPV16 E7 were employed as molecular tools to further investigate these protein-protein interactions. Methodology/Principal Findings This study is focused on one aptamer (termed A2). Transfection of this molecule into HPV16-transformed cells resulted in inhibition of cell proliferation (shown using real-time cell electronic sensing and MTT assays) due to the induction of apoptosis (as demonstrated by Annexin V/propidium iodide staining). GST-pull down and bead binding assays were used to demonstrate that the binding of A2 required N-terminal residues of E7 known to be involved in interaction with the cell cycle control protein, pRb. Using a similar approach, A2 was shown to disrupt the interaction between E7 and pRb in vitro. Furthermore, transfection of HPV16-transformed cells with A2 appeared to result in the loss of E7 and rise in pRb levels, as observed by immunoblotting. Conclusions/Significance This paper includes the first characterisation of the effects of an E7 RNA aptamer in a cell line derived from a cervical carcinoma. Transfection of cells with A2 was correlated with the loss of E7 and the induction of apoptosis. Aptamers specific for a number of cellular and viral proteins have been documented previously; one aptamer (Macugen) is approved for clinical use and several others are in clinical trials. In addition to its role as a molecular tool, A2 could have further applications in the future. PMID:23738000

  12. Degradation of the Retinoblastoma Tumor Suppressor by the Human Papillomavirus Type 16 E7 Oncoprotein Is Important for Functional Inactivation and Is Separable from Proteasomal Degradation of E7

    PubMed Central

    Gonzalez, Sonia L.; Stremlau, Matt; He, Xi; Basile, John R.; Münger, Karl

    2001-01-01

    The steady-state level and metabolic half-life of retinoblastoma tumor suppressor protein pRB are decreased in cells that express high-risk human papillomavirus (HPV) E7 proteins. Here we show that pRB degradation is a direct activity of E7 and does not reflect a property of cell lines acquired during the selection process for E7 expression. An amino-terminal domain of E7 that does not directly contribute to pRB binding but is required for transformation is also necessary for E7-mediated pRB degradation. Treatment with inhibitors of the 26S proteasome not only blocks E7-mediated pRB degradation but also causes the stabilization of E7. Mutagenic analyses, however, reveal that the processes of proteasomal degradation of E7 and pRB are not linked processes. HPV type 16 E7 also targets the pRB-related proteins p107 and p130 for destabilization by a proteasome-dependent mechanism. Using the SAOS2 flat-cell assay as a biological indicator for pRB function, we demonstrate that pRB degradation, not solely binding, is important for the E7-induced inactivation of pRB. PMID:11462030

  13. The human papillomavirus (HPV) E7 protein antagonises an Imiquimod-induced inflammatory pathway in primary human keratinocytes.

    PubMed

    Richards, Kathryn H; Wasson, Christopher W; Watherston, Oliver; Doble, Rosella; Blair, G Eric; Wittmann, Miriam; Macdonald, Andrew

    2015-01-01

    High-risk human papillomaviruses (HPV) are the etiological pathogen of cervical and a number of ano-genital cancers. How HPVs overcome the significant barriers of the skin immune system has been the topic of intensive research. The E6 and E7 oncoproteins have emerged as key players in the deregulation of host innate immune pathways that are required for the recruitment of effector cells of the immune response. Here we demonstrate that E7, and to a lesser extend E6, strongly reduce NFκB activation in response to the inflammatory mediator imiquimod. Moreover, we establish that undifferentiated keratinocytes do not express the putative receptor for imiquimod, TLR7, and as such are stimulated by imiquimod through a novel pathway. Inhibition of imiquimod induced cytokine production required residues in the CR1 and CR3 regions of E7 and resulted in reduced nuclear translocation and acetylation of the p65 sub-unit of NFκB. The results provide further evidence for a TLR7-independent role of imiquimod in the epithelial immune response and reinforce the ability of the HPV oncoproteins to disrupt the innate immune response, which may have important consequences for establishment of a chronic infection. PMID:26268216

  14. 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

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

    2005-01-01

    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

  15. Inducing Oncoprotein Degradation to Improve Targeted Cancer Therapy1

    PubMed Central

    Ray, Dipankar; Cuneo, Kyle C.; Rehemtulla, Alnawaz; Lawrence, Theodore S.; Nyati, Mukesh K.

    2015-01-01

    Over the past decade, inhibition of the kinase activities of oncogenic proteins using small molecules and antibodies has been a mainstay of our anticancer drug development effort, resulting in several Food and Drug Administration–approved cancer therapies. The clinical effectiveness of kinase-targeted agents has been inconsistent, mostly because of the development of resistance. The expression and function of oncoproteins and tumor suppressors are regulated by numerous posttranslational protein modifications including phosphorylation, ubiquitination, and acetylation; hence, targeting specific posttranslational protein modifications provides for an attractive strategy for anticancer drug development. The present review discusses the hypothesis that targeted degradation of an oncoprotein may overcome many of the shortcomings seen with kinase inhibitors and that the approach would enable targeted inhibition of oncogenic proteins previously thought to be undruggable. PMID:26476077

  16. HUMAN PAPILLOMAVIRUS E7 ENHANCES HYPOXIA-INDUCIBLE FACTOR 1 MEDIATED TRANSCRIPTION BY INHIBITING BINDING OF HISTONE DEACETYLASES

    PubMed Central

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

    2010-01-01

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

  17. Attenuation of serum inducibility of immediate early genes by oncoproteins in tyrosine kinase signaling pathways.

    PubMed Central

    Yu, C L; Prochownik, E V; Imperiale, M J; Jove, R

    1993-01-01

    Immediate early genes involved in controlling cell proliferation are rapidly and transiently induced following stimulation of susceptible cells with serum. To study how oncoproteins regulate immediate early genes, we examined serum inducibility of these genes in cells transformed by various oncoproteins. We found that induction of the immediate early gene, c-fos, by serum stimulation was markedly attenuated in four independent cell lines stably transformed by the v-Src tyrosine kinase. Cells chronically transformed by other oncoproteins implicated in tyrosine kinase signaling pathways, including v-Sis, v-Ras, and v-Raf, showed the same pattern of attenuation. In contrast, serum inducibility of c-fos was not attenuated in cells transformed by simian virus 40, which is thought to transform cells through a different pathway. Cell cycle analyses showed that proliferation of these transformed cell lines could be arrested effectively in 0.1% serum, demonstrating that the attenuation was not simply due to continuous cycling of transformed cells after serum deprivation. Moreover, serum inducibility of other immediate early genes, including c-jun, junB, egr-1, and NGFI-B, also was strikingly attenuated by these same oncoproteins. Nuclear run-on transcription assays established that this attenuation of serum inducibility occurred at the transcriptional level. Finally, flow cytometric analysis demonstrated that serum-starved v-Src-transformed cells were viable and able to progress into S phase of the cell cycle after serum stimulation, even though the induction of immediate early genes was greatly attenuated in these cells. Our results suggest that activation of immediate early genes is repressed by chronic stimulation of tyrosine kinase signaling pathways in transformed cells. Images PMID:8384301

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

    SciTech Connect

    Eberhard, Jeremy; Onder, Zeynep; Moroianu, Junona

    2013-11-15

    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, {sub 65}LRLCV{sub 69}, 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. - Highlights: • An intact zinc-binding domain is essential for the nuclear localization of HPV16 E7. • Identification of a hydrophobic patch that is critical for the nuclear import of HPV16 E7. • HPV16 E7 interacts via its zinc-binding domain with the FG domain of Nup62.

  19. Efficacy of DNA vaccines forming e7 recombinant retroviral virus-like particles for the treatment of human papillomavirus-induced cancers.

    PubMed

    Lescaille, Geraldine; Pitoiset, Fabien; Macedo, Rodney; Baillou, Claude; Huret, Christophe; Klatzmann, David; Tartour, Eric; Lemoine, François M; Bellier, Bertrand

    2013-05-01

    Human papillomavirus (HPV) is involved in the development of anogenital tumors and also in the development of oropharyngeal head and neck carcinomas, where HPV-16, expressing the E6 and E7 oncoproteins, is the most frequent serotype. Although vaccines encoding L1 and L2 capsid HPV proteins are efficient for the prevention of HPV infection, they are inadequate for treating established tumors. Hence, development of innovative vaccine therapies targeting E6/E7 is important for controlling HPV-induced cancers. We have engineered a nononcogenic mutated E7-specific plasmo-retroVLP vaccine (pVLP-E7), consisting of plasmid DNA, that is able to form recombinant retrovirus-based virus-like particles (VLPs) that display E7 antigen into murine leukemia virus Gag proteins pseudotyped with vesicular stomatitis virus envelope glycoprotein (VSV-G). pVLP-E7 vaccinations were studied for their ability to generate specific immune responses and for induction of protective immunity against tumor cell challenge in preventive and therapeutic models. The produced VLPs induce the maturation of human dendritic cells in vitro and mount specific E7 T cell responses. Intradermic vaccinations of mice with pVLP-E7 show their efficacy to generate antigen-specific T cell responses, to prevent and protect animals from early TC-1 tumor development compared with standard DNA or VLP immunizations. The vaccine efficacy was also evaluated for advanced tumors in mice vaccinated at various time after the injection of TC-1 cells. Data show that pVLP-E7 vaccination can cure mice with already established tumors only when combined with Toll-like receptor-7 (TLR7) and TLR9 agonists. Our findings provide evidence that pVLPs, combining the advantages of DNA and VLP vaccines, appear to be a promising strategy for the treatment of HPV-induced cancers. PMID:23521528

  20. Epithelium Expressing the E7 Oncoprotein of HPV16 Attracts Immune-Modulatory Dendritic Cells to the Skin and Suppresses Their Antigen-Processing Capacity

    PubMed Central

    Chandra, Janin; Miao, Yan; Romoff, Natasha; Frazer, Ian H.

    2016-01-01

    Antigen presenting cells (APCs) in skin can promote either antigen-specific effector functions or antigen tolerance, and thus determine clearance or persistence of cutaneous viral infections. Human papillomavirus (HPV) infections can persist in squamous epithelium in immunocompetent individuals, and some persisting HPV infections, particularly with HPV16, promote malignant epithelial transformation. Here, we investigate whether local expression of the HPV16 protein most associated with malignant transformation, HPV16-E7, affects the phenotype and function of APC subsets in the skin. We demonstrate an expanded population of Langerhans cells in HPV16-E7 transgenic skin with distinct cell surface markers which express immune-modulatory enzymes and cytokines not expressed by cells from non transgenic skin. Furthermore, HPV16-E7 transgene expression in keratinocytes attracts new APC subsets to the epidermis. In vivo migration and transport of antigen to the draining lymph node by these APCs is markedly enhanced in HPV16-E7 expressing skin, whereas antigen-processing, as measured by proteolytic cleavage of DQ-OVA and activation of T cells in vivo by APCs, is significantly impaired. These data suggest that local expression of HPV16-E7 in keratinocytes can contribute to persisting infection with this oncogenic virus, by altering the phenotype and function of local APCs. PMID:27031095

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

    PubMed

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

    2015-02-01

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

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

    SciTech Connect

    Wang, Yisong

    2005-10-01

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

  3. A role of the kinase mTOR in cellular transformation induced by the oncoproteins P3k and Akt

    PubMed Central

    Aoki, Masahiro; Blazek, Erik; Vogt, Peter K.

    2001-01-01

    The oncoproteins P3k (homolog of the catalytic subunit of class IA phosphoinositide 3-kinase) and Akt (protein kinase B) induce oncogenic transformation of chicken embryo fibroblasts. The transformed cells show constitutive phosphorylation of the positive regulator of translation p70S6 kinase (S6K) and of the eukaryotic initiation factor 4E-BP1 binding protein (4E-BP1), a negative regulator of translation. Phosphorylation activates S6K and inactivates 4E-BP1. A mutant of Akt that retains kinase activity but does not induce phosphorylation of S6K or of 4E-BP1 fails to transform chicken embryo fibroblasts, suggesting a correlation between the oncogenicity of Akt and phosphorylation of S6K and 4E-BP1. The macrolide antibiotic rapamycin effectively blocks oncogenic transformation induced by either P3k or Akt but does not reduce the transforming activity of 11 other oncoproteins. Rapamycin inhibits the kinase mTOR, an important regulator of translation, and this inhibition requires binding of the antibiotic to the immunophilin FKBP12. Displacement of rapamycin from FKBP12 relieves the inhibition of mTOR and also restores P3k-induced transformation. These data are in accord with the hypothesis that transformation by P3k or Akt involves intervention in translational controls. PMID:11134523

  4. Increased sensitivity of HPV-positive head and neck cancer cell lines to x-irradiation ± Cisplatin due to decreased expression of E6 and E7 oncoproteins and enhanced apoptosis

    PubMed Central

    Ziemann, Frank; Arenz, Andrea; Preising, Stefanie; Wittekindt, Claus; Klussmann, Jens P; Engenhart-Cabillic, Rita; Wittig, Andrea

    2015-01-01

    Squamous cell carcinoma of the head and neck region (HNSCC), which is related to an infection with human papilloma virus (HPV), responds better to simultaneous radio-chemotherapy with Cisplatin based regimens than HPV-negative tumors. The underlying molecular mechanisms for this clinical observation are not fully understood. Therefore, the response of four HPV-positive (HPV+) (UM-SCC-47, UM-SCC-104, 93-VU-147T, UPCI:SCC152) and four HPV-negative (HPV-) (UD-SCC-1, UM-SCC-6, UM-SCC-11b, UT-SCC-33) HNSCC cell lines to x-irradiation ± Cisplatin incubation in terms of clonogenic survival, cell cycle progression, protein expression (cyclin A2, cyclin E2, E6, E7, p53) and induction of apoptosis, was investigated. HPV+ cells were more radio- and chemosensitive and were more effectively sensitized to x-irradiation by simultaneous Cisplatin incubation than HPV- cell lines. HPV+ cell lines revealed an increased and prolonged G2/M arrest after irradiation, whereas Cisplatin induced a blockage of cells in S phase. In comparison to irradiation only, addition of Cisplatin significantly enhanced apoptosis especially in HPV+ cell lines. While irradiation alone increased the amount of HPV E6 and E7 proteins, both were down-regulated by Cisplatin incubation either alone or in combination with x-rays, which however did not increase the expression of endogenous p53. Our results demonstrate that cell cycle deregulation together with downregulation of HPV E6 and E7 proteins facilitating apoptosis after Cisplatin incubation promote the enhanced sensitivity of HPV+ HNSCC cells to simultaneous radio-chemotherapy. Combined effects of irradiation and Cisplatin appear to be relevant in mediating the enhanced therapeutic response of HPV-related HNSCC and are indicative of the benefit of combined modality approaches in future treatment optimization strategies. PMID:26045983

  5. HPV16-E7 Expression in skin induces TSLP secretion, type 2 ILC infiltration and atopic dermatitis-like lesions

    PubMed Central

    Bergot, Anne-Sophie; Monnet, Nastasia; Tran, Le Son; Mittal, Deepak; Al-Kouba, Jane; Steptoe, Raymond J.; Grimbaldeston, Michele A.; Frazer, Ian H.; Wells, James W.

    2014-01-01

    Atopic dermatitis is a common pruritic and inflammatory skin disorder with unknown etiology. Most commonly occurring during early childhood, atopic dermatitis is associated with eczematous lesions and lichenification, in which the epidermis becomes hypertrophied resulting in thickening of the skin. In this study, we report an atopic dermatitis-like pathophysiology results in a murine model following the expression of the high-risk Human Papillomavirus (HPV) 16 oncoprotein E7 in keratinocytes under the Keratin 14 promoter. We show that HPV 16 E7 expression in the skin is associated with skin thickening, acanthosis and light spongiosis. Locally, HPV 16 E7 expressing skin secreted high levels of TSLP and contained increased numbers of ILCs. High levels of circulating IgE were associated with increased susceptibility to skin allergy in a model of cutaneous challenge, and to airway bronchiolar inflammation, enhanced airway goblet cell metaplasia and mucus production in a model of atopic march. Surprisingly, skin pathology occurred independently of T-cells and mast cells. Thus, our findings suggest that the expression of a single HPV oncogene in the skin can drive the onset of atopic dermatitis-like pathology through the induction of TSLP and type 2 ILC infiltration. PMID:25601274

  6. Inhibitory role of TRIP-Br1 oncoprotein in hypoxia-induced apoptosis in breast cancer cell lines.

    PubMed

    Li, Chengping; Jung, Samil; Yang, Young; Kim, Keun-Il; Lim, Jong-Seok; Cheon, Chung-Il; Lee, Myeong-Sok

    2016-06-01

    TRIP-Br1 oncoprotein is known to be involved in many vital cellular functions. In this study, we examined the role of TRIP-Br1 in hypoxia-induced cell death. Exposure to the overcrowded and CoCl2-induced hypoxic conditions increased TRIP-Br1 expression at the protein level in six breast cancer cell lines (MCF7, MDA-MB-231, T47D, Hs578D, BT549, and MDA-MB-435) but resulted in no significant change in three normal cell lines (MCF10A, MEF and NIH3T3). Our result revealed that CoCl2-induced hypoxia stimulated apoptosis and autophagy, in which TRIP-Br1 expression was found to be upregulated. Interestingly, TRIP-Br1 silencing in the MCF7 and MDA-MB-231 cancer cells accelerated apoptosis and destabilization of XIAP under the CoCl2-induced hypoxic condition, implying that TRIP-Br1 may render cancer cells resistant to apoptosis through the stabilization of XIAP. We also propose that TRIP-Br1 seems to be upregulated at least partly as a result of the inhibition of PI3K/AKT signaling pathway and the overexpression of HIF-1α. In conclusion, our findings suggest that TRIP-Br1 functions as an oncogenic protein by providing cancer cells resistance to the hypoxia-induced cell death. PMID:27035851

  7. Reprogrammed CRISPR-Cas9 targeting the conserved regions of HPV6/11 E7 genes inhibits proliferation and induces apoptosis in E7-transformed keratinocytes.

    PubMed

    Liu, Yu-Chen; Cai, Zhi-Ming; Zhang, Xue-Jun

    2016-01-01

    The persistence infection of low-risk type (type 6 or type 11) of human papillomavirus (HPV) is the main cause of genital warts. Given the high rate of recurrence after treatment, the use of a new molecular agent is certain to be of value. The aim of this study was to achieve targeted inactivation of viral E 7 gene in keratinocytes using the reprogrammed clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) 9 system. To accomplish this, a universal CRISPR-Cas9 system for targeting both HPV6/11 E 7 genes was constructed by using a dual guide RNA vector. After transfection of the vector into E 7-transfromed keratinocytes, the expression level of E 7 protein was measured using western-blot analysis and the sequence of the E 7 gene was determined using Sanger sequencing. Cell proliferation was analyzed by CCK-8 assay, and cell apoptosis was evaluated by Hoechst 33258 staining, flow cytometry analysis and ELISA assay. The results indicated that both HPV6/11 E 7 genes can be inactivated by the single CRISPR-Cas9 system. Furthermore, silencing of E 7 led to inhibition of cell proliferation and induction of apoptosis in E 7-transfromed keratinocytes but not in normal keratinocytes. Our data suggested that the reprogrammed CRISPR-Cas9 system has the potential for the development of an adjuvant therapy for genital warts. PMID:26228041

  8. The heat shock protein 90-binding geldanamycin inhibits cancer cell proliferation, down-regulates oncoproteins, and inhibits epidermal growth factor-induced invasion in thyroid cancer cell lines.

    PubMed

    Park, Jin-Woo; Yeh, Michael W; Wong, Mariwil G; Lobo, Margaret; Hyun, William C; Duh, Quan-Yang; Clark, Orlo H

    2003-07-01

    Heat shock protein 90 (HSP90) serves as a chaperone protein and plays a critical role in tumor cell growth and/or survival. Geldanamycin, a specific inhibitor of HSP90, is cytotoxic to several human cancer cell lines, but its effect in thyroid cancer is unknown. We, therefore, investigated the effect of geldanamycin on cell proliferation, oncoprotein expression, and invasion in human thyroid cancer cell lines. We used six thyroid cancer cell lines: TPC-1 (papillary), FTC-133, FTC-236, FTC-238 (follicular), XTC-1 (Hürthle cell), and ARO (anaplastic). We used the dimethyl-thiazol-diphenyltetrazolium bromide assay, a clonogenic assay, an apoptotic assay, and a Matrigel invasion assay. We evaluated oncoprotein expression using Western blots and flow cytometry. After 6 d of treatment with 50 nM geldanamycin, the percent inhibition of growth was 29.4% in TPC-1, 97.5% in FTC-133, 96.7% in FTC-236, 10.8% in FTC-238, 70.9% in XTC-1, and 45.5% in ARO cell lines. In the FTC-133 cell line, geldanamycin treatment decreased clonogenicity by 21% at a concentration of 50 nM; geldanamycin induced apoptosis and down-regulated c-Raf-1, mutant p53, and epidermal growth factor (EGF) receptor expression; geldanamycin inhibited EGF-stimulated invasion. In conclusion, geldanamycin inhibited cancer cell proliferation, down-regulated oncoproteins, and inhibited EGF-induced invasion in thyroid cancer cell lines. PMID:12843186

  9. Codon optimization of the human papillomavirus E7 oncogene induces a CD8+ T cell response to a cryptic epitope not harbored by wild-type E7.

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    1995-01-01

    In this study, we analysed immunocytochemically p53 expression in first primary and second primary cancers from 25 head and neck cancer patients (HNCPs) with multiple malignancies in comparison with oncoprotein expression in tumour tissues from 25 historical HNCP controls with single cancer in a match-paired analysis. Moreover, we investigated bleomycin-induced chromosome fragility in both groups of HNCPs and in 21 additional healthy controls. Thirty-nine out of 75 tumour specimens analysed (52%) showed positive p53 immunostaining. Eleven out of 25 (44%) from single cancer patients and 28 out of 50 (56%) tumours from HNCPs with multiple malignancies were p53 positive. In the group of multiple primary cancers, nine patients (36%) showed positive staining of both first and second primaries, whereas six (24%) had positive labelling of first primary cancer but not of the subsequent second primary, four (16%) patient showed p53 expression only in the second primary cancer and six (24%) patients showed no p53 immunoreactivity in both tumours. Chromosomal analysis demonstrated a higher sensitivity to clastogens of HNCPs with multiple tumours than of HNCPs with a single cancer (P < 0.01), and a significant correlation between chromosome fragility and p53 overexpression (P < 0.01) only in HNCPs with multiple malignancies more than in those with single head and neck cancer (P = 0.11). Moreover, we found that patients with p53-positive staining of both first and second primaries showed a statistically significant higher mutagen sensitivity than those with a single p53 immunoreactive tumour or those in whom both cancers were p53 negative (P < 0.01). Our data suggest that subjects with increased susceptibility to carcingogens after exposure to tobacco or alcohol are at higher risk for multiple cancers in which one of the most common genetic events is aberrant p53 expression. Images Figure 1 PMID:7734291

  11. Human Papillomavirus (HPV) E7 Induces Prolonged G2 following S Phase Reentry in Differentiated Human Keratinocytes*

    PubMed Central

    Banerjee, N. Sanjib; Wang, Hsu-Kun; Broker, Thomas R.; Chow, Louise T.

    2011-01-01

    The productive program of human papillomaviruses occurs in differentiated squamous keratinocytes. We have previously shown that HPV-18 DNA amplification initiates in spinous cells in organotypic cultures of primary human keratinocytes during prolonged G2 phase, as signified by abundant cytoplasmic cyclin B1 (Wang, H. K., Duffy, A. A., Broker, T. R., and Chow, L. T. (2009) Genes Dev. 23, 181–194). In this study, we demonstrated that the E7 protein, which induces S phase reentry in suprabasal cells by destabilizing the p130 pocket protein (Genovese, N. J., Banerjee, N. S., Broker, T. R., and Chow, L. T. (2008) J. Virol. 82, 4862–4873), also elicited extensive G2 responses. Western blots and indirect immunofluorescence assays were used to probe for host proteins known to control G2/M progression. E7 expression induced cytoplasmic accumulation of cyclin B1 and cdc2 in the suprabasal cells. The elevated cdc2 had inactivating phosphorylation on Thr14 or Tyr15, and possibly both, due to an increase in the responsible Wee1 and Myt1 kinases. In cells that harbored cytoplasmic cyclin B1 or cdc2, there was also an accumulation of the phosphatase-inactive cdc25C phosphorylated on Ser216, unable to activate cdc2. Moreover, E7 expression induced elevated expression of phosphorylated ATM (Ser1981) and the downstream phosphorylated Chk1, Chk2, and JNKs, kinases known to inactivate cdc25C. Similar results were observed in primary human keratinocyte raft cultures in which the productive program of HPV-18 took place. Collectively, this study has revealed the mechanisms by which E7 induces prolonged G2 phase in the differentiated cells following S phase induction. PMID:21321122

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

    PubMed

    Ito, Masaki; Machida, Yasunori

    2015-05-01

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

  13. Arsenic trioxide and all-trans retinoic acid target NPM1 mutant oncoprotein levels and induce apoptosis in NPM1-mutated AML cells.

    PubMed

    Martelli, Maria Paola; Gionfriddo, Ilaria; Mezzasoma, Federica; Milano, Francesca; Pierangeli, Sara; Mulas, Floriana; Pacini, Roberta; Tabarrini, Alessia; Pettirossi, Valentina; Rossi, Roberta; Vetro, Calogero; Brunetti, Lorenzo; Sportoletti, Paolo; Tiacci, Enrico; Di Raimondo, Francesco; Falini, Brunangelo

    2015-05-28

    Nucleophosmin (NPM1) mutations represent an attractive therapeutic target in acute myeloid leukemia (AML) because they are common (∼30% AML), stable, and behave as a founder genetic lesion. Oncoprotein targeting can be a successful strategy to treat AML, as proved in acute promyelocytic leukemia by treatment with all-trans retinoic acid (ATRA) plus arsenic trioxide (ATO), which degrade the promyelocytic leukemia (PML)-retinoic acid receptor fusion protein. Adjunct of ATRA to chemotherapy was reported to be beneficial for NPM1-mutated AML patients. Leukemic cells with NPM1 mutation also showed sensibility to ATO in vitro. Here, we explore the mechanisms underlying these observations and show that ATO/ATRA induce proteasome-dependent degradation of NPM1 leukemic protein and apoptosis in NPM1-mutated AML cell lines and primary patients' cells. We also show that PML intracellular distribution is altered in NPM1-mutated AML cells and reverted by arsenic through oxidative stress induction. Interestingly, similarly to what was described for PML, oxidative stress also mediates ATO-induced degradation of the NPM1 mutant oncoprotein. Strikingly, NPM1 mutant downregulation by ATO/ATRA was shown to potentiate response to the anthracyclin daunorubicin. These findings provide experimental evidence for further exploring ATO/ATRA in preclinical NPM1-mutated AML in vivo models and a rationale for exploiting these compounds in chemotherapeutic regimens in clinics. PMID:25795919

  14. E1B and E4 Oncoproteins of Adenovirus Antagonize the Effect of Apoptosis Inducing Factor

    PubMed Central

    Turner, Roberta L.; Wilkinson, John C.; Ornelles, David A.

    2014-01-01

    Adenovirus inundates the productively infected cell with linear, double-stranded DNA and an abundance of single-stranded DNA. The cellular response to this stimulus is antagonized by the adenoviral E1B and E4 early genes. A mutant group C adenovirus that fails to express the E1B-55K and E4orf3 genes is unable to suppress the DNA-damage response. Cells infected with this double-mutant virus display significant morphological heterogeneity at late times of infection and frequently contain fragmented nuclei. Nuclear fragmentation was due to the translocation of apoptosis inducing factor (AIF) from the mitochondria into the nucleus. The release of AIF was dependent on active poly(ADP-ribose) polymerase-1 (PARP-1), which appeared to be activated by viral DNA replication. Nuclear fragmentation did not occur in AIF-deficient cells or in cells treated with a PARP-1 inhibitor. The E1B-55K or E4orf3 proteins independently prevented nuclear fragmentation subsequent to PARP-1 activation, possibly by altering the intracellular distribution of PAR-modified proteins. PMID:24889240

  15. E1B and E4 oncoproteins of adenovirus antagonize the effect of apoptosis inducing factor

    SciTech Connect

    Turner, Roberta L.; Wilkinson, John C.; Ornelles, David A.

    2014-05-15

    Adenovirus inundates the productively infected cell with linear, double-stranded DNA and an abundance of single-stranded DNA. The cellular response to this stimulus is antagonized by the adenoviral E1B and E4 early genes. A mutant group C adenovirus that fails to express the E1B-55K and E4ORF3 genes is unable to suppress the DNA-damage response. Cells infected with this double-mutant virus display significant morphological heterogeneity at late times of infection and frequently contain fragmented nuclei. Nuclear fragmentation was due to the translocation of apoptosis inducing factor (AIF) from the mitochondria into the nucleus. The release of AIF was dependent on active poly(ADP-ribose) polymerase-1 (PARP-1), which appeared to be activated by viral DNA replication. Nuclear fragmentation did not occur in AIF-deficient cells or in cells treated with a PARP-1 inhibitor. The E1B-55K or E4ORF3 proteins independently prevented nuclear fragmentation subsequent to PARP-1 activation, possibly by altering the intracellular distribution of PAR-modified proteins. - Highlights: • E1B-55K or E4orf3 prevents nuclear fragmentation. • Nuclear fragmentation requires AIF and PARP-1 activity. • Adenovirus DNA replication activates PARP-1. • E1B-55K or E4orf3 proteins alter the distribution of PAR.

  16. Role of Cdc6 in re-replication in cells expressing human papillomavirus E7 oncogene.

    PubMed

    Fan, Xueli; Zhou, Yunying; Chen, Jason J

    2016-08-01

    The E7 oncoprotein of high-risk human papillomavirus (HPV) types induces DNA re-replication that contributes to carcinogenesis; however, the mechanism is not fully understood. To better understand the mechanism by which E7 induces re-replication, we investigated the expression and function of cell division cycle 6 (Cdc6) in E7-expressing cells. Cdc6 is a DNA replication initiation factor and exhibits oncogenic activities when overexpressed. We found that in E7-expressing cells, the steady-state level of Cdc6 protein was upregulated and its half-life was increased. Cdc6 was localized to the nucleus and associated with chromatin, especially upon DNA damage. Importantly, downregulation of Cdc6 reduced E7-induced re-replication. Interestingly, the level of Cdc6 phosphorylation at serine 54 (S54P) was increased in E7-expressing cells. S54P was associated with an increase in the total amount of Cdc6 and chromatin-bound Cdc6. DNA damage-enhanced upregulation and chromatin binding of Cdc6 appeared to be due to downregulation of cyclin-dependent kinase 1 (Cdk1) as Cdk1 knockdown increased Cdc6 levels. Furthermore, Cdk1 knockdown or inhibition led to re-replication. These findings shed light on the mechanism by which HPV induces genomic instability and may help identify potential targets for drug development. PMID:27207654

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

    SciTech Connect

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

    2014-01-05

    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. - Highlights: • miR-24 and miR-205 are induced during keratinocyte differentiation. • This induction is lost in keratinocytes expressing HPV onco-proteins E6 and E7. • miR-205 is dependent upon pRb expression. • miR-24 targets p27 in cycling keratinocytes.

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

    PubMed

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

    2007-01-11

    Aberrant centrosome numbers are detected in virtually all human cancers where they can contribute to chromosomal instability by promoting mitotic spindle abnormalities. Despite their widespread occurrence, the molecular mechanisms that underlie centrosome amplification are only beginning to emerge. Here, we present evidence for a novel regulatory circuit involved in centrosome overduplication that centers on RNA polymerase II (pol II). We found that human papillomavirus type 16 E7 (HPV-16 E7)- and hydroxyurea (HU)-induced centriole overduplication are abrogated by alpha-amanitin, a potent and specific RNA pol II inhibitor. In contrast, normal centriole duplication proceeded undisturbed in alpha-amanitin-treated cells. Centriole overduplication was significantly reduced by siRNA-mediated knock down of CREB-binding protein (CBP), a transcriptional co-activator. We identified cyclin A2 as a key transcriptional target of RNA pol II during HU-induced centriole overduplication. Collectively, our results show that ongoing RNA pol II transcription is required for centriole overduplication whereas it may be dispensable for normal centriole duplication. Given that many chemotherapeutic agents function through inhibition of transcription, our results may help to develop strategies to target centrosome-mediated chromosomal instability for cancer therapy and prevention. PMID:16819507

  19. Chronic morphine induces up-regulation of the pro-apoptotic Fas receptor and down-regulation of the anti-apoptotic Bcl-2 oncoprotein in rat brain

    PubMed Central

    Boronat, M Assumpció; García-Fuster, M Julia; García-Sevilla, Jesús A

    2001-01-01

    This study was designed to assess the influence of activation and blockade of the endogenous opioid system in the brain on two key proteins involved in the regulation of programmed cell death: the pro-apoptotic Fas receptor and the anti-apoptotic Bcl-2 oncoprotein. The acute treatment of rats with the μ-opioid receptor agonist morphine (3 – 30 mg kg−1, i.p., 2 h) did not modify the immunodensity of Fas or Bcl-2 proteins in the cerebral cortex. Similarly, the acute treatment with low and high doses of the antagonist naloxone (1 and 100 mg kg−1, i.p., 2 h) did not alter Fas or Bcl-2 protein expression in brain cortex. These results discounted a tonic regulation through opioid receptors on Fas and Bcl-2 proteins in rat brain. Chronic morphine (10 – 100 mg kg−1, 5 days, and 10 mg kg−1, 13 days) induced marked increases (47 – 123%) in the immunodensity of Fas receptor in the cerebral cortex. In contrast, chronic morphine (5 and 13 days) decreased the immunodensity of Bcl-2 protein (15 – 30%) in brain cortex. Chronic naloxone (10 mg kg−1, 13 days) did not alter the immunodensities of Fas and Bcl-2 proteins in the cerebral cortex. The concurrent chronic treatment (13 days) of naloxone (10 mg kg−1) and morphine (10 mg kg−1) completely prevented the morphine-induced increase in Fas receptor and decrease in Bcl-2 protein immunoreactivities in the cerebral cortex. The results indicate that morphine, through the sustained activation of opioid receptors, can promote abnormal programmed cell death by enhancing the expression of pro-apoptotic Fas receptor protein and damping the expression of anti-apoptotic Bcl-2 oncoprotein. PMID:11704646

  20. 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

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

    2007-02-01

    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

  1. Carboxyl-terminal fusion of E7 into Flagellin shifts TLR5 activation to NLRC4/NAIP5 activation and induces TLR5-independent anti-tumor immunity

    PubMed Central

    Lin, Kuo-Hsing; Chang, Li-Sheng; Tian, Chun-Yuan; Yeh, Yi-Chen; Chen, Yu-Jie; Chuang, Tsung-Hsien; Liu, Shih-Jen; Leng, Chih-Hsiang

    2016-01-01

    Flagellin has the capacity to activate both Toll-like receptor 5 (TLR5) and Nod-like receptor C4 (NLRC4)/neuronal apoptosis inhibitory protein 5 (NAIP5) inflammasome signaling. We fused E7m (the inactivated E7 of human papillomavirus) to either end of the flagellin protein, and the resulting recombinant flagellin-E7m proteins (rFliCE7m and rE7mFliC) were used as immunogens. Both fusion proteins activated receptor signaling to different degrees. rE7mFliC-induced TLR5 activity was 10-fold higher than that of rFliCE7m, whereas rFliCE7m activated the NLRC4/NAIP5 pathway more strongly. Therefore, these recombinant proteins provided a tool to investigate which signaling pathway is critical for the induction of antigen-specific T cell responses and anti-tumor immunity. We demonstrated that rFliCE7m induced higher levels of E7-specific IFN-gamma-secreting cells and cytotoxic T lymphocytes (CTLs) than rE7mFliC, and a single injection with rFliCE7m but not rE7mFliC inhibited E7-expressing tumor growth in vivo. Furthermore, we confirmed that CD8+ T cells played a major role in the anti-tumor immunity induced by rFliCE7m. These findings suggested that the NLRC4/NAIP5 intracellular signaling pathway was critical for the induction of anti-tumor immunity. These observations provide important information for the rational design of flagellin-based immunotherapy. PMID:27063435

  2. Design, Immune Responses and Anti-Tumor Potential of an HPV16 E6E7 Multi-Epitope Vaccine

    PubMed Central

    Chaves, Agatha A. Muniz; Cavalher, Aline Marques; Lopes, Aline Soriano; Diniz, Mariana de Oliveira; Schanoski, Alessandra Soares; de Melo, Robson Lopes; Ferreira, Luís Carlos de Souza; de Oliveira, Maria Leonor S.; Demasi, Marilene; Ho, Paulo Lee

    2015-01-01

    Cervical cancer is a common type of cancer among women worldwide and infection with high-risk human papillomavirus (HPVs) types represents the major risk factor for the etiopathogenesis of the disease. HPV-16 is the most frequently identified HPV type in cervical lesions and expression of E6 and E7 oncoproteins is required for the uncontrolled cellular proliferation. In the present study we report the design and experimental testing of a recombinant multi-epitope protein containing immunogenic epitopes of HPV-16 E6 and E7. Tumor preventive assays, based on the engraftment of TC-1 cells in mice, showed that the E6E7 multi-epitope protein induced a full preventive anti-tumor protection in wild-type mice, as well as in mice deficient in expression of CD4+ T cells and TLR4 receptor. Nonetheless, no anti-tumor protection was observed in mice deficient in CD8+ T cells. Also, the vaccine promoted high activation of E6/E7-specific T cells and in a therapeutic-approach, E6E7 protein conferred full anti-tumor protection in mice. These results show a potential use of this E6E7 multi-epitope antigen as a new and promising antigen for the development of a therapeutic vaccine against tumors induced by HPV. PMID:26390407

  3. Mechanistic Analysis of the Role of Bromodomain-containing Protein 4 (BRD4) in BRD4-NUT Oncoprotein-induced Transcriptional Activation*

    PubMed Central

    Wang, Ranran; You, Jianxin

    2015-01-01

    NUT midline carcinoma (NMC) is a rare but highly aggressive cancer typically caused by the translocation t(15;19), which results in the formation of the BRD4-NUT fusion oncoprotein. Previous studies have demonstrated that fusion of the NUT protein with the double bromodomains of BRD4 may significantly alter the cellular gene expression profile to contribute to NMC tumorigenesis. However, the mechanistic details of this BRD4-NUT function remain poorly understood. In this study, we examined the NUT function in transcriptional regulation by targeting it to a LacO transgene array integrated in U2OS 2-6-3 cells, which allow us to visualize how NUT alters the in situ gene transcription dynamic. Using this system, we demonstrated that the NUT protein tethered to the LacO locus recruits p300/CREB-binding protein (CBP), induces histone hyperacetylation, and enriches BRD4 to the transgene array chromatin foci. We also discovered that, in BRD4-NUT expressed in NMC cells, the NUT moiety of the fusion protein anchored to chromatin by the double bromodomains also stimulates histone hyperacetylation, which causes BRD4 to bind tighter to chromatin. Consequently, multiple BRD4-interacting factors are recruited to the NUT-associated chromatin locus to activate in situ transgene expression. This gene transcription function was repressed by either expression of a dominant negative inhibitor of the p300-NUT interaction or treatment with (+)-JQ1, which dissociates BRD4 from the LacO chromatin locus. Our data support a model in which BRD4-NUT-stimulated histone hyperacetylation recruits additional BRD4 and interacting partners to support transcriptional activation, which underlies the BRD4-NUT oncogenic mechanism in NMC. PMID:25512383

  4. Use of a rapid, efficient inoculation method to induce papillomas by cottontail rabbit papillomavirus DNA shows that the E7 gene is required.

    PubMed Central

    Brandsma, J L; Yang, Z H; Barthold, S W; Johnson, E A

    1991-01-01

    A simple inoculation method to induce papillomas efficiently with cottontail rabbit papillomavirus (CRPV) DNA is described. Using a jet injector, recombinant CRPV DNA is easily delivered to 100 or more sites per rabbit and induces typical epithelial papillomas in approximately 50% of those sites. Papillomas begin to form by 3 weeks and continue to develop for up to 7 weeks, a pattern similar to that reported following infection with intact virus. This system readily lends itself to investigation of viral gene function by delivering mutant viral genomes into an immunologically intact host. Two mutations in the E7 open reading frame were introduced into the complete CRPV genome and analyzed by this method. One was a frameshift mutation encoding just nine amino-terminal amino acids of the E7 protein; the other was an in-frame insertion mutation at position 9. Both E7 mutations were in a region of homology to the 300-kDa protein binding domain of adenovirus E1A protein. Neither mutant construct was able to induce papillomas, thereby demonstrating that the E7 gene participates in this biologic function. Exploitation of this approach, which demonstrates that a papillomavirus E7 gene is involved in the induction of papillomas in vivo, should permit detailed studies into molecular mechanisms involved in papilloma induction, malignant conversion, and host immune response. The high efficiency of papilloma induction with recombinant CRPV DNA suggests that the jet injector can also be used to study the biologic effects of other genetic elements in rabbits or in other species. Images PMID:1647019

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

    PubMed

    Scheffner, Martin; Whitaker, Noel J

    2003-02-01

    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

  6. Oncoprotein mdig contributes to silica-induced pulmonary fibrosis by altering balance between Th17 and Treg T cells

    PubMed Central

    Sun, Jiaying; Zhang, Yadong; Lu, Yongju; Battelli, Lori; Porter, Dale W.; Chen, Fei

    2015-01-01

    Mineral dust-induced gene (mdig, also named Mina53) was first identified from alveolar macrophages of the coal miners with chronic lung inflammation or fibrosis, but how this gene is involved in lung diseases is poorly understood. Here we show that heterozygotic knockout of mdig (mdig+/−) ameliorates silica-induced lung fibrosis by altering the balance between Th17 cells and Treg cells. Relative to the wild type (WT) mice, infiltration of the macrophages and Th17 cells was reduced in lungs from silica-exposed mdig+/− mice. In contrast, an increased infiltration of the T regulatory (Treg) cells to the lung intestitium was observed in the mdig+/− mice treated with silica. Both the number of Th17 cells in the lung lymph nodes and the level of IL-17 in the bronchoalveolar lavage fluids were decreased in the mdig+/− mice in response to silica. Thus, these results suggest that mdig may contribute to silica-induced lung fibrosis by altering the balance between Th17 and Treg cells. Genetic deficiency of mdig impairs Th17 cell infiltration and function, but favors infiltration of the Treg cells, the immune suppressive T cells that are able to limit the inflammatory responses by repressing the Th17 cells and macrophages. PMID:25669985

  7. Interleukin 24 is induced by the RET/PTC3 oncoprotein and is an autocrine growth factor for epithelial cells.

    PubMed

    Shinohara, Shogo; Rothstein, Jay L

    2004-09-30

    Thyroid cancers, like hematological malignancies, are commonly associated with chromosomal translocations leading to the formation of fusion proteins. Through altered signaling by fusion proteins, cell death and survival pathways are disrupted and the physiological balance of cell-cell communication may be lost. A consequence of this disruption is the release of factors by stressed cells that alert the host. One type of host response is leukocytic infiltration that may develop into chronic inflammation or autoimmune disease. Although inflammation can be associated with neoplastic tissue, the mechanism driving this process is largely unknown. Therefore, to address the mechanism of cancer inflammation we investigated the effects of an oncogene in a murine model system. A comprehensive genetic analysis revealed several soluble factors that were induced by RET/papillary thyroid carcinoma (PTC)3 gene expression including several proinflammatory cytokines, chemokines and immunologically relevant costimulatory molecules. Following a large genetic screen using RP3-expressing thyroid cells, we identified a highly abundant transcript and later identified it as interleukin 24 (Il24), a cytokine with diverse tumor suppressor and inflammatory activities. We show that RET/PTC3 induces Il24 expression in rat thyrocytes and that this expression is dependent on the signaling properties of its tyrosine kinase. Likewise, RET/PTC3 induces large amounts of Il24 following expression in murine thyrocytes, but its expression is dramatically reduced in poorly differentiated carcinomas, a finding that parallels the loss of RET/PTC3 expression. Consistent with its behavior as a tumor suppressor, the loss of Il24 coincided with the loss of RET/PTC3 in poorly differentiated mouse tumors. A functional role of Il24 in the autocrine growth/survival of RET/PTC3-expressing thyroid cells was identified helping to support its role in cellular transformation. These data suggest that the induction of

  8. Histopathological changes induced by selective inactivation of menin on the thyroid gland in RET÷PTC3 and E7 transgenic mice. A study of 77 cases.

    PubMed

    Căpraru, Oana Maria; Berger, Nicole; Gadot, Nicolas; Decaussin-Petrucci, Myriam; Zhang, Chang; Borda, Angela; Szilágyi, Tibor; Borson-Chazot, Françoise; Selmi-Ruby, Samia

    2016-01-01

    Multiple Endocrine Neoplasia Type 1 (MEN1) does not involve the thyroid gland, but animal studies have shown that mice with inactivation of menin could develop thyroid pathologies. The objective was to evaluate if the selective inactivation of menin in murine thyroid glands expressing RET÷PTC3 and E7 oncogenes, might induce an increased index of proliferation and a more rapid development of thyroid hyperplasia and÷or tumors. The thyroid glands of 77 mice aged 4-18 months (31 expressing the E7 oncogene and 25 the RET÷PTC3 oncogene) were analyzed for histological changes and Ki67 proliferation index. Fifty-two mice had selective inactivation of menin in the thyroid gland (16 mice with RET÷PTC3 oncogene and 19 mice with E7 oncogene). As compared to wild type, mice with inactivation of menin presented an increased Ki67 proliferation index. Mice presenting the E7 oncogene showed larger thyroid glands with a pattern of diffuse hyperplasia. Mice expressing the RET÷PTC3 oncogene presented larger thyroid glands compared to the wild type mice but smaller compared to E7 mice. The lesions in the RET÷PTC3 group were "proliferative papillary cystic changes" (60%), "cribriform" (16%), "solid" (8%) and a combination of these patterns in the rest of the thyroid glands. The inactivation of menin in the thyroid gland of young mice does not seem to change the histological pattern, but it influences the proliferation of follicular cells. Further molecular studies especially in aged mice are needed to better understand the correlation between certain oncogenes and the inactive status of menin. PMID:27151693

  9. Novel Functions of the Human Papillomavirus E6 Oncoproteins.

    PubMed

    Wallace, Nicholas A; Galloway, Denise A

    2015-11-01

    Human papillomaviruses (HPVs) infect the epidermis as well as mucous membranes of humans. They are the causative agents of anogenital tract and some oropharyngeal cancers. Infections begin in the basal epithelia, where the viral genome replicates slowly along with its host cell. As infected cells begin to differentiate and progress toward the periphery, the virus drives proliferation in cells that would otherwise be quiescent. To uncouple differentiation from continued cellular propagation, HPVs express two oncoproteins, HPV E6 and E7. This review focuses on high-risk α-HPV E6, which in addition to supporting viral replication has transforming properties. HPV E6 promotes p53 degradation and activates telomerase, but the multifaceted oncoprotein has numerous other functions that are highlighted here. PMID:26958922

  10. Effect of human papillomavirus 16 oncoproteins on oncostatin M upregulation in oral squamous cell carcinoma.

    PubMed

    Chuerduangphui, Jureeporn; Pientong, Chamsai; Chaiyarit, Ponlatham; Patarapadungkit, Natcha; Chotiyano, Apinya; Kongyingyoes, Bunkerd; Promthet, Supannee; Swangphon, Piyawut; Wongjampa, Weerayut; Ekalaksananan, Tipaya

    2016-08-01

    Human papillomavirus (HPV) infection modulates several host cytokines contributing to cancer development. Oncostatin M (OSM), an IL-6 family cytokine, acts to promote cell senescence and inhibit growth. Its dysregulation promotes cell survival, cell proliferation and metastasis in various malignancies. The effect of HPV on OSM dysregulation has not been investigated. To elucidate this, immunohistochemistry was used on formalin-fixed, paraffin-embedded oral squamous cell carcinoma (OSCC) tissues: HPV-positive (50) and HPV-negative (50) cases. Immortalized human cervical keratinocytes expressing HPV16E6 (HCK1T, Tet-On system) were used to demonstrate the role of HPV16E6 in OSM expression. In addition, a vector containing HPV16E6/E7 was transiently transfected into oral cancer cell lines. Cell viability, cell-cycle progression and cell migration were evaluated using flow cytometry and a wound healing assay, respectively. The results showed various intensities of OSM expression in OSCC. Interestingly, the median percentages of strongly stained cells were significantly higher in HPV-positive OSCCs than in HPV-negative OSCCs. To explore the role of HPV oncoproteins on OSM expression, the expression of HPV16E6 in the HCK1T Tet-On condition was induced by doxycycline and HPV16E6 was found to significantly upregulate levels of OSM mRNA and protein, with concomitant upregulation of c-Myc. In addition, the levels of OSM mRNA and protein in E6/E7 transiently transfected oral cancer cells also gradually increased in a time-dependent manner and these transfected cells showed greater viability and higher migration rates and cell-cycle progression than controls. This result demonstrates that HPV16 oncoproteins upregulate OSM and play an important role to promote OSCC development. PMID:27349249

  11. Characterization of Epithelial Progenitors in Normal Human Palatine Tonsils and Their HPV16 E6/E7-Induced Perturbation

    PubMed Central

    Kang, Sung Yoon Catherine; Kannan, Nagarajan; Zhang, Lewei; Martinez, Victor; Rosin, Miriam P.; Eaves, Connie J.

    2015-01-01

    Summary Human palatine tonsils are oropharyngeal lymphoid tissues containing multiple invaginations (crypts) in which the continuity of the outer surface epithelium is disrupted and the isolated epithelial cells intermingle with other cell types. We now show that primitive epithelial cells detectable in vitro in 2D colony assays and in a 3D culture system are CD44+NGFR+ and present in both surface and crypt regions. Transcriptome analysis indicated a high similarity between CD44+NGFR+ cells in both regions, although those isolated from the crypt contained a higher proportion of the most primitive (holo)clonogenic cells. Lentiviral transduction of CD44+NGFR+ cells from both regions with human papillomavirus 16-encoded E6/E7 prolonged their growth in 2D cultures and caused aberrant differentiation in 3D cultures. Our findings therefore reveal a shared, site-independent, hierarchical organization, differentiation potential, and transcriptional profile of normal human tonsillar epithelial progenitor cells. They also introduce a new model for investigating the mechanisms of their transformation. PMID:26527383

  12. Protein vaccination with HPV16 E7/Pep-1 nanoparticles elicits a protective T-helper cell-mediated immune response.

    PubMed

    Mardani, Golnaz; Bolhassani, Azam; Agi, Elnaz; Shahbazi, Sepideh; Mehdi Sadat, Seyed

    2016-06-01

    Two human papillomavirus (HPV) viral oncoproteins, E6 and E7 represent ideal targets for development of a therapeutic HPV vaccine. It is important to reduce the rate of HPV-associated malignancies through improvement of vaccine modalities. In this study, we used a short amphipathic peptide carrier, Pep-1, for delivery of the full-length HPV16 E7 protein into mammalian cells and evaluated immune responses and protective effects of different formulations in C57BL/6 tumor mice model. Our results showed that the complexes of E7/Pep-1 protein form stable nanoparticles through noncovalent binding with an average size of 120 to 250 nm. The efficient delivery of E7 protein by Pep-1 at molar ratio of 1:20 was detected in HEK-293T cell line for 1 h and 3 h post-transfection. Immunization with E7/Pep-1 nanoparticles at a ratio of 1:20 induced a higher Th1 cellular immune response with the predominant IgG2a and IFN-γ levels than those induced by E7 protein in a murine tumor model. These data suggest that Pep-1 peptide would indicate promising applications for improvement of HPV therapeutic vaccines. © 2016 IUBMB Life, 68(6):459-467, 2016. PMID:27094221

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed Central

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

    2012-01-01

    The human papillomavirus (HPV) E7 oncoprotein binds cellular factors, preventing or retargeting their function and thereby making the infected cell conducive for viral replication. A key target of E7 is the product of the retinoblastoma susceptibility locus (pRb). This interaction results in the release of E2F transcription factors and drives the host cell into the S phase of the cell cycle. E7 binds pRb via a high-affinity binding site in conserved region 2 (CR2) and also targets a portion of cellular pRb for degradation via the proteasome. Evidence suggests that a secondary binding site exists in CR3, and that this interaction influences pRb deregulation. Additionally, evidence suggests that CR3 also participates in the degradation of pRb. We have systematically analyzed the molecular mechanisms by which CR3 contributes to deregulation of the pRb pathway by utilizing a comprehensive series of mutations in residues predicted to be exposed on the surface of HPV16 E7 CR3. Despite differences in the ability to interact with cullin 2, all CR3 mutants degrade pRb comparably to wild-type E7. We identified two specific patches of residues on the surface of CR3 that contribute to pRb binding independently of the high-affinity CR2 binding site. Mutants within CR3 that affect pRb binding are less effective than the wild-type E7 in overcoming pRb-induced cell cycle arrest. This demonstrates that the interaction between HPV16 E7 CR3 and pRb is functionally important for alteration of the cell cycle. PMID:23015707

  15. Disc large 1 expression is altered by human papillomavirus E6/E7 proteins in organotypic cultures of human keratinocytes.

    PubMed

    Valdano, M Bugnon; Cavatorta, A L; Morale, M G; Marziali, F; de Souza Lino, V; Steenbergen, R D M; Boccardo, E; Gardiol, D

    2016-02-01

    Loss of cell polarity is a fundamental process in cell transformation. Among polarity proteins, we focused on human disc large (DLG1), which is localized mainly at adherens junctions and contributes to the control of cell proliferation. We previously demonstrated that its expression is altered in HPV-associated cervical neoplastic lesions, but the mechanisms beyond this remain unknown. In this study, we analysed the contribution of HPV proteins to the changes in DLG1 expression in the squamous epithelium. We observed tissue and intracellular misdistribution of DLG1 when high-risk HPV-18 E7 or E6/E7 proteins were expressed in organotypic raft cultures. The viral oncoproteins induce the loss of DLG1 from the cell borders and an increase in the level of DLG1 protein, reflecting the pattern observed in cervical lesions. These findings were corroborated in cultures bearing the entire HPV-18 genome. Interestingly, changes in tissue distribution and abundance of DLG1 were also detected in organotypic cultures expressing the low-risk HPV-11 E7 or E6/E7 proteins, suggesting a conserved function among different HPV types. However, for low-risk HPVs, the subcellular localization of DLG1 at cell-to-cell contacts was predominantly maintained. This report offers new evidence, we believe, of the involvement of HPV proteins in DLG1 expression pattern and our data support previous observations regarding DLG1 expression in cervical lesions. PMID:26653181

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

    PubMed Central

    Gao, Qingshen; Srinivasan, Seetha; Boyer, Sarah N.; Wazer, David E.; Band, Vimla

    1999-01-01

    The high-risk human papillomaviruses (HPVs) are associated with carcinomas of the cervix and other genital tumors. Previous studies have identified two viral oncoproteins, E6 and E7, which are expressed in the majority of HPV-associated carcinomas. The ability of high-risk HPV E6 protein to immortalize human mammary epithelial cells (MECs) has provided a single-gene model to study the mechanisms of E6-induced oncogenic transformation. In this system, the E6 protein targets the p53 tumor suppressor protein for degradation, and mutational analyses have shown that E6-induced degradation of p53 protein is required for MEC immortalization. However, the inability of most dominant-negative p53 mutants to induce efficient immortalization of MECs suggests the existence of additional targets of the HPV E6 oncoprotein. Using the yeast two-hybrid system, we have isolated a novel E6-binding protein. This polypeptide, designated E6TP1 (E6-targeted protein 1), exhibits high homology to GTPase-activating proteins for Rap, including SPA-1, tuberin, and Rap1GAP. The mRNA for E6TP1 is widely expressed in tissues and in vitro-cultured cell lines. The gene for E6TP1 localizes to chromosome 14q23.2-14q24.3 within a locus that has been shown to undergo loss of heterozygosity in malignant meningiomas. Importantly, E6TP1 is targeted for degradation by the high-risk but not the low-risk HPV E6 proteins both in vitro and in vivo. Furthermore, the immortalization-competent but not the immortalization-incompetent HPV16 E6 mutants target the E6TP1 protein for degradation. Our results identify a novel target for the E6 oncoprotein and provide a potential link between HPV E6 oncogenesis and alteration of a small G protein signaling pathway. PMID:9858596

  17. Quercetin induces structural chromosomal aberrations and uncommon rearrangements in bovine cells transformed by the E7 protein of bovine papillomavirus type 4.

    PubMed

    Leal, A M; Ferraz, O P; Carvalho, C; Freitas, A C; Beniston, R G; Beçak, W; Campo, M S; Stocco dos Santos, R C

    2003-03-01

    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. PMID:19379326

  18. Oncoprotein stability after tumour resection.

    PubMed Central

    Ong, G.; Gullick, W.; Sikora, K.

    1990-01-01

    The means by which oncogenes and their products activate malignant transformation are currently under intense investigation. However, published papers on experiments using human tumour material do not always report in detail their methods of collection or storage of the specimens. In order to assess the stability of oncogene encoded proteins following collection or storage of human tumour biopsies, we have examined the rate of decay of the c-myc, neu and EGF-receptor proteins. Solid tumours, containing amplified copies of each oncogene, were established in nude mice and the stability of the oncogene protein in portions of each tumour, left in phosphate buffered saline at room temperature for varying time intervals, was examined by immunoblotting. Intact EGF-receptor and neu oncoproteins were present even after 24 h under these conditions while the c-myc protein was apparently rapidly degraded after 20 min. These data demonstrate that oncogene products decay at different rates after tumour resection and that collection of human biopsies should take this into account in order to provide the basis for consistent measurements of protein expression. Images Figure 1 Figure 2 Figure 3 PMID:2139576

  19. Design of a highly effective therapeutic HPV16 E6/E7-specific DNA vaccine: optimization by different ways of sequence rearrangements (shuffling).

    PubMed

    Almajhdi, Fahad N; Senger, Tilo; Amer, Haitham M; Gissmann, Lutz; Öhlschläger, Peter

    2014-01-01

    Persistent infection with the high-risk Human Papillomavirus type 16 (HPV 16) is the causative event for the development of cervical cancer and other malignant tumors of the anogenital tract and of the head and neck. Despite many attempts to develop therapeutic vaccines no candidate has entered late clinical trials. An interesting approach is a DNA based vaccine encompassing the nucleotide sequence of the E6 and E7 viral oncoproteins. Because both proteins are consistently expressed in HPV infected cells they represent excellent targets for immune therapy. Here we report the development of 8 DNA vaccine candidates consisting of differently rearranged HPV-16 E6 and E7 sequences within one molecule providing all naturally occurring epitopes but supposedly lacking transforming activity. The HPV sequences were fused to the J-domain and the SV40 enhancer in order to increase immune responses. We demonstrate that one out of the 8 vaccine candidates induces very strong cellular E6- and E7- specific cellular immune responses in mice and, as shown in regression experiments, efficiently controls growth of HPV 16 positive syngeneic tumors. This data demonstrates the potential of this vaccine candidate to control persistent HPV 16 infection that may lead to malignant disease. It also suggests that different sequence rearrangements influence the immunogenecity by an as yet unknown mechanism. PMID:25422946

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

    SciTech Connect

    Azzimonti, Barbara; Dell'Oste, Valentina; Borgogna, Cinzia; Mondini, Michele; Gugliesi, Francesca; De Andrea, Marco; Chiorino, Giovanna; Scatolini, Maria; Ghimenti, Chiara; Landolfo, Santo; Gariglio, Marisa

    2009-06-05

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

  1. Interleukin-12-secreting human papillomavirus type 16-transformed cells provide a potent cancer vaccine that generates E7-directed immunity.

    PubMed

    Hallez, S; Detremmerie, O; Giannouli, C; Thielemans, K; Gajewski, T F; Burny, A; Leo, O

    1999-05-01

    The development of a vaccine that would be capable of preventing or curing the (pre)cancerous lesions induced by genital oncogenic human papillomaviruses (HPVs) is the focus of much research. Many studies are presently evaluating vaccines based on the viral E6 and E7 oncoproteins, both of which are continually expressed by tumor cells. The success of a cancer vaccine relies, in large part, on the induction of a tumor-specific Th1-type immunity. In this study, we have evaluated the ability of B7-related and/or interleukin-12 (IL-12)-expressing, non-immunogenic murine HPV16-transformed BMK-16/myc cells, to achieve this goal. BMK-16/myc cells engineered to express surface B7-1 or B7-2 molecules remain tumorigenic in syngeneic BALB/c mice, suggesting that expression of these molecules alone is not sufficient to induce tumor regression. In contrast, mice injected with tumor cells engineered to secrete IL-12 remained tumor-free, demonstrating that IL-12 expression is sufficient to induce tumor rejection. IL-12-secreting BMK-16/myc cells were further shown to induce potent and specific long-term tumor resistance, even after irradiation. B7-1 was found to slightly but systematically improve anti-tumor immunity elicited by IL-12-secreting BMK-16/myc cells. Injection of irradiated B7-1/IL-12+ BMK-16/myc cells generates long-lasting, Th1-type, BMK-16/myc-directed immunity in tumor-resistant mice. These mice display a memory-type, E7-specific, cell-mediated immune response, which is potentially significant for clinical applications. PMID:10209958

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

    PubMed Central

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

    2015-01-01

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

  3. A LONGITUDINAL STUDY OF HPV16 L1, E6 AND E7 SEROPOSITIVITY AND ORAL HPV16 INFECTION

    PubMed Central

    Beachler, Daniel C.; Viscidi, Raphael; Sugar, Elizabeth A.; Minkoff, Howard; Strickler, Howard D.; Cranston, Ross D.; Wiley, Dorothy J.; Jacobson, Lisa P.; Weber, Kathleen M.; Margolick, Joseph B.; Reddy, Susheel; Gillison, Maura L.; D’Souza, Gypsyamber

    2014-01-01

    Background Individuals with HPV infections can develop IgG antibodies to HPV proteins including the L1 capsid and E6 and E7 oncoproteins. Evidence on whether L1 antibodies reduce the risk of cervical HPV infection is mixed, but this has not been explored for oral HPV infections. Antibodies to HPV16’s E6 oncoprotein have been detected in some oropharyngeal cancer cases years prior to cancer diagnosis, but it is unknown if these antibodies are associated with oral HPV16 DNA. Methods Enzyme linked immunosorbent assays tested for serum antibodies to HPV16’s L1 capsid in 463 HIV-infected and 293 HIV-uninfected adults, and for antibodies to recombinantly expressed E6 and E7 oncoproteins to HPV16 in 195 HIV-infected and 69 HIV-uninfected cancer-free participants at baseline. Oral rinse samples were collected semi-annually for up to three years and tested for HPV DNA using PGMY 09/11 primers. Adjusted Poisson, logistic, and Wei-Lin-Weissfeld regression models were utilized. Results HPV16 L1 seroreactivity did not reduce the subsequent risk of incident oral HPV16 infection in unadjusted (HR=1.4, 95%CI=0.59–3.3) or adjusted (aHR=1.1, 95%CI=0.41–3.0) analysis. Antibodies to HPV16 E6 and E7 oncoproteins were detected in 7.6% and 3.4% of participants respectively, but they were not associated with baseline oral HPV16 DNA prevalence or oral HPV16 persistence (each p-value>0.40). Conclusions Naturally acquired HPV16 L1 antibodies did not reduce the risk of subsequent oral HPV16 infection. HPV16 E6 and E7 seropositivity was not a marker for oral HPV16 infection in this population without HPV-related cancer. PMID:25585068

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

    SciTech Connect

    Krawczyk, Ewa; Hanover, John A.; Schlegel, Richard; Suprynowicz, Frank A.

    2008-07-11

    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.

  5. Mutual regulation between deubiquitinase CYLD and retroviral oncoprotein Tax

    PubMed Central

    2011-01-01

    Background Oncoprotein Tax, encoded by the human T-cell leukemia virus type 1 (HTLV1), persistently induces NF-κB activation, which contributes to HTLV1-mediated T-cell transformation. Recent studies suggest that the signaling function of Tax requires its ubiquitination, although how the Tax ubiquitination is regulated remains unclear. Results We show here that the deubiquitinase CYLD physically interacts with Tax and negatively regulates the ubiquitination of this viral protein. This function of CYLD is associated with inhibition of Tax-mediated activation of IKK although not that of Tak1. Interestingly, CYLD undergoes constitutive phosphorylation in HTLV1-transformed T cells, a mechanism known to inactivate the catalytic activity of CYLD. Consistently, a phospho-mimetic CYLD mutant fails to inhibit Tax ubiquitination. Conclusion These findings suggest that CYLD negatively regulates the signaling function of Tax through inhibition of Tax ubiquitination. Conversely, induction of CYLD phosphorylation may serve as a mechanism by which HTLV1 overrides the inhibitory function of CYLD, leading to the persistent activation of NF-κB. PMID:21824392

  6. Functional diversity and mutational analysis of Agrobacterium 6B oncoproteins.

    PubMed

    Helfer, A; Pien, S; Otten, L

    2002-07-01

    Many Agrobacterium T-DNA genes belong to a diverse family of T-DNA genes, the rolB family. These genes cause various growth abnormalities but their modes of action remain largely unknown. So far, none of the RolB-like proteins has been subjected to mutational analysis. The RolB-like oncoprotein 6B, which induces tumours on species such as Nicotiana glauca and Kalanchoe tubiflora, was chosen to investigate the role of the most conserved amino acid residues within the RolB family. We first determined which of the natural 6B variants had the strongest oncogenic activity; to this end, six 6b coding sequences (A- 6b, AB- 6b, C- 6b, CG- 6b, S- 6b and T- 6b) were placed under the control of the strong constitutive 2x35S promoter and compared for tumour induction on N. glauca, N. tabacum and K. daigremontiana. Oncogenicity increased in the order C- 6b/CG- 6b, A- 6b/AB- 6b, and S- 6b/T- 6b. The most conserved amino acid residues in the strongly oncogenic T-6B protein were mutated and shown to be required for oncogenicity and accumulation of the T-6B protein in planta but not in bacteria. Hybrids between T-6B and the weakly oncogenic A-6B protein revealed an additional oncogenic determinant required for the formation of large tumours. PMID:12172796

  7. The Viral Oncoprotein HBx of Hepatitis B virus Promotes the Growth of Hepatocellular Carcinoma through Cooperating with the Cellular Oncoprotein RMP

    PubMed Central

    Wang, Qi; Xu, Yi; Zhou, Wei; Zhong, Lei; Wen, Zengqing; Yu, Huijun; Chen, Shaomu; Shen, Jian; Chen, Han; She, Qinying; Jiang, Jingting; Miao, Jingcheng; Wei, Wenxiang

    2014-01-01

    The smallest gene HBx of Hepatitis B virus (HBV) is recognized as an important viral oncogene (V-oncogene) in the hepatocarcinogenesis. Our previous work demonstrated that RMP is a cellular oncogene (C-oncogene) required for the proliferation of hepatocellular carcinoma (HCC) cells. Here we presented the collaboration between V-oncogene HBx and C-oncogene RMP in the development of HCC. The coexpression of HBx and RMP resulted in the cooperative effect of antiapoptosis and proliferation of HCC cells. In vivo, overexpression of RMP accelerated the growth of HBx-induced xenograft tumors in nude mice and vice versa HBx promoted the growth of RMP-driven xenograft tumors. Although HBx didn't regulate the expression of RMP, HBx and RMP interact with each other and collocalized in the cytoplasm of HCC cells. HBx and RMP collaboratively inhibited the expression of apoptotic factors and promoted the expression of antiapoptotic factors. This finding suggests that HBV may induce, or at least partially contributes to the carcinogenesis of HCC, through its V-oncoprotein HBx interacting with the C-oncoprotein RMP. PMID:25516716

  8. Identification of host transcriptional networks showing concentration-dependent regulation by HPV16 E6 and E7 proteins in basal cervical squamous epithelial cells

    PubMed Central

    Smith, Stephen P.; Scarpini, Cinzia G.; Groves, Ian J.; Odle, Richard I.; Coleman, Nicholas

    2016-01-01

    Development of cervical squamous cell carcinoma requires increased expression of the major high-risk human-papillomavirus (HPV) oncogenes E6 and E7 in basal cervical epithelial cells. We used a systems biology approach to identify host transcriptional networks in such cells and study the concentration-dependent changes produced by HPV16-E6 and -E7 oncoproteins. We investigated sample sets derived from the W12 model of cervical neoplastic progression, for which high quality phenotype/genotype data were available. We defined a gene co-expression matrix containing a small number of highly-connected hub nodes that controlled large numbers of downstream genes (regulons), indicating the scale-free nature of host gene co-expression in W12. We identified a small number of ‘master regulators’ for which downstream effector genes were significantly associated with protein levels of HPV16 E6 (n = 7) or HPV16 E7 (n = 5). We validated our data by depleting E6/E7 in relevant cells and by functional analysis of selected genes in vitro. We conclude that the network of transcriptional interactions in HPV16-infected basal-type cervical epithelium is regulated in a concentration-dependent manner by E6/E7, via a limited number of central master-regulators. These effects are likely to be significant in cervical carcinogenesis, where there is competitive selection of cells with elevated expression of virus oncoproteins. PMID:27457222

  9. Identification of host transcriptional networks showing concentration-dependent regulation by HPV16 E6 and E7 proteins in basal cervical squamous epithelial cells.

    PubMed

    Smith, Stephen P; Scarpini, Cinzia G; Groves, Ian J; Odle, Richard I; Coleman, Nicholas

    2016-01-01

    Development of cervical squamous cell carcinoma requires increased expression of the major high-risk human-papillomavirus (HPV) oncogenes E6 and E7 in basal cervical epithelial cells. We used a systems biology approach to identify host transcriptional networks in such cells and study the concentration-dependent changes produced by HPV16-E6 and -E7 oncoproteins. We investigated sample sets derived from the W12 model of cervical neoplastic progression, for which high quality phenotype/genotype data were available. We defined a gene co-expression matrix containing a small number of highly-connected hub nodes that controlled large numbers of downstream genes (regulons), indicating the scale-free nature of host gene co-expression in W12. We identified a small number of 'master regulators' for which downstream effector genes were significantly associated with protein levels of HPV16 E6 (n = 7) or HPV16 E7 (n = 5). We validated our data by depleting E6/E7 in relevant cells and by functional analysis of selected genes in vitro. We conclude that the network of transcriptional interactions in HPV16-infected basal-type cervical epithelium is regulated in a concentration-dependent manner by E6/E7, via a limited number of central master-regulators. These effects are likely to be significant in cervical carcinogenesis, where there is competitive selection of cells with elevated expression of virus oncoproteins. PMID:27457222

  10. The fibronectin/α3β1 integrin axis serves as molecular basis for keratinocyte invasion induced by βHPV.

    PubMed

    Heuser, S; Hufbauer, M; Steiger, J; Marshall, J; Sterner-Kock, A; Mauch, C; Zigrino, P; Akgül, B

    2016-08-25

    Organ-transplant-recipients exhibit cancerization of the skin from which multiple human papillomavirus (HPV)-positive squamous cell carcinomas (SCCs) arise. However, the molecular basis for HPV-induced invasion of skin keratinocytes is not known. We generated a transgenic mouse model expressing the E7 oncoprotein of HPV8 in the murine epidermis under the control of the keratin-14 promoter and showed that E7 is carcinogenic in mice. We further showed that both, the E7-expressing keratinocyte and mesenchymal components of the extracellular matrix as critical in eliciting the invasive behavior. E7 expression in basal keratinocytes, grown on fibronectin, led to epithelial-mesenchymal transition mediated by a cadherin switch. E7-positive keratinocytes displayed enhanced EDA-fibronectin expression and secretion and stimulated dermal fibroblasts to express EDA-fibronectin. Deposition of fibronectin was also detected in the peritumoral stroma of HPV8-positive skin SCC. When grown on fibronectin, E7-positive keratinocytes, in particular stem cell-like cells, exhibited increased cell surface levels of the α3-integrin chain. Functional blocking confirmed α3 as a critical molecule sufficient to induce E7-mediated invasion. This mechanistic link is further supported by expression of an E7-mutant, impaired in targeting α3 to the cell surface. These findings highlight the importance of epithelial-extracellular matrix interaction required for keratinocyte invasion and provide further mechanistic evidence for a role of HPV in skin carcinogenesis. PMID:26804167

  11. Intravaginal HPV DNA vaccination with electroporation induces local CD8+ T-cell immune responses and antitumor effects against cervicovaginal tumors

    PubMed Central

    Sun, Y; Peng, S; Qiu, J; Miao, J; Yang, B; Jeang, J; Hung, C-F; Wu, T-C

    2015-01-01

    Therapeutic human papillomavirus (HPV) vaccines have the potential to inhibit the progression of an established HPV infection to precancer and cancer lesions by targeting HPV oncoproteins. We have previously developed a therapeutic DNA vaccine encoding calreticulin (CRT) linked to E7, CRT/E7 DNA vaccine, for use in the treatment of HPV-associated lesions. Since the transfection efficiency of DNA vaccines administered in vivo is typically low, we examined the use of electroporation as well as different routes of administration to enhance antigen-specific tumor control. We tested the effects of the CRT/E7 DNA vaccine administered intramuscularly or intravaginally, with or without electroporation, on the generation of CD8+ T-cell immunity and therapeutic antitumor effects in HPV16 E7-expressing cervicovaginal tumor-bearing mice. We found that intravaginal vaccination of CRT/E7 DNA followed by electroporation-induced potent E7-specific CD8+ T-cell responses in the cervicovaginal tract, compared with intramuscular injection followed by electroporation. Furthermore, tumor-bearing mice vaccinated intravaginally followed by electroporation had an enhanced survival, antitumor effects and local production of IFN-γ+CD8+ T cells compared with those vaccinated intramuscularly with electroporation. Thus, we show that intravaginal CRT/E7 DNA vaccination followed by electroporation generates the most potent therapeutic antitumor effects against an orthotopic E7-expressing tumor model. The current study will have significant clinical implications once a clinically applicable electroporation device for intravaginal use becomes available. PMID:25786869

  12. MicroRNA-331-3p Suppresses Cervical Cancer Cell Proliferation and E6/E7 Expression by Targeting NRP2.

    PubMed

    Fujii, Tomomi; Shimada, Keiji; Asano, Aya; Tatsumi, Yoshihiro; Yamaguchi, Naoko; Yamazaki, Masaharu; Konishi, Noboru

    2016-01-01

    Aberrant expression of microRNAs (miRNAs) is involved in the development and progression of various types of cancers. In this study, we investigated the role of miR-331-3p in cell proliferation and the expression of keratinocyte differentiation markers of uterine cervical cancer cells. Moreover, we evaluated whether neuropilin 2 (NRP2) are putative target molecules that regulate the human papillomavirus (HPV) related oncoproteins E6 and E7. Cell proliferation in the human cervical cancer cell lines SKG-II, HCS-2, and HeLa was assessed using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. Cellular apoptosis was measured using the TdT-mediated dUTP nick end labeling (TUNEL) and Annexin V assays. Quantitative RT-PCR was used to measure the messenger RNA (mRNA) expression of the NRP2, E6, E7, p63, and involucrin (IVL) genes. A functional assay for cell growth was performed using cell cycle analyses. Overexpression of miR-331-3p inhibited cell proliferation, and induced G2/M phase arrest and apoptosis in SKG-II, HCS-2 and HeLa cells. The luciferase reporter assay of the NRP2 3'-untranslated region revealed the direct regulation of NRP2 by miR-331-3p. Gene expression analyses using quantitative RT-PCR in SKG-II, HCS-2, and HeLa cells overexpressing miR-331-3p or suppressing NRP2 revealed down-regulation of E6, E7, and p63 mRNA and up-regulation of IVL mRNA. Moreover, miR-331-3p overexpression was suppressed NRP2 expression in protein level. We showed that miR-331-3p and NRP2 were key effectors of cell proliferation by regulating the cell cycle, apoptosis. NRP-2 also regulates the expression of E6/E7 and keratinocyte differentiation markers. Our findings suggest that miR-331-3p has an important role in regulating cervical cancer cell proliferation, and that miR-331-3p may contribute to keratinocyte differentiation through NRP2 suppression. miR-331-3p and NRP2 may contribute to anti-cancer effects. PMID

  13. MicroRNA-331-3p Suppresses Cervical Cancer Cell Proliferation and E6/E7 Expression by Targeting NRP2

    PubMed Central

    Fujii, Tomomi; Shimada, Keiji; Asano, Aya; Tatsumi, Yoshihiro; Yamaguchi, Naoko; Yamazaki, Masaharu; Konishi, Noboru

    2016-01-01

    Aberrant expression of microRNAs (miRNAs) is involved in the development and progression of various types of cancers. In this study, we investigated the role of miR-331-3p in cell proliferation and the expression of keratinocyte differentiation markers of uterine cervical cancer cells. Moreover, we evaluated whether neuropilin 2 (NRP2) are putative target molecules that regulate the human papillomavirus (HPV) related oncoproteins E6 and E7. Cell proliferation in the human cervical cancer cell lines SKG-II, HCS-2, and HeLa was assessed using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. Cellular apoptosis was measured using the TdT-mediated dUTP nick end labeling (TUNEL) and Annexin V assays. Quantitative RT-PCR was used to measure the messenger RNA (mRNA) expression of the NRP2, E6, E7, p63, and involucrin (IVL) genes. A functional assay for cell growth was performed using cell cycle analyses. Overexpression of miR-331-3p inhibited cell proliferation, and induced G2/M phase arrest and apoptosis in SKG-II, HCS-2 and HeLa cells. The luciferase reporter assay of the NRP2 3′-untranslated region revealed the direct regulation of NRP2 by miR-331-3p. Gene expression analyses using quantitative RT-PCR in SKG-II, HCS-2, and HeLa cells overexpressing miR-331-3p or suppressing NRP2 revealed down-regulation of E6, E7, and p63 mRNA and up-regulation of IVL mRNA. Moreover, miR-331-3p overexpression was suppressed NRP2 expression in protein level. We showed that miR-331-3p and NRP2 were key effectors of cell proliferation by regulating the cell cycle, apoptosis. NRP-2 also regulates the expression of E6/E7 and keratinocyte differentiation markers. Our findings suggest that miR-331-3p has an important role in regulating cervical cancer cell proliferation, and that miR-331-3p may contribute to keratinocyte differentiation through NRP2 suppression. miR-331-3p and NRP2 may contribute to anti-cancer effects

  14. HPV16 oncoprotein regulates the translocation of β-catenin via activation of EGFR

    PubMed Central

    Hu, Zhongliang; Müller, Susan; Qian, Guoqin; Xu, Jing; Kim, Sungjin; Chen, Zhengjia; Jiang, Ning; Wang, Dongsheng; Zhang, Hongzheng; Saba, Nabil F.; Shin, Dong M.; Chen, Zhuo Georgia

    2014-01-01

    Background To understand the mechanism of frequent and early lymph node metastasis in high risk human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC), we investigated whether β-catenin is regulated by HPV oncoprotein and contributes to OPSCC metastasis. Methods Expression levels of p16, β-catenin, and epidermal growth factor receptor (EGFR) were examined in OPSCC samples (n=208) by immunohistochemistry. Expression and subcellular localization of β-catenin and EGFR activation were also studied in HPV-positive and -negative head and neck SCC cell lines by Western blot analysis. HPV16 E6 siRNA was used to elucidate the effect of HPV oncoprotein on β-catenin translocation. The involvement of EGFR in β-catenin translocation was confirmed by treatment with erlotinib. Moreover, the invasive capacity was evaluated after HPV16 E6/E7 repression. Results Our results showed that membrane weighted index (WI) of β-catenin was inversely correlated with p16 positivity (p<0.001) and lymph node metastasis (p=0.026), while nuclear staining of β-catenin was associated with p16-positive OPSCC (p<0.001). A low level of membrane β-catenin expression was significantly associated with disease free and overall survival (p<0.0001 in both cases). Furthermore, the membrane WI of EGFR was inversely correlated with p16 positivity (p<0.001) and positively correlated with membrane β-catenin (p<0.001). Our in vitro study showed that HPV16 E6 repression led to reductions of phosphoEGFR, and nuclear β-catenin, which were also observed after erlotinib treatment, and inhibition of invasion. Conclusions Our findings suggest that HPV16 E6 mediates the translocation of β-catenin to the nucleus, which may be regulated by activated EGFR. PMID:25209444

  15. The Ski oncoprotein interacts with the Smad proteins to repress TGFbeta signaling.

    PubMed

    Luo, K; Stroschein, S L; Wang, W; Chen, D; Martens, E; Zhou, S; Zhou, Q

    1999-09-01

    Smad proteins are critical signal transducers downstream of the receptors of the transforming growth factor-beta (TGFbeta) superfamily. On phosphorylation and activation by the active TGFbeta receptor complex, Smad2 and Smad3 form hetero-oligomers with Smad4 and translocate into the nucleus, where they interact with different cellular partners, bind to DNA, regulate transcription of various downstream response genes, and cross-talk with other signaling pathways. Here we show that a nuclear oncoprotein, Ski, can interact directly with Smad2, Smad3, and Smad4 on a TGFbeta-responsive promoter element and repress their abilities to activate transcription through recruitment of the nuclear transcriptional corepressor N-CoR and possibly its associated histone deacetylase complex. Overexpression of Ski in a TGFbeta-responsive cell line renders it resistant to TGFbeta-induced growth inhibition and defective in activation of JunB expression. This ability to overcome TGFbeta-induced growth arrest may be responsible for the transforming activity of Ski in human and avian cancer cells. Our studies suggest a new paradigm for inactivation of the Smad proteins by an oncoprotein through transcriptional repression. PMID:10485843

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

    SciTech Connect

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

    2007-10-10

    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.

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

    PubMed Central

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

    2011-01-01

    The human papillomavirus (HPV) E7 oncoprotein exists as a dimer and acts by binding to many cellular factors, preventing or retargeting their function and thereby making the infected cell conducive for viral replication. Dimerization of E7 is attributed primarily to the C-terminal domain, referred to as conserved region 3 (CR3). CR3 is highly structured and is necessary for E7's transformation ability. It is also required for binding of numerous E7 cellular targets. To systematically analyze the molecular mechanisms by which HPV16 E7 CR3 contributes to carcinogenesis, we created a comprehensive panel of mutations in residues predicted to be exposed on the surface of CR3. We analyzed our novel collection of mutants, as well as mutants targeting predicted hydrophobic core residues of the dimer, for the ability to dimerize. The same set of mutants was also assessed functionally for transformation capability in a baby rat kidney cell assay in conjugation with activated ras. We show that some mutants of HPV16 E7 CR3 failed to dimerize yet were still able to transform baby rat kidney cells. Our results identify several novel E7 mutants that abrogate transformation and also indicate that E7 does not need to exist as a stable dimer in order to transform cells. PMID:21775462

  18. Epstein-Barr Virus oncoprotein super-enhancers control B cell growth

    PubMed Central

    Zhou, Hufeng; Schmidt, Stefanie CS; Jiang, Sizun; Willox, Bradford; Bernhardt, Katharina; Liang, Jun; Johannsen, Eric C; Kharchenko, Peter; Gewurz, Benjamin E; Kieff, Elliott; Zhao, Bo

    2015-01-01

    Summary Super-enhancers are clusters of gene-regulatory sites bound by multiple transcription factors that govern cell transcription, development, phenotype, and oncogenesis. By examining Epstein-Barr virus (EBV) transformed lymphoblastoid cell lines (LCLs), we identified four EBV oncoproteins and five EBV-activated NF-κB subunits co-occupying ~1800 enhancer sites. Of these, 187 had markedly higher and broader histone H3K27ac signals characteristic of super-enhancers, and were designated “EBV super-enhancers”. EBV super-enhancer-associated genes included the MYC and BCL2 oncogenes, enabling LCL proliferation and survival. EBV super-enhancers were enriched for B cell transcription factor motifs and had a high co-occupancy of the transcription factors STAT5 and NFAT. EBV super-enhancer-associated genes were more highly expressed than other LCL genes. Disrupting EBV super-enhancers by the bromodomain inhibitor, JQ1 or conditionally inactivating an EBV oncoprotein or NF-κB decreased MYC or BCL2 expression and arrested LCL growth. These findings provide insight into mechanisms of EBV-induced lymphoproliferation and identify potential therapeutic interventions. PMID:25639793

  19. Epstein-Barr virus oncoprotein super-enhancers control B cell growth.

    PubMed

    Zhou, Hufeng; Schmidt, Stefanie C S; Jiang, Sizun; Willox, Bradford; Bernhardt, Katharina; Liang, Jun; Johannsen, Eric C; Kharchenko, Peter; Gewurz, Benjamin E; Kieff, Elliott; Zhao, Bo

    2015-02-11

    Super-enhancers are clusters of gene-regulatory sites bound by multiple transcription factors that govern cell transcription, development, phenotype, and oncogenesis. By examining Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (LCLs), we identified four EBV oncoproteins and five EBV-activated NF-κB subunits co-occupying ∼1,800 enhancer sites. Of these, 187 had markedly higher and broader histone H3K27ac signals, characteristic of super-enhancers, and were designated "EBV super-enhancers." EBV super-enhancer-associated genes included the MYC and BCL2 oncogenes, which enable LCL proliferation and survival. EBV super-enhancers were enriched for B cell transcription factor motifs and had high co-occupancy of STAT5 and NFAT transcription factors (TFs). EBV super-enhancer-associated genes were more highly expressed than other LCL genes. Disrupting EBV super-enhancers by the bromodomain inhibitor JQ1 or conditionally inactivating an EBV oncoprotein or NF-κB decreased MYC or BCL2 expression and arrested LCL growth. These findings provide insight into mechanisms of EBV-induced lymphoproliferation and identify potential therapeutic interventions. PMID:25639793

  20. How do oncoprotein mutations rewire protein-protein interaction networks?

    PubMed

    Bowler, Emily H; Wang, Zhenghe; Ewing, Rob M

    2015-01-01

    The acquisition of mutations that activate oncogenes or inactivate tumor suppressors is a primary feature of most cancers. Mutations that directly alter protein sequence and structure drive the development of tumors through aberrant expression and modification of proteins, in many cases directly impacting components of signal transduction pathways and cellular architecture. Cancer-associated mutations may have direct or indirect effects on proteins and their interactions and while the effects of mutations on signaling pathways have been widely studied, how mutations alter underlying protein-protein interaction networks is much less well understood. Systematic mapping of oncoprotein protein interactions using proteomics techniques as well as computational network analyses is revealing how oncoprotein mutations perturb protein-protein interaction networks and drive the cancer phenotype. PMID:26325016

  1. Tumorigenicity by human papillomavirus type 16 E6 and E7 in transgenic mice correlates with alterations in epithelial cell growth and differentiation.

    PubMed Central

    Griep, A E; Herber, R; Jeon, S; Lohse, J K; Dubielzig, R R; Lambert, P F

    1993-01-01

    The human papillomavirus type 16 (HPV-16) E6 and E7 oncogenes are thought to play a role in the development of most human cervical cancers. These E6 and E7 oncoproteins affect cell growth control at least in part through their association with and inactivation of the cellular tumor suppressor gene products, p53 and Rb. To study the biological activities of the HPV-16 E6 and E7 genes in epithelial cells in vivo, transgenic mice were generated in which expression of E6 and E7 was targeted to the ocular lens. Expression of the transgenes correlated with bilateral microphthalmia and cataracts (100% penetrance) resulting from an efficient impairment of lens fiber cell differentiation and coincident induction of cell proliferation. Lens tumors formed in 40% of adult mice from the mouse lineage with the highest level of E6 and E7 expression. Additionally, when lens cells from neonatal transgenic animals were placed in tissue culture, immortalized cell populations grew out and acquired a tumorigenic phenotype with continuous passage. These observations indicate that genetic changes in addition to the transgenes are likely necessary for tumor formation. These transgenic mice and cell lines provide the basis for further studies into the mechanism of action of E6 and E7 in eliciting the observed pathology and into the genetic alterations required for HPV-16-associated tumor progression. Images PMID:8382301

  2. Cell Cycle Regulatory Functions of the KSHV Oncoprotein LANA

    PubMed Central

    Wei, Fang; Gan, Jin; Wang, Chong; Zhu, Caixia; Cai, Qiliang

    2016-01-01

    Manipulation of cell cycle is a commonly employed strategy of viruses for achieving a favorable cellular environment during infection. Kaposi’s sarcoma-associated herpesvirus (KSHV), the primary etiological agent of several human malignancies including Kaposi’s sarcoma, and primary effusion lymphoma, encodes several oncoproteins that deregulate normal physiology of cell cycle machinery to persist with endothelial cells and B cells and subsequently establish a latent infection. During latency, only a small subset of viral proteins is expressed. Latency-associated nuclear antigen (LANA) is one of the latent antigens shown to be essential for transformation of endothelial cells in vitro. It has been well demonstrated that LANA is critical for the maintenance of latency, episome DNA replication, segregation and gene transcription. In this review, we summarize recent studies and address how LANA functions as an oncoprotein to steer host cell cycle-related events including proliferation and apoptosis by interacting with various cellular and viral factors, and highlight the potential therapeutic strategy of disrupting LANA-dependent signaling as targets in KSHV-associated cancers. PMID:27065950

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

    PubMed Central

    Fryrear, Kimberly A.; Guo, Xin

    2012-01-01

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

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

    PubMed

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

    2012-02-01

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

  5. TRIP-Br1 oncoprotein inhibits autophagy, apoptosis, and necroptosis under nutrient/serum-deprived condition

    PubMed Central

    Duan, Jingjing; Lee, Soonduck; Kim, Kyeri; Park, Yeonji; Yang, Young; Kim, Keun-Il; Lim, Jong-Seok; Cheon, Chung-Il; Kang, Young-Sook; Lee, Myeong-Sok

    2015-01-01

    TRIP-Br1 oncogenic protein has been shown to have multiple biological functions in cells. In this study, we demonstrate that TRIP-Br1 functions as an oncoprotein by inhibiting autophagy, apoptosis, and necroptosis of cancer cells and eventually helping them to survive under the nutrient/serum starved condition. TRIP-Br1 expression level was significantly increased in conditions with low levels of nutrients. Nutrient depleted conditions were induced by culturing cancer cells until they were overcrowded with high cell density or in media deprived of glucose, amino acids, or serum. Among them, serum starvation significantly enhanced the expression of TRIP-Br1 only in all tested breast cancer cell lines (MCF7, MDA-MB-231, T47D, MDA-MB-435, Hs578D, BT549, and MDA-MB-435) but not in the three normal cell lines (MCF10A, HfCH8, and NIH3T3). As compared with the control cells, the introduction of TRIP-Br1 silencing siRNA into MCF7 and MDA-MB-231 cells accelerated cell death by inducing apoptosis and necroptosis. In this process, TRIP-Br1 confers resistance to serum starvation-induced cell deaths by stabilizing the XIAP protein and inhibiting cellular ROS production. Moreover, our data also show that the intracellular increase of TRIP-Br1 protein resulting from serum starvation seems to occur in part through the blockage of PI3K/AKT signaling pathway. PMID:26334958

  6. MUC1 oncoprotein suppresses activation of the ARF-MDM2-p53 pathway.

    PubMed

    Raina, Deepak; Ahmad, Rehan; Chen, Dongshu; Kumar, Shailendra; Kharbanda, Surender; Kufe, Donald

    2008-12-01

    The MUC1 oncoprotein interacts with the c-Abl tyrosine kinase and blocks nuclear targeting of c-Abl in the apoptotic response to DNA damage. Mutation of the MUC1 cytoplasmic domain at Tyr-60 disrupts the MUC1-c-Abl interaction. The present results demonstrate that the MUC1(Y60F) mutant is a potent inducer of the ARF tumor suppressor. MUC1(Y60F) induces transcription of the ARF locus by a c-Abl-dependent mechanism that promotes CUL-4A-mediated nuclear export of the replication protein Cdc6. The functional significance of these findings is that MUC1(Y60F)-induced ARF expression and thereby inhibition of MDM2 results in the upregulation of p53 and the homeodomain interacting protein kinase 2 (HIPK2) serine/threonine kinase. HIPK2-mediated phosphorylation of p53 on Ser-46 was further associated with a shift from expression of the cell cycle arrest-related p21 gene to the apoptosis-related PUMA gene. We also show that the MUC1(Y60F) mutant functions as dominant negative inhibitor of tumorigenicity. These findings indicate that the oncogenic function of MUC1 is conferred by suppressing activation of the ARF-MDM2-p53 pathway. PMID:18981727

  7. Disruption of the G1/S Transition in Human Papillomavirus Type 16 E7-Expressing Human Cells Is Associated with Altered Regulation of Cyclin E

    PubMed Central

    Martin, Larry G.; Demers, G. William; Galloway, Denise A.

    1998-01-01

    The development of neoplasia frequently involves inactivation of the p53 and retinoblastoma (Rb) tumor suppressor pathways and disruption of cell cycle checkpoints that monitor the integrity of replication and cell division. The human papillomavirus type 16 (HPV-16) oncoproteins, E6 and E7, have been shown to bind p53 and Rb, respectively. To further delineate the mechanisms by which E6 and E7 affect cell cycle control, we examined various aspects of the cell cycle machinery. The low-risk HPV-6 E6 and E7 proteins did not cause any significant change in the levels of cell cycle proteins analyzed. HPV-16 E6 resulted in very low levels of p53 and p21 and globally elevated cyclin-dependent kinase (CDK) activity. In contrast, HPV-16 E7 had a profound effect on several aspects of the cell cycle machinery. A number of cyclins and CDKs were elevated, and despite the elevation of the levels of at least two CDK inhibitors, p21 and p16, CDK activity was globally increased. Most strikingly, cyclin E expression was deregulated both transcriptionally and posttranscriptionally and persisted at high levels in S and G2/M. Transit through G1 was shortened by the premature activation of cyclin E-associated kinase activity. Elevation of cyclin E levels required both the CR1 and CR2 domains of E7. These data suggest that cyclin E may be a critical target of HPV-16 E7 in the disruption of G1/S cell cycle progression and that the ability of E7 to regulate cyclin E involves activities in addition to the release of E2F. PMID:9444990

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

    PubMed Central

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

    2014-01-01

    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

  9. Clastogenic effect of the human T-cell leukemia virus type I Tax oncoprotein correlates with unstabilized DNA breaks.

    PubMed

    Majone, F; Jeang, K T

    2000-10-20

    Expression of the human T-cell leukemia virus type I (HTLV-I) Tax oncoprotein rapidly engenders DNA damage as reflected in a significant increase of micronuclei (MN) in cells. To understand better this phenomenon, we have investigated the DNA content of MN induced by Tax. Using an approach that we termed FISHI, fluorescent in situ hybridization and incorporation, we attempted to characterize MN with centric or acentric DNA fragments for the presence or absence of free 3'-OH ends. Free 3'-OH ends were defined as those ends accessible to in situ addition of digoxigenin-dUTP using terminal deoxynucleotidyl transferase. MN were also assessed for centromeric sequences using standard fluorescent in situ hybridization (FISH). Combining these results, we determined that Tax oncoprotein increased the frequency of MN containing centric DNA with free 3'-OH and decreased the frequency of MN containing DNA fragments that had incorporation-inaccessible 3'-ends. Recently, it has been suggested that intracellular DNA breaks without detectable 3'-OH ends are stabilized by the protective addition of telomeric caps, while breaks with freely detectable 3'-OH are uncapped and are labile to degradation, incomplete replication, and loss during cell division. Accordingly, based on increased detection of free 3'-OH-containing DNA fragments, we concluded that HTLV-I Tax interferes with protective cellular mechanism(s) used normally for stabilizing DNA breaks. PMID:10969065

  10. NUP98 fusion oncoproteins interact with the APC/C(Cdc20) as a pseudosubstrate and prevent mitotic checkpoint complex binding.

    PubMed

    Salsi, Valentina; Fantini, Sebastian; Zappavigna, Vincenzo

    2016-09-01

    NUP98 is a recurrent partner gene in translocations causing acute myeloid leukemias and myelodisplastic syndrome. The expression of NUP98 fusion oncoproteins has been shown to induce mitotic spindle defects and chromosome missegregation, which correlate with the capability of NUP98 fusions to cause mitotic checkpoint attenuation. We show that NUP98 oncoproteins physically interact with the APC/C(Cdc20) in the absence of the NUP98 partner protein RAE1, and prevent the binding of the mitotic checkpoint complex to the APC/C(Cdc20). NUP98 oncoproteins require the GLEBS-like domain present in their NUP98 moiety to bind the APC/C(Cdc20). We found that NUP98 wild-type is a substrate of APC/C(Cdc20) prior to mitotic entry, and that its binding to APC/C(Cdc20) is controlled via phosphorylation of a PEST sequence located within its C-terminal portion. We identify S606, within the PEST sequence, as a key target site, whose phosphorylation modulates the capability of NUP98 to interact with APC/C(Cdc20). We finally provide evidence for an involvement of the peptidyl-prolyl isomerase PIN1 in modulating the possible conformational changes within NUP98 that lead to its dissociation from the APC/C(Cdc20) during mitosis. Our results provide novel insight into the mechanisms underlying the aberrant capability of NUP98 oncoproteins to interact with APC/C(Cdc20) and to interfere with its function. PMID:27097363

  11. The Viral Oncoprotein LMP1 Exploits TRADD for Signaling by Masking Its Apoptotic Activity

    PubMed Central

    Schneider, Frank; Neugebauer, Julia; Griese, Janine; Liefold, Nicola; Kutz, Helmut; Briseño, Cinthia; Kieser, Arnd

    2008-01-01

    The tumor necrosis factor (TNF)-receptor 1–associated death domain protein (TRADD) mediates induction of apoptosis as well as activation of NF-κB by cellular TNF-receptor 1 (TNFR1). TRADD is also recruited by the latent membrane protein 1 (LMP1) oncoprotein of Epstein-Barr virus, but its role in LMP1 signaling has remained enigmatic. In human B lymphocytes, we have generated, to our knowledge, the first genetic knockout of TRADD to investigate TRADD's role in LMP1 signal transduction. Our data from TRADD-deficient cells demonstrate that TRADD is a critical signaling mediator of LMP1 that is required for LMP1 to recruit and activate I-κB kinase β (IKKβ). However, in contrast to TNFR1, LMP1-induced TRADD signaling does not induce apoptosis. Searching for the molecular basis for this observation, we characterized the 16 C-terminal amino acids of LMP1 as an autonomous and unique virus-derived TRADD-binding domain. Replacing the death domain of TNFR1 by LMP1′s TRADD-binding domain converts TNFR1 into a nonapoptotic receptor that activates NF-κB through a TRAF6-dependent pathway, like LMP1 but unlike wild-type TNFR1. Thus, the unique interaction of LMP1 with TRADD encodes the transforming phenotype of viral TRADD signaling and masks TRADD's pro-apoptotic function. PMID:18198944

  12. Therapeutic bispecific T-cell engager antibody targeting the intracellular oncoprotein WT1

    PubMed Central

    Dao, Tao; Pankov, Dmitry; Scott, Andrew; Korontsvit, Tatyana; Zakhaleva, Victoriya; Xu, Yiyang; Xiang, Jingyi; Yan, Su; de Morais Guerreiro, Manuel Direito; Veomett, Nicholas; Dubrovsky, Leonid; Curcio, Michael; Doubrovina, Ekaterina; Ponomarev, Vladimir; Liu, Cheng; O’Reilly, Richard J; Scheinberg, David A

    2015-01-01

    Intracellular tumor antigens presented on the cell surface in the context of human leukocyte antigen (HLA) molecules have been targeted by T cell–based therapies, but there has been little progress in developing small-molecule drugs or antibodies directed to these antigens. Here we describe a bispecific T-cell engager (BiTE) antibody derived from a T-cell receptor (TCR)-mimic monoclonal antibody (mAb) ESK1, which binds a peptide derived from the intracellular oncoprotein WT1 presented on HLA-A*02:01. Despite the very low density of the complexes at the cell surface, ESK1-BiTE selectively activated and induced proliferation of cytolytic human T cells that killed cells from multiple leukemias and solid tumors in vitro and in mice. We also discovered that in an autologous in vitro setting, ESK1-BiTE induced a robust secondary CD8 T-cell response specific for tumor-associated antigens other than WT1. Our study provides an approach that targets tumor-specific intracellular antigens without using cell therapy and suggests that epitope spreading could contribute to the therapeutic efficacy of this BiTE. PMID:26389576

  13. KIAA1324 Suppresses Gastric Cancer Progression by Inhibiting the Oncoprotein GRP78.

    PubMed

    Kang, Jin Muk; Park, Sujin; Kim, Staci Jakyong; Kim, Hyojung; Lee, Bona; Kim, Junil; Park, Jinah; Kim, Shin Tae; Yang, Han-Kwang; Kim, Woo Ho; Kim, Seong-Jin

    2015-08-01

    Recent advances in genome and transcriptome analysis have contributed to the identification of many potential cancer-related genes. Furthermore, biological and clinical investigations of the candidate genes provide us with a better understanding of carcinogenesis and development of cancer treatment. Here, we report a novel role of KIAA1324 as a tumor suppressor in gastric cancer. We observed that KIAA1324 was downregulated in most gastric cancers from transcriptome sequencing data and found that histone deacetylase was involved in the suppression of KIAA1324. Low KIAA1324 levels were associated with poor prognosis in gastric cancer patients. In the xenograft model, KIAA1324 significantly reduced tumor formation of gastric cancer cells and decreased development of preformed tumors. KIAA1324 also suppressed proliferation, invasion, and drug resistance and induced apoptosis in gastric cancer cells. Through protein interaction analysis, we identified GRP78 (glucose-regulated protein 78 kDa) as a KIAA1324-binding partner. KIAA1324 blocked oncogenic activities of GRP78 by inhibiting GRP78-caspase-7 interaction and suppressing GRP78-mediated AKT activation, thereby inducing apoptosis. In conclusion, our study reveals a tumor suppressive role of KIAA1324 via inhibition of GRP78 oncoprotein activities and provides new insight into the diagnosis and treatment of gastric cancer. PMID:26045166

  14. 29 CFR 2584.8477(e)-7 - Effective date.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... promulgated by the Board appearing at title 5, CFR, chapter VI, §§ 1660.1 through 1660.5 will no longer be... 29 Labor 9 2011-07-01 2011-07-01 false Effective date. 2584.8477(e)-7 Section 2584.8477(e)-7 Labor... FOR THE ALLOCATION OF FIDUCIARY RESPONSIBILITY § 2584.8477(e)-7 Effective date. This section...

  15. 29 CFR 2584.8477(e)-7 - Effective date.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... promulgated by the Board appearing at title 5, CFR, chapter VI, §§ 1660.1 through 1660.5 will no longer be... 29 Labor 9 2010-07-01 2010-07-01 false Effective date. 2584.8477(e)-7 Section 2584.8477(e)-7 Labor... FOR THE ALLOCATION OF FIDUCIARY RESPONSIBILITY § 2584.8477(e)-7 Effective date. This section...

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

    PubMed Central

    Buitrago-Pérez, Águeda; Hachimi, Mariam; Dueñas, Marta; Lloveras, Belén; Santos, Almudena; Holguín, Almudena; Duarte, Blanca; Santiago, Juan Luis; Akgül, Baki; Rodríguez-Peralto, José L.; Storey, Alan; Ribas, Catalina; Larcher, Fernando; del Rio, Marcela; Paramio, Jesús M.; García-Escudero, Ramón

    2012-01-01

    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

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

    PubMed Central

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

    1998-01-01

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

  18. MUC1-C oncoprotein promotes FLT3 receptor activation in acute myeloid leukemia cells

    PubMed Central

    Liu, Suiyang; Yin, Li; Stroopinsky, Dina; Rajabi, Hasan; Puissant, Alexandre; Stegmaier, Kimberly; Avigan, David; Kharbanda, Surender; Kufe, Donald

    2014-01-01

    Blasts from approximately one-third of patients with acute myeloid leukemia (AML) harbor activating mutations in the FMS-like tyrosine kinase 3 (FLT3) receptor tyrosine kinase that confer a poor prognosis. The Mucin 1-C-terminal subunit (MUC1-C) oncoprotein is aberrantly expressed in AML blasts and stem cells; however, there is no known interaction between MUC1-C and FLT3. The present studies demonstrate that MUC1-C associates with wild-type and mutant FLT3 in AML cells. Targeting MUC1-C with the cell-penetrating peptide inhibitor GO-203 disrupts MUC1-C/FLT3 complexes and downregulates FLT3 activation. GO-203 treatment of AML cells was also associated with inhibition of the FLT3 downstream effectors AKT, extracellular signal-regulated kinase, and STAT5. The results further show that AML cells with FLT3-activating mutations and resistant to the FLT3 inhibitor midostaurin/PKC412 are sensitive to GO-203–induced growth arrest and death. Moreover, GO-203 increases sensitivity of mutant FLT3 AML cells to FLT3 inhibitor treatment. These results indicate that MUC1-C contributes to FLT3 activation in AML cells and that targeting MUC1-C inhibits the FLT3 signaling pathway. Our findings support the development of MUC1-C inhibitors alone and in combination with agents that target FLT3 for the treatment of wild-type and mutant FLT3 AML. PMID:24282218

  19. LMO2 Oncoprotein Stability in T-Cell Leukemia Requires Direct LDB1 Binding

    PubMed Central

    Layer, Justin H.; Alford, Catherine E.; McDonald, W. Hayes

    2015-01-01

    LMO2 is a component of multisubunit DNA-binding transcription factor complexes that regulate gene expression in hematopoietic stem and progenitor cell development. Enforced expression of LMO2 causes leukemia by inducing hematopoietic stem cell-like features in T-cell progenitor cells, but the biochemical mechanisms of LMO2 function have not been fully elucidated. In this study, we systematically dissected the LMO2/LDB1-binding interface to investigate the role of this interaction in T-cell leukemia. Alanine scanning mutagenesis of the LIM interaction domain of LDB1 revealed a discrete motif, R320LITR, required for LMO2 binding. Most strikingly, coexpression of full-length, wild-type LDB1 increased LMO2 steady-state abundance, whereas coexpression of mutant proteins deficient in LMO2 binding compromised LMO2 stability. These mutant LDB1 proteins also exerted dominant negative effects on growth and transcription in diverse leukemic cell lines. Mass spectrometric analysis of LDB1 binding partners in leukemic lines supports the notion that LMO2/LDB1 function in leukemia occurs in the context of multisubunit complexes, which also protect the LMO2 oncoprotein from degradation. Collectively, these data suggest that the assembly of LMO2 into complexes, via direct LDB1 interaction, is a potential molecular target that could be exploited in LMO2-driven leukemias resistant to existing chemotherapy regimens. PMID:26598604

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

    PubMed

    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

    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 β-Catenin and Ha-ras oncoproteins in tumors of the two genotypes. PMID:24535843

  1. Interferon regulatory factor 7 is activated by a viral oncoprotein through RIP-dependent ubiquitination.

    PubMed

    Huye, Leslie E; Ning, Shunbin; Kelliher, Michelle; Pagano, Joseph S

    2007-04-01

    As a key mediator of type I interferon (IFN) (IFN-alpha/beta) responses, IFN regulatory factor 7 (IRF7) is essential to host immune defenses. Activation of IRF7 generally requires virus-induced C-terminal phosphorylation, which leads to its nuclear accumulation and activation of target genes. Here we use the Epstein-Barr virus (EBV) oncoprotein LMP1, which activates IRF7, to identify factors involved in IRF7 activation. We demonstrate for the first time that RIP activates IRF7 and that RIP and IRF7 interact under physiological conditions in EBV-positive Burkitt's lymphoma cells. We provide evidence that both RIP and IRF7 are ubiquitinated in these cells and that IRF7 preferentially interacts with ubiquitinated RIP. RIP is required for full activation of IRF7 by LMP1, with LMP1 stimulating the ubiquitination of RIP and its interaction with IRF7. Moreover, LMP1 stimulates RIP-dependent K63-linked ubiquitination of IRF7, which regulates protein function rather than proteasomal degradation of proteins. We suggest that RIP may serve as a general activator of IRF7, responding to and transmitting the signals from various stimuli, and that ubiquitination may be a general mechanism for enhancing the activity of IRF7. PMID:17296724

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

    PubMed

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

    2013-06-01

    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

  3. The HTLV-1 Tax oncoprotein represses Ku80 gene expression.

    PubMed

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

    2011-07-20

    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

  4. [Inactivation of failsafe programs by Twist oncoproteins and tumor progression].

    PubMed

    Puisieux, A

    2008-01-01

    Multicellular organisms have developed innate defense mechanisms to prevent the expansion of abnormal cells with significant proliferative potential. The two major safeguard mechanisms are premature senescence, which is characterized by definitive cell cycle arrest, and apoptosis, the most common form of programmed cell death. In normal and premalignant cells, the control of these processes is coupled to the regulation of cell proliferation, mainly through the p16 (Ink4A) -Rb and ARF-p53 intracellular signaling pathways. Hence, in benign tumors, aberrant mitogenic activity is counterbalanced by the induction of these oncosuppressive pathways, leading to either apoptosis or senescence which both limit tumor outgrowth. Progression towards malignant and potentially metastatic tumors requires the inhibition of these failsafe programs. Based on our work on Twist oncoproteins, we propose a presentation of recent data on cellular mechanisms by which cancer cells override the surveillance machinery and escape senescence and apoptosis, and we will describe the biological impact of this process on tumor metastasis. PMID:19061727

  5. Small-Molecule Inhibitors of the Myc Oncoprotein

    PubMed Central

    Fletcher, Steven; Prochownik, Edward V.

    2014-01-01

    The c-Myc (Myc) oncoprotein is among the most attractive of cancer targets given that is deregulated in the majority of tumors and that its inhibition profoundly affects their growth and/or survival. However, its role as a seldom-mutated transcription factor, its lack of enzymatic activity for which suitable pharmaceutical inhibitors could be crafted and its expression by normal cells have largely been responsible for its being viewed as “undruggable”. Work over the past several years, however, has begun to reverse this idea by allowing us to view Myc within the larger context of global gene regulatory control. Thus, Myc and its obligate heterodimeric partner, Max, are integral to the coordinated recruitment and post-translational modification of components of the core transcriptional machinery. Moreover, Myc over-expression re-programs numerous critical cellular functions and alters the cell’s susceptibility to their inhibition. This new knowledge has therefore served as a framework upon which to develop new pharmaceutical approaches. These include the continuing development of small molecules which act directly to inhibit the critical Myc-Max interaction, those which act indirectly to prevent Myc-directed post-translational modifications necessary to initiate productive transcription and those which inhibit vital pathways upon which the Myc-transformed cell is particularly reliant. PMID:24657798

  6. E7(7) on the light cone

    NASA Astrophysics Data System (ADS)

    Brink, Lars; Kim, Sung-Soo; Ramond, Pierre

    2008-06-01

    We use the Cremmer-Julia E7(7) non-linear symmetry of Script N = 8 Supergravity to derive its order κ2 on-shell Hamiltonian in terms of one chiral light-cone superfield. By requiring that E7(7) commute with the super-Poincaré group, we deduce to lowest non-trivial order in κ, the light cone E7(7) transformations of all fields of the theory, including the graviton. We then derive the dynamical supersymmetry transformation to order κ2, and express the Hamiltonian as a quadratic form in the chiral superfield.

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

    PubMed

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

    2012-01-01

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

  8. The human papillomavirus type 16 E7 gene product interacts with and trans-activates the AP1 family of transcription factors.

    PubMed Central

    Antinore, M J; Birrer, M J; Patel, D; Nader, L; McCance, D J

    1996-01-01

    The E7 gene product of human papillomavirus type 16 (HPV16) binds to the retinoblastoma gene product (pRb) and dissociates pRb-E2F complexes. However, the observation that the ability of E7 to bind pRb is not required for the HPV16-induced immortalization of primary keratinocytes prompted a search for other cellular factors bound by E7. Using a glutathione-S-transferase (GST) fusion protein system, we show that E7 complexes with AP1 transcription factors including c-Jun, JunB, JunD and c-Fos. The ability of E7 to complex with c-Jun in vivo is demonstrated by co-immunoprecipitation and the yeast two-hybrid system. An analysis of E7 point mutants in the GST system indicates that the E7 zinc-finger motif, but not the pRb binding domain, is involved in these interactions. Using c-Jun deletion mutants, E7 binding maps between amino acids 224 and 286 of c-Jun. E7 trans-activates c-Jun-induced transcription from a Jun responsive promoter, and this activity correlates with the ability of E7 mutants to bind Jun proteins. Finally, a transcriptionally inactive c-Jun deletion, which can bind E7, interferes with the E7-induced transformation of rat embryo fibroblasts in cooperation with an activated ras, indicating that the Jun-E7 interaction is physiologically relevant and that Jun factors may be targeted in the E7 transformation pathway. Images PMID:8617242

  9. Unique potential of 4-1BB agonist antibody to promote durable regression of HPV+ tumors when combined with an E6/E7 peptide vaccine

    PubMed Central

    Bartkowiak, Todd; Singh, Shailbala; Yang, Guojun; Galvan, Gloria; Haria, Dhwani; Ai, Midan; Allison, James P.; Sastry, K. Jagannadha; Curran, Michael A.

    2015-01-01

    Antibody modulation of T-cell coinhibitory (e.g., CTLA-4) or costimulatory (e.g., 4-1BB) receptors promotes clinical responses to a variety of cancers. Therapeutic cancer vaccination, in contrast, has produced limited clinical benefit and no curative therapies. The E6 and E7 oncoproteins of human papilloma virus (HPV) drive the majority of genital cancers, and many oropharyngeal tumors. We discovered 15–19 amino acid peptides from HPV-16 E6/E7 for which induction of T-cell immunity correlates with disease-free survival in patients treated for high-grade cervical neoplasia. We report here that intranasal vaccination with these peptides and the adjuvant alpha-galactosylceramide elicits systemic and mucosal T-cell responses leading to reduced HPV+ TC-1 tumor growth and prolonged survival in mice. We hypothesized that the inability of these T cells to fully reject established tumors resulted from suppression in the tumor microenvironment which could be ameliorated through checkpoint modulation. Combining this E6/E7 peptide vaccine with checkpoint blockade produced only modest benefit; however, coadministration with a 4-1BB agonist antibody promoted durable regression of established genital TC-1 tumors. Relative to other therapies tested, this combination of vaccine and α4-1BB promoted the highest CD8+ versus regulatory FoxP3+ T-cell ratios, elicited 2- to 5-fold higher infiltration by E7-specific CTL, and evoked higher densities of highly cytotoxic TcEO (T cytotoxic Eomesodermin) CD8 (>70-fold) and ThEO (T helper Eomesodermin) CD4 (>17-fold) T cells. These findings have immediate clinical relevance both in terms of the direct clinical utility of the vaccine studied and in illustrating the potential of 4-1BB antibody to convert therapeutic E6/E7 vaccines already in clinical trials into curative therapies. PMID:26351680

  10. The oncoprotein HBXIP promotes glucose metabolism reprogramming via downregulating SCO2 and PDHA1 in breast cancer

    PubMed Central

    You, Xiaona; Liu, Yunxia; Li, Yinghui; Wang, Zhen; Wang, Yue

    2015-01-01

    The glucose metabolism reprogramming is a hallmark of cancer. The oncoprotein hepatitis B X-interacting protein (HBXIP) functions in the development of breast cancer. In this study, we supposed that HBXIP might be involved in the glucose metabolism reprogramming in breast cancer. We showed that HBXIP led to increases in generation of intracellular glucose and lactate, as well as decreases in generation of reactive oxygen species. Expression of synthesis of cytochrome c oxidase 2 (SCO2) and pyruvate dehydrogenase alpha 1 (PDHA1), two factors of metabolic switch from oxidative phosphorylation to aerobic glycolysis, was suppressed by HBXIP. In addition, miR-183/182 and miR-96 directly inhibited the expression of SCO2 and PDHA1 through targeting their mRNA coding sequences (CDSs), respectively. Interestingly, HBXIP elevated the miR-183/96/182 cluster expression through hypoxia-inducible factor 1α (HIF1α). The stability of HIF1α was enhanced by HBXIP through disassociating interaction of von Hippel-Lindau protein (pVHL) with HIF1α. Moreover, miR-183 increased the levels of HIF1α protein through directly targeting CDS of VHL mRNA, forming a feedback loop of HIF1α/miR-183/pVHL/HIF1α. In function, HBXIP-elevated miR-183/96/182 cluster enhanced the glucose metabolism reprogramming in vitro. HBXIP-triggered glucose metabolism reprogramming promoted the growth of breast cancer in vivo. Thus, we conclude that the oncoprotein HBXIP enhances glucose metabolism reprogramming through suppressing SCO2 and PDHA1 in breast cancer. PMID:26309161

  11. The Subcellular Localisation of the Human Papillomavirus (HPV) 16 E7 Protein in Cervical Cancer Cells and Its Perturbation by RNA Aptamers

    PubMed Central

    Cesur, Özlem; Nicol, Clare; Groves, Helen; Mankouri, Jamel; Blair, George Eric; Stonehouse, Nicola J.

    2015-01-01

    Human papillomavirus (HPV) is the most common viral infection of the reproductive tract, affecting both men and women. High-risk oncogenic types are responsible for almost 90% of anogenital and oropharyngeal cancers including cervical cancer. Some of the HPV “early” genes, particularly E6 and E7, are known to act as oncogenes that promote tumour growth and malignant transformation. Most notably, HPV-16 E7 interacts with the tumour suppressor protein pRb, promoting its degradation, leading to cell cycle dysregulation in infected cells. We have previously shown that an RNA aptamer (termed A2) selectively binds to HPV16 E7 and is able to induce apoptosis in HPV16-transformed cervical carcinoma cell lines (SiHa) through reduction of E7 levels. In this study, we investigated the effects of the A2 aptamer on E7 localisation in order to define its effects on E7 activity. We demonstrate for the first time that E7 localised to the plasma membrane. In addition, we show that A2 enhanced E7 localisation in the ER and that the A2-mediated reduction of E7 was not associated with proteasomal degradation. These data suggest that A2 perturbs normal E7 trafficking through promoting E7 ER retention. PMID:26131956

  12. ERG oncoprotein expression in prostate carcinoma patients of different ethnicities

    PubMed Central

    KELLY, GREGORY M.; KONG, YINK HEAY; DOBI, ALBERT; SRIVASTAVA, SHIV; SESTERHENN, ISABELL A.; PATHMANATHAN, RAJADURAI; TAN, HUI MENG; TAN, SHYH-HAN; CHEONG, SOK CHING

    2015-01-01

    Overexpression of the erythroblast transformation-specific-related gene (ERG) oncoprotein due to transmembrane protease, serine 2 (TMPRSS2)-ERG fusion, the most prevalent genomic alteration in prostate cancer (CaP), is more frequently observed among Caucasian patients compared to patients of African or Asian descent. To the best of our knowledge, this is the first study to investigate the prevalence of ERG alterations in a multiethnic cohort of CaP patients. A total of 191 formalin-fixed paraffin-embedded sections of transrectal ultrasound-guided prostate biopsy specimens, collected from 120 patients treated at the Sime Darby Medical Centre, Subang Jaya, Malaysia, were analyzed for ERG protein expression by immunohistochemistry using the anti-ERG monoclonal antibody 9FY as a surrogate for the detection of ERG fusion events. The overall frequency of ERG protein expression in the population evaluated in this study was 39.2%. Although seemingly similar to rates reported in other Asian communities, the expression of ERG was distinct amongst different ethnic groups (P=0.004). Malaysian Indian (MI) patients exhibited exceedingly high expression of ERG in their tumors, almost doubling that of Malaysian Chinese (MC) patients, whereas ERG expression was very low amongst Malay patients (12.5%). When collectively analyzing data, we observed a significant correlation between younger patients and higher ERG expression (P=0.04). The prevalence of ERG expression was significantly different amongst CaP patients of different ethnicities. The higher number of ERG-expressing tumors among MI patients suggested that the TMPRSS2-ERG fusion may be particularly important in the pathogenesis of CaP amongst this group of patients. Furthermore, the more frequent expression of ERG among the younger patients analyzed suggested an involvement of ERG in the early onset of CaP. The results of this study underline the value of using ERG status to better understand the differences in the etiology

  13. ERG oncoprotein expression in prostate carcinoma patients of different ethnicities.

    PubMed

    Kelly, Gregory M; Kong, Yink Heay; Dobi, Albert; Srivastava, Shiv; Sesterhenn, Isabell A; Pathmanathan, Rajadurai; Tan, Hui Meng; Tan, Shyh-Han; Cheong, Sok Ching

    2015-01-01

    Overexpression of the erythroblast transformation-specific-related gene (ERG) oncoprotein due to transmembrane protease, serine 2 (TMPRSS2)-ERG fusion, the most prevalent genomic alteration in prostate cancer (CaP), is more frequently observed among Caucasian patients compared to patients of African or Asian descent. To the best of our knowledge, this is the first study to investigate the prevalence of ERG alterations in a multiethnic cohort of CaP patients. A total of 191 formalin-fixed paraffin-embedded sections of transrectal ultrasound-guided prostate biopsy specimens, collected from 120 patients treated at the Sime Darby Medical Centre, Subang Jaya, Malaysia, were analyzed for ERG protein expression by immunohistochemistry using the anti-ERG monoclonal antibody 9FY as a surrogate for the detection of ERG fusion events. The overall frequency of ERG protein expression in the population evaluated in this study was 39.2%. Although seemingly similar to rates reported in other Asian communities, the expression of ERG was distinct amongst different ethnic groups (P=0.004). Malaysian Indian (MI) patients exhibited exceedingly high expression of ERG in their tumors, almost doubling that of Malaysian Chinese (MC) patients, whereas ERG expression was very low amongst Malay patients (12.5%). When collectively analyzing data, we observed a significant correlation between younger patients and higher ERG expression (P=0.04). The prevalence of ERG expression was significantly different amongst CaP patients of different ethnicities. The higher number of ERG-expressing tumors among MI patients suggested that the TMPRSS2-ERG fusion may be particularly important in the pathogenesis of CaP amongst this group of patients. Furthermore, the more frequent expression of ERG among the younger patients analyzed suggested an involvement of ERG in the early onset of CaP. The results of this study underline the value of using ERG status to better understand the differences in the etiology

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

    ERIC Educational Resources Information Center

    Szeberenyi, Jozsef

    2009-01-01

    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…

  15. Targeting the Two Oncogenic Functional Sites of the HPV E6 Oncoprotein with a High-Affinity Bivalent Ligand**

    PubMed Central

    Ramirez, Juan; Poirson, Juline; Foltz, Clémence; Chebaro, Yassmine; Schrapp, Maxime; Meyer, Amandine; Bonetta, Anaëlle; Forster, Anne; Jacob, Yves; Masson, Murielle; Deryckère, François; Travé, Gilles

    2015-01-01

    The E6 oncoproteins of high-risk mucosal (hrm) human papillomaviruses (HPVs) contain a pocket that captures LxxLL motifs and a C-terminal motif that recruits PDZ domains, with both functions being crucial for HPV-induced oncogenesis. A chimeric protein was built by fusing a PDZ domain and an LxxLL motif, both known to bind E6. NMR spectroscopy, calorimetry and a mammalian protein complementation assay converged to show that the resulting PDZ-LxxLL chimera is a bivalent nanomolar ligand of E6, while its separated PDZ and LxxLL components are only micromolar binders. The chimera binds to all of the hrm-HPV E6 proteins tested but not to low-risk mucosal or cutaneous HPV E6. Adenovirus-mediated expression of the chimera specifically induces the death of HPV-positive cells, concomitant with increased levels of the tumour suppressor P53, its transcriptional target p21, and the apoptosis marker cleaved caspase 3. The bifunctional PDZ-LxxLL chimera opens new perspectives for the diagnosis and treatment of HPV-induced cancers. PMID:26014966

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

    SciTech Connect

    Kong, Chen; Lange, Jeffrey J.; Samovski, Dmitri; Su, Xiong; Liu, Jialiu; Sundaresan, Sinju; Stahl, Philip D.

    2013-05-03

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

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

    SciTech Connect

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

    2009-04-25

    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.

  18. The levels of epithelial anchor proteins β-catenin and zona occludens-1 are altered by E7 of human papillomaviruses 5 and 8.

    PubMed

    Heuser, Sandra; Hufbauer, Martin; Marx, Benjamin; Tok, Ali; Majewski, Slawomir; Pfister, Herbert; Akgül, Baki

    2016-02-01

    Infection with viruses of the genus Betapapillomavirus, β-human papillomaviruses (β-HPV), is implicated in the development of non-melanoma skin cancer. This was first evidenced for HPV5 and HPV8 in patients with the skin disease epidermodysplasia verruciformis (EV). The relocalization of the junctional bridging proteins β-catenin and zona occludens-1 (ZO-1) from the adherens and tight junctions are common processes of the epithelial-mesenchymal transition (EMT) associated with tumour invasion. Here, we report that β-catenin and ZO-1 are strongly upregulated by the E7 oncoproteins of HPV5 and HPV8 in keratinocytes grown in organotypic skin cultures. Although the membrane-tethered form of β-catenin was elevated, no signs of β-catenin activity within the canonical Wnt signalling pathway could be detected. The upregulation of β-catenin and ZO-1 could also be confirmed in the skin of HPV8 transgenic mice as well as in cutaneous squamous cell carcinomas of EV patients. These data provide the first evidence that β-catenin and ZO-1 are direct targets of E7 of the oncogenic β-HPV types 5 and 8. The ability to deregulate these epithelial junction proteins may contribute to the oncogenic potential of these viruses in human skin. PMID:26645068

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

    PubMed Central

    Kong, Chen; Lange, Jeffrey J.; Samovski, Dmitri; Su, Xiong; Liu, Jialiu; Sundaresan, Sinju; Stahl, Philip D.

    2013-01-01

    Expression of the hominoid-specific oncoprotein TBC1D3 promotes enhanced cell growth and proliferation by increased activation of signal transduction through several growth factors. Recently we documented the role of CUL7 E3 ligase in growth factors-induced ubiquitination and degradation of TBC1D3. Here we expanded our study to discover additional molecular mechanisms that control TBC1D3 protein turnover. We report that TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. The expression of double palmitoylation mutant TBC1D3:C318/325S resulted in protein mislocalization and enhanced growth factors-induced TBC1D3 degradation. Moreover, ubiquitination of TBC1D3 via CUL7 E3 ligase complex was increased by mutating the palmitoylation sites, suggesting that depalmitoylation of TBC1D3 makes the protein more available for ubiquitination and degradation. The results reported here provide novel insights into the molecular mechanisms that govern TBC1D3 protein degradation. Dysregulation of these mechanisms in-vivo could potentially result in aberrant TBC1D3 expression and promote oncogenesis. PMID:23578663

  20. The human papillomavirus (HPV) E6 oncoproteins promotes nuclear localization of active caspase 8

    SciTech Connect

    Manzo-Merino, Joaquin; Lizano, Marcela

    2014-02-15

    The HPV-16 E6 and E6{sup ⁎} proteins have been shown previously to be capable of regulating caspase 8 activity. We now show that the capacity of E6 to interact with caspase 8 is common to diverse HPV types, being also seen with HPV-11 E6, HPV-18 E6 and HPV-18 E6{sup ⁎}. Unlike most E6-interacting partners, caspase 8 does not appear to be a major proteasomal target of E6, but instead E6 appears able to stimulate caspase 8 activation, without affecting the overall apoptotic activity. This would appear to be mediated in part by the ability of the HPV E6 oncoproteins to recruit active caspase 8 to the nucleus. - Highlights: • Multiple HPV E6 oncoproteins interact with the caspase 8 DED domain. • HPV E6 stimulates activation of caspase 8. • HPV E6 promotes nuclear accumulation of caspase 8.

  1. 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

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

    2014-01-01

    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

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

    PubMed Central

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

    1996-01-01

    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

  3. The Human Papillomavirus Type 16 E6 Oncoprotein Can Down-Regulate p53 Activity by Targeting the Transcriptional Coactivator CBP/p300

    PubMed Central

    Zimmermann, Holger; Degenkolbe, Roland; Bernard, Hans-Ulrich; O’Connor, Mark J.

    1999-01-01

    The transforming proteins of the small DNA tumor viruses, simian virus 40 (SV40), adenovirus, and human papillomavirus (HPV) target a number of identical cellular regulators whose functional abrogation is required for transformation. However, while both adenovirus E1A and SV40 large T transforming properties also depend on the targeting of the transcriptional coactivator CBP/p300, no such interaction has been described for the HPV oncoprotein E6 or E7. Here, we demonstrate that the HPV-16 E6 protein, previously shown to facilitate the degradation of p53 in a complex with E6-associated protein (E6AP), also targets CBP/p300 in an interaction involving the C-terminal zinc finger of E6 and CBP residues 1808 to 1826. Furthermore, this interaction is limited to E6 proteins of high-risk HPVs associated with cervical cancer that have the capacity to repress p53-dependent transcription. An HPV-16 E6 mutant (L50G) that binds CBP/p300, but not E6AP, is still capable of down-regulating p53 transcriptional activity. Thus, HPV E6 proteins possess two distinct mechanisms by which to abrogate p53 function: the repression of p53 transcriptional activity by targeting the p53 coactivator CBP/p300, and the removal of cellular p53 protein through the proteosome degradation pathway. PMID:10400710

  4. Amino-functionalized poly(l-lactide) lamellar single crystals as a valuable substrate for delivery of HPV16-E7 tumor antigen in vaccine development

    PubMed Central

    Di Bonito, Paola; Petrone, Linda; Casini, Gabriele; Francolini, Iolanda; Ammendolia, Maria Grazia; Accardi, Luisa; Piozzi, Antonella; D’Ilario, Lucio; Martinelli, Andrea

    2015-01-01

    Background Poly(l-lactide) (PLLA) is a biodegradable polymer currently used in many biomedical applications, including the production of resorbable surgical devices, porous scaffolds for tissue engineering, nanoparticles and microparticles for the controlled release of drugs or antigens. The surfaces of lamellar PLLA single crystals (PLLAsc) were provided with amino groups by reaction with a multifunctional amine and used to adsorb an Escherichia coli-produced human papillomavirus (HPV)16-E7 protein to evaluate its possible use in antigen delivery for vaccine development. Methods PLLA single crystals were made to react with tetraethylenepentamine to obtain amino-functionalized PLLA single crystals (APLLAsc). Pristine and amino-functionalized PLLAsc showed a two-dimensional microsized and one-dimensional nanosized lamellar morphology, with a lateral dimension of about 15–20 μm, a thickness of about 12 nm, and a surface specific area of about 130 m2/g. Both particles were characterized and loaded with HPV16-E7 before being administered to C57BL/6 mice for immunogenicity studies. The E7-specific humoral-mediated and cell-mediated immune response as well as tumor protective immunity were analyzed in mice challenged with TC-1 cancer cells. Results Pristine and amino-functionalized PLLAsc adsorbed similar amounts of E7 protein, but in protein-release experiments E7-PLLAsc released a higher amount of protein than E7-APLLAsc. When the complexes were dried for observation by scanning electron microscopy, both samples showed a compact layer, but E7-APLLAsc showed greater roughness than E7-PLLAsc. Immunization experiments in mice showed that E7-APLLAsc induced a stronger E7-specific immune response when compared with E7-PLLAsc. Immunoglobulin G isotyping and interferon gamma analysis suggested a mixed Th1/Th2 immune response in both E7-PLLAsc-immunized and E7-APLLAsc-immunized mice. However, only the mice receiving E7-APLLAsc were fully protected from TC-1 tumor growth

  5. Eradication of B-ALL using chimeric antigen receptor-expressing T cells targeting the TSLPR oncoprotein.

    PubMed

    Qin, Haiying; Cho, Monica; Haso, Waleed; Zhang, Ling; Tasian, Sarah K; Oo, Htoo Zarni; Negri, Gian Luca; Lin, Yongshun; Zou, Jizhong; Mallon, Barbara S; Maude, Shannon; Teachey, David T; Barrett, David M; Orentas, Rimas J; Daugaard, Mads; Sorensen, Poul H B; Grupp, Stephan A; Fry, Terry J

    2015-07-30

    Adoptive transfer of T cells genetically modified to express chimeric antigen receptors (CARs) targeting the CD19 B cell-associated protein have demonstrated potent activity against relapsed/refractory B-lineage acute lymphoblastic leukemia (B-ALL). Not all patients respond, and CD19-negative relapses have been observed. Overexpression of the thymic stromal lymphopoietin receptor (TSLPR; encoded by CRLF2) occurs in a subset of adults and children with B-ALL and confers a high risk of relapse. Recent data suggest the TSLPR signaling axis is functionally important, suggesting that TSLPR would be an ideal immunotherapeutic target. We constructed short and long CARs targeting TSLPR and tested efficacy against CRLF2-overexpressing B-ALL. Both CARs demonstrated activity in vitro, but only short TSLPR CAR T cells mediated leukemia regression. In vivo activity of the short CAR was also associated with long-term persistence of CAR-expressing T cells. Short TSLPR CAR treatment of mice engrafted with a TSLPR-expressing ALL cell line induced leukemia cytotoxicity with efficacy comparable with that of CD19 CAR T cells. Short TSLPR CAR T cells also eradicated leukemia in 4 xenograft models of human CRLF2-overexpressing ALL. Finally, TSLPR has limited surface expression on normal tissues. TSLPR-targeted CAR T cells thus represent a potent oncoprotein-targeted immunotherapy for high-risk ALL. PMID:26041741

  6. Genomic instability driven by the human T-cell leukemia virus type I (HTLV-I) oncoprotein, Tax.

    PubMed

    Lemoine, Francene J; Marriott, Susan J

    2002-10-17

    The importance of maintaining genomic stability is evidenced by the fact that transformed cells often contain a variety of chromosomal abnormalities such as euploidy, translocations, and inversions. Gene amplification is a well-characterized hallmark of genomic instability thought to result from recombination events following the formation of double-strand, chromosomal breaks. Therefore, gene amplification frequency serves as an indicator of genomic stability. The PALA assay is designed to measure directly the frequency with which a specific gene, CAD, is amplified within a cell's genome. We have used the PALA assay to analyse the effects of the human T-cell leukemia virus type I (HTLV-I) oncoprotein, Tax, on genomic amplification. We demonstrate that Tax-expressing cells are five-times more likely to undergo gene amplification than control cells. Additionally, we show that Tax alters the ability of cells to undergo the typical PALA-mediated G(1) phase cell cycle arrest, thereby allowing cells to replicate DNA in the absence of appropriate nucleotide pools. This effect is likely the mechanism by which Tax induces gene amplification. These data suggest that HTLV-I Tax alters the genomic stability of cells, an effect that may play an important role in Tax-mediated, HTLV-I associated cellular transformation. PMID:12370813

  7. Eradication of B-ALL using chimeric antigen receptor–expressing T cells targeting the TSLPR oncoprotein

    PubMed Central

    Qin, Haiying; Cho, Monica; Haso, Waleed; Zhang, Ling; Tasian, Sarah K.; Oo, Htoo Zarni; Negri, Gian Luca; Lin, Yongshun; Zou, Jizhong; Mallon, Barbara S.; Maude, Shannon; Teachey, David T.; Barrett, David M.; Orentas, Rimas J.; Daugaard, Mads; Sorensen, Poul H. B.; Grupp, Stephan A.

    2015-01-01

    Adoptive transfer of T cells genetically modified to express chimeric antigen receptors (CARs) targeting the CD19 B cell–associated protein have demonstrated potent activity against relapsed/refractory B-lineage acute lymphoblastic leukemia (B-ALL). Not all patients respond, and CD19-negative relapses have been observed. Overexpression of the thymic stromal lymphopoietin receptor (TSLPR; encoded by CRLF2) occurs in a subset of adults and children with B-ALL and confers a high risk of relapse. Recent data suggest the TSLPR signaling axis is functionally important, suggesting that TSLPR would be an ideal immunotherapeutic target. We constructed short and long CARs targeting TSLPR and tested efficacy against CRLF2-overexpressing B-ALL. Both CARs demonstrated activity in vitro, but only short TSLPR CAR T cells mediated leukemia regression. In vivo activity of the short CAR was also associated with long-term persistence of CAR-expressing T cells. Short TSLPR CAR treatment of mice engrafted with a TSLPR-expressing ALL cell line induced leukemia cytotoxicity with efficacy comparable with that of CD19 CAR T cells. Short TSLPR CAR T cells also eradicated leukemia in 4 xenograft models of human CRLF2-overexpressing ALL. Finally, TSLPR has limited surface expression on normal tissues. TSLPR-targeted CAR T cells thus represent a potent oncoprotein-targeted immunotherapy for high-risk ALL. PMID:26041741

  8. Repression of the integrated papillomavirus E6/E7 promoter is required for growth suppression of cervical cancer cells.

    PubMed

    Francis, D A; Schmid, S I; Howley, P M

    2000-03-01

    The human papillomavirus (HPV) E2 protein is an important regulator of viral E6 and E7 gene expression. E2 can repress the viral promoter for E6 and E7 expression as well as block progression of the cell cycle in cancer cells harboring the DNA of "high-risk" HPV types. Although the phenomenon of E2-mediated growth arrest of HeLa cells and other HPV-positive cancer cells has been well documented, the specific mechanism by which E2 affects cellular proliferation has not yet been elucidated. Here, we show that bovine papillomavirus (BPV) E2-induced growth arrest of HeLa cells requires the repression of the E6 and E7 promoter. This repression is specific for E2TA and not E2TR, a BPV E2 variant that lacks the N-terminal transactivation domain. We demonstrate that expression of HPV16 E6 and E7 from a heterologous promoter that is not regulated by E2 rescues HeLa cells from E2-mediated growth arrest. Our data indicate that the pathway of E2-mediated growth arrest of HeLa cells requires repression of E6 and E7 expression through an activity specified by the transactivation domain of E2TA. PMID:10684283

  9. A Drosophila Model of HPV E6-Induced Malignancy Reveals Essential Roles for Magi and the Insulin Receptor

    PubMed Central

    Padash Barmchi, Mojgan; Gilbert, Mary; Thomas, Miranda; Banks, Lawrence; Zhang, Bing; Auld, Vanessa J.

    2016-01-01

    Cervical cancer is one of the leading causes of cancer death in women worldwide. The causative agents of cervical cancers, high-risk human papillomaviruses (HPVs), cause cancer through the action of two oncoproteins, E6 and E7. The E6 oncoprotein cooperates with an E3 ubiquitin ligase (UBE3A) to target the p53 tumour suppressor and important polarity and junctional PDZ proteins for proteasomal degradation, activities that are believed to contribute towards malignancy. However, the causative link between degradation of PDZ proteins and E6-mediated malignancy is largely unknown. We have developed an in vivo model of HPV E6-mediated cellular transformation using the genetic model organism, Drosophila melanogaster. Co-expression of E6 and human UBE3A in wing and eye epithelia results in severe morphological abnormalities. Furthermore, E6, via its PDZ-binding motif and in cooperation with UBE3A, targets a suite of PDZ proteins that are conserved in human and Drosophila, including Magi, Dlg and Scribble. Similar to human epithelia, Drosophila Magi is a major degradation target. Magi overexpression rescues the cellular abnormalities caused by E6+UBE3A coexpression and this activity of Magi is PDZ domain-dependent. Drosophila p53 was not targeted by E6+UBE3A, and E6+UBE3A activity alone is not sufficient to induce tumorigenesis, which only occurs when E6+UBE3A are expressed in conjunction with activated/oncogenic forms of Ras or Notch. Finally, through a genetic screen we have identified the insulin receptor signaling pathway as being required for E6+UBE3A induced hyperplasia. Our results suggest a highly conserved mechanism of HPV E6 mediated cellular transformation, and establish a powerful genetic model to identify and understand the cellular mechanisms that underlie HPV E6-induced malignancy. PMID:27537218

  10. A Drosophila Model of HPV E6-Induced Malignancy Reveals Essential Roles for Magi and the Insulin Receptor.

    PubMed

    Padash Barmchi, Mojgan; Gilbert, Mary; Thomas, Miranda; Banks, Lawrence; Zhang, Bing; Auld, Vanessa J

    2016-08-01

    Cervical cancer is one of the leading causes of cancer death in women worldwide. The causative agents of cervical cancers, high-risk human papillomaviruses (HPVs), cause cancer through the action of two oncoproteins, E6 and E7. The E6 oncoprotein cooperates with an E3 ubiquitin ligase (UBE3A) to target the p53 tumour suppressor and important polarity and junctional PDZ proteins for proteasomal degradation, activities that are believed to contribute towards malignancy. However, the causative link between degradation of PDZ proteins and E6-mediated malignancy is largely unknown. We have developed an in vivo model of HPV E6-mediated cellular transformation using the genetic model organism, Drosophila melanogaster. Co-expression of E6 and human UBE3A in wing and eye epithelia results in severe morphological abnormalities. Furthermore, E6, via its PDZ-binding motif and in cooperation with UBE3A, targets a suite of PDZ proteins that are conserved in human and Drosophila, including Magi, Dlg and Scribble. Similar to human epithelia, Drosophila Magi is a major degradation target. Magi overexpression rescues the cellular abnormalities caused by E6+UBE3A coexpression and this activity of Magi is PDZ domain-dependent. Drosophila p53 was not targeted by E6+UBE3A, and E6+UBE3A activity alone is not sufficient to induce tumorigenesis, which only occurs when E6+UBE3A are expressed in conjunction with activated/oncogenic forms of Ras or Notch. Finally, through a genetic screen we have identified the insulin receptor signaling pathway as being required for E6+UBE3A induced hyperplasia. Our results suggest a highly conserved mechanism of HPV E6 mediated cellular transformation, and establish a powerful genetic model to identify and understand the cellular mechanisms that underlie HPV E6-induced malignancy. PMID:27537218

  11. Expression and In Silico Analysis of the Recombinant Bovine Papillomavirus E6 Protein as a Model for Viral Oncoproteins Studies

    PubMed Central

    Mazzuchelli-de-Souza, J.; Carvalho, R. F.; Ruiz, R. M.; Melo, T. C.; Araldi, R. P.; Carvalho, E.; Thompson, C. E.; Sircili, M. P.; Beçak, W.; Stocco, R. C.

    2013-01-01

    Bovine papillomaviruses (BPVs) are recognized as the causal agents of economical relevant diseases in cattle, associated with the development of tumors in skin and mucosa. The oncogenesis process is mainly associated with different viral oncoprotein expressions, which are involved in cell transformation. The expression and characterization of recombinant viral oncoproteins represent an attractive strategy to obtain biotechnological products as antibodies and potential vaccines, Thus, the aim of this work was to clone and express the BPV-1 and BPV-2 E6 recombinant proteins and perform in silico analysis in order to develop a strategy for the systematic study of other papillomaviruses oncoproteins. The results demonstrated that BPV-1 and BPV-2 E6 recombinant proteins were expressed and purified from bacterial system as well as its in silico analysis was performed in order to explore and predict biological characteristics of these proteins. PMID:23878806

  12. Role of ubiquitin and the HPV E6 oncoprotein in E6AP-mediated ubiquitination

    PubMed Central

    Mortensen, Franziska; Schneider, Daniel; Barbic, Tanja; Sladewska-Marquardt, Anna; Kühnle, Simone; Marx, Andreas; Scheffner, Martin

    2015-01-01

    Deregulation of the ubiquitin ligase E6 associated protein (E6AP) encoded by the UBE3A gene has been associated with three different clinical pictures. Hijacking of E6AP by the E6 oncoprotein of distinct human papillomaviruses (HPV) contributes to the development of cervical cancer, whereas loss of E6AP expression or function is the cause of Angelman syndrome, a neurodevelopmental disorder, and increased expression of E6AP has been involved in autism spectrum disorders. Although these observations indicate that the activity of E6AP has to be tightly controlled, only little is known about how E6AP is regulated at the posttranslational level. Here, we provide evidence that the hydrophobic patch of ubiquitin comprising Leu-8 and Ile-44 is important for E6AP-mediated ubiquitination, whereas it does not affect the catalytic properties of the isolated catalytic HECT domain of E6AP. Furthermore, we show that the HPV E6 oncoprotein rescues the disability of full-length E6AP to use a respective hydrophobic patch mutant of ubiquitin for ubiquitination and that it stimulates E6AP-mediated ubiquitination of Ring1B, a known substrate of E6AP, in vitro and in cells. Based on these data, we propose that E6AP exists in at least two different states, an active and a less active or latent one, and that the activity of E6AP is controlled by noncovalent interactions with ubiquitin and allosteric activators such as the HPV E6 oncoprotein. PMID:26216987

  13. Intracellular Analysis of the Interaction between the Human Papillomavirus Type 16 E6 Oncoprotein and Inhibitory Peptides.

    PubMed

    Stutz, Christina; Reinz, Eileen; Honegger, Anja; Bulkescher, Julia; Schweizer, Johannes; Zanier, Katia; Travé, Gilles; Lohrey, Claudia; Hoppe-Seyler, Karin; Hoppe-Seyler, Felix

    2015-01-01

    Oncogenic types of human papillomaviruses (HPVs) cause cervical cancer and other malignancies in humans. The HPV E6 oncoprotein is considered to be an attractive therapeutic target since its inhibition can lead to the apoptotic cell death of HPV-positive cancer cells. The HPV type 16 (HPV16) E6-binding peptide pep11, and variants thereof, induce cell death specifically in HPV16-positive cancer cells. Although they do not encompass the LxxLL binding motif found in cellular HPV16 E6 interaction partners, such as E6AP, the pep11 variants strongly bind to HPV16 E6 by contacting the recently identified E6AP binding pocket. Thus, these peptides can serve as prototype E6-inhibitory molecules which target the E6AP pocket. We here analyzed their intracellular interaction with HPV16 E6. By comprehensive intracellular binding studies and GST pull-down assays, we show that E6-binding competent pep11 variants induce the formation of a trimeric complex, consisting of pep11, HPV16 E6 and p53. These findings indicate that peptides, which do not contain the LxxLL motif, can reshape E6 to enable its interaction with p53. The formation of the trimeric HPV16 E6 / peptide / p53 complex was associated with an increase of endogenous HPV16 E6 protein amounts. Yet, total cellular p53 amounts were also increased, indicating that the E6 / E6AP-mediated degradation of p53 is blocked. These findings suggest that inhibition of oncogenic activities by targeting the E6AP pocket on HPV16 E6 could be a strategy for therapeutic intervention. PMID:26151636

  14. Alternative splicing and caspase-mediated cleavage generate antagonistic variants of the stress oncoprotein LEDGF/p75.

    PubMed

    Brown-Bryan, Terry A; Leoh, Lai S; Ganapathy, Vidya; Pacheco, Fabio J; Mediavilla-Varela, Melanie; Filippova, Maria; Linkhart, Thomas A; Gijsbers, Rik; Debyser, Zeger; Casiano, Carlos A

    2008-08-01

    There is increasing evidence that an augmented state of cellular oxidative stress modulates the expression of stress genes implicated in diseases associated with health disparities such as certain cancers and diabetes. Lens epithelium-derived growth factor p75 (LEDGF/p75), also known as DFS70 autoantigen, is emerging as a survival oncoprotein that promotes resistance to oxidative stress-induced cell death and chemotherapy. We previously showed that LEDGF/p75 is targeted by autoantibodies in prostate cancer patients and is overexpressed in prostate tumors, and that its stress survival activity is abrogated during apoptosis. LEDGF/p75 has a COOH-terminally truncated splice variant, p52, whose role in stress survival and apoptosis has not been thoroughly investigated. We observed unbalanced expression of these proteins in a panel of tumor cell lines, with LEDGF/p75 generally expressed at higher levels. During apoptosis, caspase-3 cleaved p52 to generate a p38 fragment that lacked the NH(2)-terminal PWWP domain and failed to transactivate the Hsp27 promoter in reporter assays. However, p38 retained chromatin association properties and repressed the transactivation potential of LEDGF/p75. Overexpression of p52 or its variants with truncated PWWP domains in several tumor cell lines induced apoptosis, an activity that was linked to the presence of an intron-derived COOH-terminal sequence. These results implicate the PWWP domain of p52 in transcription function but not in chromatin association and proapoptotic activities. Consistent with their unbalanced expression in tumor cells, LEDGF/p75 and p52 seem to play antagonistic roles in the cellular stress response and could serve as targets for novel antitumor therapies. PMID:18708362

  15. Role of dual specificity tyrosine-phosphorylation-regulated kinase 1B (Dyrk1B) in S-phase entry of HPV E7 expressing cells from quiescence

    PubMed Central

    Zhou, Na; Yuan, Shoudao; Wang, Rongchun; Zhang, Weifang; Chen, Jason J.

    2015-01-01

    The high-risk human papillomavirus (HPV) is the causative agent for cervical cancer. The HPV E7 oncogene promotes S-phase entry from quiescent state in the presence of elevated cell cycle inhibitor p27Kip1, a function that may contribute to carcinogenesis. However, the mechanism by which HPV E7 induces quiescent cells to entry into S-phase is not fully understood. Interestingly, we found that Dyrk1B, a dual-specificity kinase and negative regulator of cell proliferation in quiescent cells, was upregulated in E7 expressing cells. Surprisingly and in contrast to what was previously reported, Dyrk1B played a positive role in S-phase entry of quiescent HPV E7 expressing cells. Mechanistically, Dyrk1B contributed to p27 phosphorylation (at serine 10 and threonine 198), which was important for the proliferation of HPV E7 expressing cells. Moreover, Dyrk1B up-regulated HPV E7. Taken together, our studies uncovered a novel function of Dyrk1B in high-risk HPV E7-mediated cell proliferation. Dyrk1B may serve as a target for therapy in HPV-associated cancers. PMID:26307683

  16. Eradication of large tumors expressing human papillomavirus E7 protein by therapeutic vaccination with E7 fused to the extra domain a from fibronectin.

    PubMed

    Mansilla, Cristina; Berraondo, Pedro; Durantez, Maika; Martínez, Marta; Casares, Noelia; Arribillaga, Laura; Rudilla, Francesc; Fioravanti, Jessica; Lozano, Teresa; Villanueva, Lorea; Sarobe, Pablo; Borrás, Francisco; Leclerc, Claude; Prieto, Jesús; Lasarte, Juan José

    2012-08-01

    Cervical carcinoma is one of the most common cancers in women worldwide. It is well established that chronic infection of the genital tract by various mucosatropic human papillomavirus (HPV) types causes cervical cancer. Cellular immunity to E7 protein from HPV (HPVE7) has been associated with clinical and cytologic resolution of HPV-induced lesions. Thus, we decided to test if targeting of HPVE7 to dendritic cells using a fusion protein containing the extra domain A (EDA) from fibronectin, a natural ligand for TLR4, and HPVE7 (EDA-HPVE7) might be an efficient vaccine for the treatment of cervical carcinoma. We found that EDA-HPVE7 fusion protein was efficiently captured by bone marrow derived dendritic cells in vitro and induced their maturation, with the upregulation of maturation markers and the production of IL-12. Immunization of mice with EDA-HPVE7 fusion protein induced antitumor CD8(+) T cell responses in the absence of additional adjuvants. Repeated intratumoral administration of EDA-HPVE7 in saline was able to cure established TC-1 tumors of 5-7 mm in diameter. More importantly, intravenous injection with EDA-HPVE7 in combination with the TLR ligand polyinosinic-polycytidylic acid (pIC), or with low doses of cyclophosphamide and the TLR9 ligand CpG-B complexed in cationic lipids, were able to eradicate large established TC-1 tumors (1.2 cm in diameter). Thus, therapeutic vaccination with EDA-HPVE7 fusion protein may be effective in the treatment of human cervical carcinoma. PMID:21898393

  17. Acetylation of the c-MYC oncoprotein is required for cooperation with the HTLV-1 p30II accessory protein and the induction of oncogenic cellular transformation by p30II/c-MYC

    PubMed Central

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

    2014-01-01

    The human T-cell leukemia retrovirus type-1 (HTLV-1) p30II protein is a multifunctional latency-maintenance factor that negatively regulates viral gene expression and deregulates host signaling pathways involved in aberrant T-cell growth and proliferation. We have previously demonstrated that p30II interacts with the c-MYC oncoprotein and enhances c-MYC-dependent transcriptional and oncogenic functions. However, the molecular and biochemical events that mediate the cooperation between p30II and c-MYC remain to be completely understood. Herein we demonstrate that p30II induces lysine-acetylation of the c-MYC oncoprotein. Acetylation-defective c-MYC Lys→Arg substitution mutants are impaired for oncogenic transformation with p30II in c-myc−/− HO15.19 fibroblasts. Using dual-chromatin-immunoprecipitations (dual-ChIPs), we further demonstrate that p30II is present in c-MYC-containing nucleoprotein complexes in HTLV-1-transformed HuT-102 T-lymphocytes. Moreover, p30II inhibits apoptosis in proliferating cells expressing c-MYC under conditions of genotoxic stress. These findings suggest that c-MYC-acetylation is required for the cooperation between p30II/c-MYC which could promote proviral replication and contribute to HTLV-1-induced carcinogenesis. PMID:25569455

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

    PubMed Central

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

    2015-01-01

    Objective. To investigate the possible mechanisms of oxymatrine's role in anti laryngeal squamous cell carcinoma. Methods. We examined the effects of oxymatrine on the proliferation, cell cycle phase distribution, apoptosis, and the protein and mRNA expression levels of HPV16E7 gene in laryngeal carcinoma Hep-2 cells in vitro. The HPV16E7 siRNA inhibition was also done to confirm the effect of downregulating HPV16E7 on the proliferation in Hep-2 cells. Results. Oxymatrine significantly inhibited the growth and proliferation of Hep-2 cells in a dose-dependence and time-dependence manner. Oxymatrine blocked Hep-2 cells in G0/G1 phase, resulting in an obvious accumulation of G0/G1 phase cells while decreasing S phase cells. Oxymatrine induced apoptosis of Hep-2 cells, whose apoptotic rate amounted to about 42% after treatment with 7 mg/mL oxymatrine for 72 h. Oxymatrine also downregulated the expression of HPV16E7 gene, as determined by the western blotting and reverse transcription-polymerase chain reaction analysis. Knockdown of HPV16E7 effectively inhibited the proliferation of Hep-2 cells. Conclusions. Oxymatrine inhibits the proliferation and induces apoptosis of laryngeal carcinoma Hep-2 cells, which might be mediated by a significant cell cycle arrest in G0/G1 phase and downregulation of HPV16E7 gene. Oxymatrine is considered to be a likely preventive and curative candidate for laryngeal cancer. PMID:25811021

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

    PubMed Central

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

    2014-01-01

    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

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

    SciTech Connect

    Barrow-Laing, Lisa; Chen Wei; Roman, Ann

    2010-05-10

    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.

  1. Oncoprotein kinase

    DOEpatents

    Karin, Michael; Hibi, Masahiko; Lin, Anning

    2001-02-27

    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.

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

    PubMed Central

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

    2012-01-01

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

  3. MPG-based nanoparticle: An efficient delivery system for enhancing the potency of DNA vaccine expressing HPV16E7.

    PubMed

    Saleh, Tayebeh; Bolhassani, Azam; Shojaosadati, Seyed Abbas; Aghasadeghi, Mohammad Reza

    2015-06-22

    DNA vaccines against human papillomavirus (HPV) type 16 have not been successful in clinical trials, due to the lack of an appropriate delivery system. In this study, a peptide-based gene delivery system, MPG, which forms stable non-covalent nanoparticles with nucleic acids, was used for in vitro and in vivo delivery of HPV16 E7 DNA as a model antigen. The results demonstrated that at Nitrogen/Phosphate (N/P) ratio over 10:1, this peptide can effectively condense plasmid DNA into stable nanoparticles with an average size of 180-210nm and a positive surface charge. The transfection efficiency of MPG-based nanoparticles was shown to be comparable with Polyethyleneimine (PEI). The efficient protein expression detected by western blotting and flow cytometry supports the potential of MPG-based nanoparticles as a potent delivery system in DNA vaccine formulations. Immunization with MPG/E7DNA nanoparticles at an N/P ratio of 10:1 induced a stronger Th1 cellular immune response with a predominant interferon-γ (IFN-γ) profile than those induced by E7DNA alone in a murine tumor model. These findings suggest that MPG peptide as a novel gene delivery system could have promising applications in improving HPV therapeutic vaccines. PMID:26001433

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  6. Deletion analysis of BMI1 oncoprotein identifies its negative regulatory domain

    PubMed Central

    2010-01-01

    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

  7. Natural variant of the Helicobacter pylori CagA oncoprotein that lost the ability to interact with PAR1.

    PubMed

    Hashi, Kana; Murata-Kamiya, Naoko; Varon, Christine; Mégraud, Francis; Dominguez-Bello, Maria Gloria; Hatakeyama, Masanori

    2014-03-01

    Helicobacter pylori strains carrying the cagA gene are associated with severe disease outcomes, most notably gastric cancer. CagA protein is delivered into gastric epithelial cells by a type IV secretion system. The translocated CagA undergoes tyrosine phosphorylation at the C-terminal EPIYA motifs by host cell kinases. Tyrosine-phosphorylated CagA acquires the ability to interact with and activate SHP2, thereby activating mitogenic signaling and inducing cell morphological transformation (hummingbird phenotype). CagA also interacts with PAR1b via the CM sequence, resulting in induction of junctional and polarity defects. Furthermore, CagA-PAR1b interaction stabilizes the CagA-SHP2 complex. Because transgenic mice systemically expressing CagA develop gastrointestinal and hematological malignancies, CagA is recognized as a bacterium-derived oncoprotein. Interestingly, the C-terminal region of CagA displays a large diversity among H. pylori strains, which influences the ability of CagA to bind to SHP2 and PAR1b. In the present study, we investigated the biological activity of v225d CagA, an Amerindian CagA of H. pylori isolated from a Venezuelan Piaroa Amerindian subject, because the variant CagA does not possess a canonical CM sequence. We found that v225d CagA interacts with SHP2 but not PAR1b. Furthermore, SHP2-binding activity of v225d CagA was much lower than that of CagA of H. pylori isolated from Western countries (Western CagA). v225d CagA also displayed a reduced ability to induce the hummingbird phenotype than that of Western CagA. Given that perturbation of PAR1b and SHP2 by CagA underlies the oncogenic potential of CagA, the v225d strain is considered to be less oncogenic than other well-studied cagA-positive H. pylori strains. PMID:24354359

  8. The Epstein-Barr virus encoded LMP1 oncoprotein modulates cell adhesion via regulation of activin A/TGFβ and β1 integrin signalling

    PubMed Central

    Morris, Mhairi A.; Dawson, Christopher W.; Laverick, Louise; Davis, Alexandra M.; Dudman, Joe P. R.; Raveenthiraraj, Sathuwarman; Ahmad, Zeeshan; Yap, Lee-Fah; Young, Lawrence S.

    2016-01-01

    Approximately 20% of global cancer incidence is causally linked to an infectious agent. Epstein-Barr virus (EBV) accounts for around 1% of all virus-associated cancers and is associated with nasopharyngeal carcinoma (NPC). Latent membrane protein 1 (LMP1), the major oncoprotein encoded by EBV, behaves as a constitutively active tumour necrosis factor (TNF) receptor activating a variety of signalling pathways, including the three classic MAPKs (ERK-MAPK, p38 MAPK and JNK/SAPK). The present study identifies novel signalling properties for this integral membrane protein via the induction and secretion of activin A and TGFβ1, which are both required for LMP1’s ability to induce the expression of the extracellular matrix protein, fibronectin. However, it is evident that LMP1 is unable to activate the classic Smad-dependent TGFβ signalling pathway, but rather elicits its effects through the non-Smad arm of TGFβ signalling. In addition, there is a requirement for JNK/SAPK signalling in LMP1-mediated fibronectin induction. LMP1 also induces the expression and activation of the major fibronectin receptor, α5β1 integrin, an effect that is accompanied by increased focal adhesion formation and turnover. Taken together, these findings support the putative role for LMP1 in the pathogenesis of NPC by contributing to the metastatic potential of epithelial cells. PMID:26782058

  9. A DNA vaccine encoding mutated HPV58 mE6E7-Fc-GPI fusion antigen and GM-CSF and B7.1

    PubMed Central

    Wang, He; Yu, Jiyun; Li, Li

    2015-01-01

    Background Persistent infection with high-risk human papillomavirus (HPV) is a predominant cause of cervical cancer, and HPV58 is the third most common virus detected in the patients with cervical cancer in Asia. E6 and E7 are the viral oncogenes which are constitutively expressed in HPV-associated tumor cells and can be used as target antigens for related immunotherapy. In this study, we modified the HPV58 E6 and E7 oncogenes to eliminate their oncogenic potential and constructed a recombinant DNA vaccine that coexpresses the sig-HPV58 mE6E7-Fc-GPI fusion antigen in addition to granulocyte-macrophage colony-stimulating factor (GM-CSF) and B7.1 as molecular adjuvants (PVAX1-HPV58 mE6E7FcGB) for the treatment of HPV58 (+) cancer. Methods PVAX1-HPV58 mE6E7FcGB recombinant DNA vaccine was constructed to express a fusion protein containing a signal peptide, a modified HPV58 mE6E7 gene, and human IgG Fc and glycosylphosphatidylinositol (GPI)-anchoring sequences using the modified DNA vaccine vector PVAX1-IRES-GM/B7.1 that coexpresses GM-CSF, and B7.1. C57BL/6 mice were challenged by HPV58 E6E7-expressing B16-HPV58 E6E7 cells, followed by immunization by PVAX1-HPV58 mE6E7FcGB vaccine on days 7, 14, 21 after tumor challenge. The cellular immune responses in immunized mice were assessed by measuring IFN-γ production in splenocytes upon stimulation by HPV58 E6E7-GST protein and the lysis of B16-HPV58 E6E7 target cells by splenocytes after restimulation with HPV58 E6E7-GST protein. The antitumor efficacy was evaluated by monitoring the growth of the tumor. Results PVAX1-HPV58 mE6E7FcGB elicited varying levels of IFN-lsgdB58onn T-cell immune responses and lysis of target cell in mice in response to the recombinant antigen HPV58 E6E7-GST. Furthermore, the vaccine also induced antitumor responses in the HPV58 (+) B16-HPV58 E6E7 tumor challenge model as evidenced by delayed tumor development. Conclusion The recombinant DNA vaccine PVAX1-HPV58 mE6E7FcGB efficiently generates

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

    PubMed Central

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

    2011-01-01

    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-λ, 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

  11. Transforming activity of a novel mutant of HPV16 E6E7 fusion gene.

    PubMed

    Xie, Qiang; Zhou, Zhi-Xiang; Li, Ze-Lin; Zeng, Yi

    2011-06-01

    An optimized recombinant HPV16 E6E7 fusion gene (HPV16 ofE6E7) was constructed according to codon usage for mammalian cell expression, and a mutant of HPV16 ofE6E7 fusion gene (HPV16 omfE6E7) was generated by site-directed mutagenesis at L57G, C113R for the E6 protein and C24G, E26G for the E7 protein for HPV16 ofE6E7 [patent pending (CN 101100672)]. The HPV16 omfE6E7 gene constructed in this work not only lost the transformation capability to NIH 3T3 cells and tumorigenicity in SCID mice, but also maintained very good stability and antigenicity. These results suggests that the HPV16 omfE6E7 gene should undergo further study for application as a safe antigen-specific therapeutic vaccine for HPV16-associated tumors. PMID:21667341

  12. In Silico Profiling of the Potentiality of Curcumin and Conventional Drugs for CagA Oncoprotein Inactivation.

    PubMed

    Srivastava, Akhileshwar K; Tewari, Mallika; Shukla, Hari S; Roy, Bijoy K

    2015-08-01

    The oncoprotein cytotoxic associated gene A (CagA) of Helicobacter pylori plays a pivotal role in the development of gastric cancer, so it has been an important target for anti-H. pylori drugs. Conventional drugs are currently being implemented against H. pylori. The inhibitory role of plant metabolites like curcumin against H. pylori is still a major scientific challenge. Curcumin may represent a novel promising drug against H. pylori infection without producing side effects. In the present study, a comparative analysis between curcumin and conventional drugs (clarithromycin, amoxicillin, pantoprazole, and metronidazole) was carried out using databases to investigate the potential of curcumin against H. pylori targeting the CagA oncoprotein. Curcumin was filtered using Lipinski's rule of five and the druglikeness property for evaluation of pharmacological properties. Subsequently, molecular docking was employed to determine the binding affinities of curcumin and conventional drugs to the CagA oncoprotein. According to the results obtained from FireDock, the binding energy of curcumin was higher than those of amoxicillin, pantoprazole, and metronidazole, except for clarithromycin, which had the highest binding energy. Accordingly, curcumin may become a promising lead compound against CagA+ H. pylori infection. PMID:25996140

  13. Hydrophobic Effect Drives Oxygen Uptake in Myoglobin via Histidine E7*

    PubMed Central

    Boechi, Leonardo; Arrar, Mehrnoosh; Martí, Marcelo A.; Olson, John S.; Roitberg, Adrián E.; Estrin, Darío A.

    2013-01-01

    Since the elucidation of the myoglobin (Mb) structure, a histidine residue on the E helix (His-E7) has been proposed to act as a gate with an open or closed conformation controlling access to the active site. Although it is believed that at low pH, the His-E7 gate is in its open conformation, the full relationship between the His-E7 protonation state, its conformation, and ligand migration in Mb is hotly debated. We used molecular dynamics simulations to first address the effect of His-E7 protonation on its conformation. We observed the expected shift from the closed to the open conformation upon protonation, but more importantly, noted a significant difference between the conformations of the two neutral histidine tautomers. We further computed free energy profiles for oxygen migration in each of the possible His-E7 states as well as in two instructive Mb mutants: Ala-E7 and Trp-E7. Our results show that even in the closed conformation, the His-E7 gate does not create a large barrier to oxygen migration and permits oxygen entry with only a small rotation of the imidazole side chain and movement of the E helix. We identify, instead, a hydrophobic site in the E7 channel that can accommodate an apolar diatomic ligand and enhances ligand uptake particularly in the open His-E7 conformation. This rate enhancement is diminished in the closed conformation. Taken together, our results provide a new conceptual framework for the histidine gate hypothesis. PMID:23297402

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

    PubMed Central

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

    2012-01-01

    Due to the strong relationship between the Human Papillomavirus (HPV) “high-risk” subtypes and cervical cancers, most HPV-related studies have been focusing on the “high-risk” HPV subtypes 16 and 18. However, it has been suggested that the “low-risk” subtypes of HPV, HPV6 and HPV11, are the major cause of recurrent respiratory papillomatosis and genital warts. In addition, HPV 6 and 11 are also associated with otolaryngologic malignancies, carcinoma of the lung, tonsil, larynx and low-grade cervical lesions. Therefore, development of HPV therapeutic vaccines targeting on subtypes 6 and 11 E6 or E7 are in great need. In this report, we describe two novel engineered DNA vaccines that encode HPV 6 and 11 consensus E6/E7 fusion proteins (p6E6E7 and p11E6E7) by utilizing a multi-phase strategy. Briefly, after generating consensus sequences, several modifications were performed to increase the expression of both constructs, including codon/RNA optimization, addition of a Kozak sequence and a highly efficient leader sequence. An endoproteolytic cleavage site was also introduced between E6 and E7 protein for proper protein folding and for better CTL processing. The expressions of both constructs were confirmed by western blot analysis and immunofluorescence assay. Vaccination with these DNA vaccines could elicit robust cellular immune responses. The epitope mapping assay was performed to further characterize the cellular immune responses induced by p6E6E7 and p11E6E7. The HPV 6 and 11 E6 or E7-specific immunodominant and subdominant epitopes were verified, respectively. The intracellular cytokine staining revealed that the magnitude of IFN-γ and TNF-α secretion in antigen-specific CD8+ cells was significantly enhanced, indicating that the immune responses elicited by p6E6E7 and p11E6E7 was heavily skewed toward driving CD8+ T cells. Such DNA immunogens are interesting candidates for further studies on HPV 6 and 11-associated diseases. PMID:22336879

  15. Suppression in vivo of human papillomavirus type 18 E6-E7 gene expression in nontumorigenic HeLa X fibroblast hybrid cells.

    PubMed Central

    Bosch, F X; Schwarz, E; Boukamp, P; Fusenig, N E; Bartsch, D; zur Hausen, H

    1990-01-01

    The E6 and E7 genes of the cancer-associated human papillomavirus (HPV) types 16 (HPV16) and 18 (HPV18) can induce cell immortalization in vitro in normal human keratinocytes. This, however, is not associated with tumorigenicity in vivo. On the other hand, tumorigenicity of HPV18-positive HeLa cervical carcinoma cells can be suppressed by fusion of HeLa cells with normal human keratinocytes or fibroblasts. We have addressed the question of whether suppression of tumorigenicity in HeLa x fibroblast hybrid cells might be due to a reduced ability of these cells to express the HPV18 E6-E7 genes in vivo. Nontumorigenic hybrid cells and tumorigenic hybrid segregants were transplanted as organotypical cultures or injected subcutaneously into immunocompromised mice and were analyzed for HPV18 E6-E7 gene expression by RNA-RNA in situ hybridization. The tumorigenic hybrid cells showed a continuous and invasive growth that was associated with high levels of HPV18 E6-E7 mRNAs at all time points examined. In contrast, the nontumorigenic hybrid cells stopped cell proliferation approximately 3 days after transplantation. At this time they expressed the E6-E7 genes at low levels, whereas at day 2 high expression levels were observed. However, the mRNA levels of the cytoskeletal genes beta-actin and vimentin remained high for at least 14 days, demonstrating that inhibition of growth and of HPV18 E6-E7 gene expression was not due to cell death. These results suggest that growth inhibition of the nontumorigenic HeLa x fibroblast hybrid cells in vivo might be caused by suppression of HPV18 E6-E7 gene expression and are compatible with the idea of an intracellular surveillance mechanism for HPV gene expression existing in nontumorigenic cells. Images PMID:2168962

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

    SciTech Connect

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

    2015-02-15

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

  17. Functional interactions of the cystine/glutamate antiporter, CD44v and MUC1-C oncoprotein in triple-negative breast cancer cells

    PubMed Central

    Hasegawa, Masanori; Takahashi, Hidekazu; Rajabi, Hasan; Alam, Maroof; Suzuki, Yozo; Yin, Li; Tagde, Ashujit; Maeda, Takahiro; Hiraki, Masayuki; Sukhatme, Vikas P.; Kufe, Donald

    2016-01-01

    The xCT light chain of the cystine/glutamate transporter (system XC−) is of importance for the survival of triple-negative breast cancer (TNBC) cells. The MUC1-C transmembrane oncoprotein is aberrantly overexpressed in TNBC and, like xCT, has been linked to maintaining glutathione (GSH) levels and redox balance. However, there is no known interaction between MUC1-C and xCT. Here we show that silencing MUC1-C is associated with decreases in xCT expression in TNBC cells. The results demonstrate that MUC1-C forms a complex with xCT and the CD44 variant (CD44v), which interacts with xCT and thereby controls GSH levels. MUC1-C binds directly with CD44v and in turn promotes stability of xCT in the cell membrane. The interaction between MUC1-C and xCT is further supported by the demonstration that targeting xCT with silencing or the inhibitor sulfasalazine suppresses MUC1 gene transcription by increasing histone and DNA methylation on the MUC1 promoter. In terms of the functional significance of the MUC1-C/xCT interaction, we show that MUC1-C protects against treatment with erastin, an inhibitor of XC− and inducer of ferroptosis, a form of non-apoptotic cell death. These findings indicate that targeting this novel MUC1-C/xCT pathway could represent a potential therapeutic approach for promoting TNBC cell death. PMID:26930718

  18. Specific recognition of four-way DNA junctions by the C-terminal zinc-binding domain of HPV oncoprotein E6.

    PubMed

    Ristriani, T; Nominé, Y; Masson, M; Weiss, E; Travé, G

    2001-01-26

    E6 is an oncoprotein implicated in cervical cancers produced by " high risk " human papillomaviruses. E6 binds specifically to several cellular proteins, including the tumour suppressor p53 and the ubiquitin ligase E6-AP. However, E6 is also a DNA-binding protein which recognizes a structural motive present in four-way junctions. Here, we demonstrate that the C-terminal zinc-binding domain of E6, expressed separately from the rest of the protein, fully retains the selective four-way junction recognition activity. The domain can bind to two identical and independent sites on a single junction, whereas full-length E6 can only bind to one site. The junction bound to either one or two domains adopts an extended square conformation. These results allow us to assign the structure-dependent DNA recognition activity of E6 to its C-terminal domain, which therefore represents a new class of zinc-stabilized DNA-binding module. Comparison with the binding characteristics of other junction-specific proteins enlightens the rules which govern protein-induced deformation of four-way DNA junctions. PMID:11162088

  19. Elucidation of Ligand-Dependent Modulation of Disorder-Order Transitions in the Oncoprotein MDM2

    PubMed Central

    Bueren-Calabuig, Juan A.; Michel, Julien

    2015-01-01

    Numerous biomolecular interactions involve unstructured protein regions, but how to exploit such interactions to enhance the affinity of a lead molecule in the context of rational drug design remains uncertain. Here clarification was sought for cases where interactions of different ligands with the same disordered protein region yield qualitatively different results. Specifically, conformational ensembles for the disordered lid region of the N-terminal domain of the oncoprotein MDM2 in the presence of different ligands were computed by means of a novel combination of accelerated molecular dynamics, umbrella sampling, and variational free energy profile methodologies. The resulting conformational ensembles for MDM2, free and bound to p53 TAD (17-29) peptide identify lid states compatible with previous NMR measurements. Remarkably, the MDM2 lid region is shown to adopt distinct conformational states in the presence of different small-molecule ligands. Detailed analyses of small-molecule bound ensembles reveal that the ca. 25-fold affinity improvement of the piperidinone family of inhibitors for MDM2 constructs that include the full lid correlates with interactions between ligand hydrophobic groups and the C-terminal lid region that is already partially ordered in apo MDM2. By contrast, Nutlin or benzodiazepinedione inhibitors, that bind with similar affinity to full lid and lid-truncated MDM2 constructs, interact additionally through their solubilizing groups with N-terminal lid residues that are more disordered in apo MDM2. PMID:26046940

  20. Functional and Structural Mimicry of Cellular Protein Kinase A Anchoring Proteins by a Viral Oncoprotein

    PubMed Central

    King, Cason R.; Cohen, Michael J.; Fonseca, Gregory J.; Dirk, Brennan S.; Dikeakos, Jimmy D.; Mymryk, Joe S.

    2016-01-01

    The oncoproteins of the small DNA tumor viruses interact with a plethora of cellular regulators to commandeer control of the infected cell. During infection, adenovirus E1A deregulates cAMP signalling and repurposes it for activation of viral gene expression. We show that E1A structurally and functionally mimics a cellular A-kinase anchoring protein (AKAP). E1A interacts with and relocalizes protein kinase A (PKA) to the nucleus, likely to virus replication centres, via an interaction with the regulatory subunits of PKA. Binding to PKA requires the N-terminus of E1A, which bears striking similarity to the amphipathic α-helical domain present in cellular AKAPs. E1A also targets the same docking-dimerization domain of PKA normally bound by cellular AKAPs. In addition, the AKAP like motif within E1A could restore PKA interaction to a cellular AKAP in which its normal interaction motif was deleted. During infection, E1A successfully competes with endogenous cellular AKAPs for PKA interaction. E1A’s role as a viral AKAP contributes to viral transcription, protein expression and progeny production. These data establish HAdV E1A as the first known viral AKAP. This represents a unique example of viral subversion of a crucial cellular regulatory pathway via structural mimicry of the PKA interaction domain of cellular AKAPs. PMID:27137912

  1. Role of the YAP Oncoprotein in Priming Ras-Driven Rhabdomyosarcoma

    PubMed Central

    Slemmons, Katherine K.; Crose, Lisa E. S.; Rudzinski, Erin; Bentley, Rex C.; Linardic, Corinne M.

    2015-01-01

    Rhabdomyosarcoma (RMS), a cancer characterized by features of skeletal muscle histogenesis, is the most common soft tissue sarcoma of childhood and adolescence. Survival for high-risk groups is less than 30% at 5 years. RMS also occurs during adulthood, with a lower incidence but higher mortality. Recently, mutational profiling has revealed a correlation between activating Ras mutations in the embryonal (eRMS) and pleomorphic (pRMS) histologic variants of RMS, and a poorer outcome for those patients. Independently, the YAP transcriptional coactivator, an oncoprotein kept in check by the Hippo tumor suppressor pathway, is upregulated in eRMS. Here we show that YAP promotes cell proliferation and antagonizes apoptosis and myogenic differentiation of human RMS cells bearing oncogenic Ras mutations in cell culture studies in vitro and in murine xenografts in vivo. Pharmacologic inhibition of YAP by the benzoporphyrin derivative verteporfin decreased cell proliferation and tumor growth in vivo. To interrogate the temporal contribution of YAP in eRMS tumorigenesis, we used a primary human cell-based genetic model of Ras-driven RMS. Constitutively active YAP functioned as an early genetic lesion, permitting bypass of senescence and priming myoblasts to tolerate subsequent expression of hTERT and oncogenic Ras, which were necessary and sufficient to generate murine xenograft tumors mimicking RMS in vivo. This work provides evidence for cooperation between YAP and oncogenic Ras in RMS tumorigenesis, laying the foundation for preclinical co-targeting of these pathways. PMID:26496700

  2. Role of the YAP Oncoprotein in Priming Ras-Driven Rhabdomyosarcoma.

    PubMed

    Slemmons, Katherine K; Crose, Lisa E S; Rudzinski, Erin; Bentley, Rex C; Linardic, Corinne M

    2015-01-01

    Rhabdomyosarcoma (RMS), a cancer characterized by features of skeletal muscle histogenesis, is the most common soft tissue sarcoma of childhood and adolescence. Survival for high-risk groups is less than 30% at 5 years. RMS also occurs during adulthood, with a lower incidence but higher mortality. Recently, mutational profiling has revealed a correlation between activating Ras mutations in the embryonal (eRMS) and pleomorphic (pRMS) histologic variants of RMS, and a poorer outcome for those patients. Independently, the YAP transcriptional coactivator, an oncoprotein kept in check by the Hippo tumor suppressor pathway, is upregulated in eRMS. Here we show that YAP promotes cell proliferation and antagonizes apoptosis and myogenic differentiation of human RMS cells bearing oncogenic Ras mutations in cell culture studies in vitro and in murine xenografts in vivo. Pharmacologic inhibition of YAP by the benzoporphyrin derivative verteporfin decreased cell proliferation and tumor growth in vivo. To interrogate the temporal contribution of YAP in eRMS tumorigenesis, we used a primary human cell-based genetic model of Ras-driven RMS. Constitutively active YAP functioned as an early genetic lesion, permitting bypass of senescence and priming myoblasts to tolerate subsequent expression of hTERT and oncogenic Ras, which were necessary and sufficient to generate murine xenograft tumors mimicking RMS in vivo. This work provides evidence for cooperation between YAP and oncogenic Ras in RMS tumorigenesis, laying the foundation for preclinical co-targeting of these pathways. PMID:26496700

  3. Fbw7 and its counteracting forces in stem cells and cancer: Oncoproteins in the balance.

    PubMed

    Cremona, Catherine A; Sancho, Rocio; Diefenbacher, Markus E; Behrens, Axel

    2016-02-01

    Fbw7 is well characterised as a stem cell regulator and tumour suppressor, powerfully positioned to control proliferation, differentiation and apoptosis by targeting key transcription factors for ubiquitination and destruction. Evidence in support of these roles continues to accumulate from in vitro studies, mouse models and human patient data. Here we summarise the latest of these findings, highlighting the tumour-suppressive role of Fbw7 in multiple tissues, and the rare circumstances where Fbw7 activity can be oncogenic. We discuss mechanisms that regulate ubiquitination by Fbw7, including ubiquitin-specific proteases such as USP28 that counteract Fbw7 activity and thereby stabilise oncoproteins. Deubiquitination of key Fbw7 substrates to prevent their destruction is beginning to be appreciated as an important pro-tumourigenic mechanism. As the ubiquitin-proteasome system represents a largely untapped field for drug development, the interplay between Fbw7 and its counterpart deubiquitinating enzymes in tumours is likely to attract increasing interest and influence future treatment strategies. PMID:26410034

  4. Defective human retinoblastoma protein identified by lack of interaction with the E1A oncoprotein.

    PubMed

    Paggi, M G; Martelli, F; Fanciulli, M; Felsani, A; Sciacchitano, S; Varmi, M; Bruno, T; Carapella, C M; Floridi, A

    1994-02-15

    Inactivating mutations of the retinoblastoma susceptibility gene (Rb) are involved in the pathogenesis of hereditary and sporadic retinoblastoma. Alterations in the Rb gene have also been found in several other human tumors occurring with epidemiological incidence higher than that of retinoblastoma. Four human malignant glioma cell lines were examined for abnormalities in the retinoblastoma gene product (pRb), using a procedure based on the interaction of pRb with an in vitro-translated adenovirus E1A oncoprotein. In the CRS-A2 cell line, derived from a glioblastoma multiforme, pRb did not bind with the in vitro-translated E1A protein. Restriction analysis of the CRS-A2 Rb gene and Rb mRNA expression provided patterns that could not be distinguished from the other glioma cell lines. Further investigation revealed the presence of a truncated pRb in the CRS-A2 cell line, due to a nucleotide insertion in the coding sequence at position 2550. In addition, this truncated Rb protein was undetectable in phosphorylated form. The binding assay with the in vitro-translated E1A was also used to study other cell lines with known mutations in the Rb gene. This method, which evaluates the interaction between in vitro-translated E1A and the pRb, is proposed as a rapid screening for detecting functional alterations in the retinoblastoma protein. PMID:8313367

  5. Impact of Ser17 Phosphorylation on the Conformational Dynamics of the Oncoprotein MDM2.

    PubMed

    Bueren-Calabuig, Juan A; Michel, Julien

    2016-05-01

    MDM2 is an important oncoprotein that downregulates the activity of the tumor suppressor protein p53 via binding of its N-terminal domain to the p53 transactivation domain. The first 24 residues of the MDM2 N-terminal domain form an intrinsically disordered "lid" region that interconverts on a millisecond time scale between "open" and "closed" states in unliganded MDM2. While the former conformational state is expected to facilitate p53 binding, the latter competes in a pseudo-substrate manner with p53 for its binding site. Phosphorylation of serine 17 in the MDM2 lid region is thought to modulate the equilibrium between "open" and "closed" lid states, but contradictory findings on the favored lid conformational state upon phosphorylation have been reported. Here, the nature of the conformational states of MDM2 pSer17 and Ser17Asp variants was addressed by means of enhanced sampling molecular dynamics simulations. Detailed analyses of the computed lid conformational ensembles indicate that both lid variants stabilize a "closed" state, with respect to wild type. Nevertheless, the nature of the closed-state conformational ensembles differs significantly between the pSer17 and Ser17Asp variants. Thus, care should be applied in the interpretation of biochemical experiments that use phosphomimetic variants to model the effects of phosphorylation on the structure and dynamics of this disordered protein region. PMID:27050388

  6. Aggregation In Heavy Water Micellar Dilute Solutions Of Three Nonionic Classic Surfactants: C10E7 AND C12E7 And C14E7 Study By SANS Method

    NASA Astrophysics Data System (ADS)

    Aldona, Rajewska

    2010-01-01

    Three nonionic classic surfactants C10E7 (heptaethylene glycol monodecyl ether) and C12E7 (heptaethylene glycol monododecyl ether) and C14E7 (heptaethylene glycol monotetradecyl ether) in water solutions were investigated for concentration c = 0.5% (dilute regime) at temperatures t = 6°, 10°, 15°, 20°, 25°, 30° and 35° C with two methods—tensiometric and small-angle neutron scattering ( SANS ) on SANS diffractometer "Yellow Submarine" at Budapest Neutron Center, Budapest ( Hungary ) and SANS spectrometer ("YuMO") of the IBR-2 on pulsed neutron source at FLNP, JINR in Dubna ( Russia ). Measurements have covered Q range from 8 10-3 to 0.4 Å-1. The micellar solutions were prepared in D2O since the contrast between the micelles and the solvent in neutron experiments is better with D2O than with H2O. It was obtained as the result that the shape of micelles changes depending on surfactant concentration and temperature. At lower concentrations and temperatures micelles are ellipsoids but at higher concentrations and temperature are rather cylinders. For calculation and approximation results from SANS experiments was used program PCG 2.0 of Glatter O. and co-workers from University of Graz (Austria).

  7. The footprint of E7(7) in amplitudes of Script N = 8 supergravity

    NASA Astrophysics Data System (ADS)

    Kallosh, Renata; Kugo, Taichiro

    2009-01-01

    We study the low energy theorems associated with the non-linearly realized continuous E7(7)(Bbb R) symmetry of the on-shell Script N = 8 supergravity. For Nambu-Goldstone bosons we evaluate the one-soft-scalar-boson emission amplitudes by computing the E7(7) current matrix element on the one-particle external lines. We use the explicit form of the conserved E7(7) Noether current and prove that all such matrix elements vanish in the soft momentum limit, assuming the SU(8) symmetry of the S-matrix. This implies that all tree amplitudes vanish in the one-soft-boson limit. We also discuss the implications of unbroken E7(7)(Bbb R) symmetry for higher-order amplitudes.

  8. 42 CFR 52e.7 - What are the terms and conditions of awards?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... by subpart Q of 45 CFR part 74. (b) The Director may permit unobligated grant funds remaining in the... HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the...

  9. 42 CFR 52e.7 - What are the terms and conditions of awards?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... by subpart Q of 45 CFR part 74. (b) The Director may permit unobligated grant funds remaining in the... HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the...

  10. 42 CFR 52e.7 - What are the terms and conditions of awards?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... by subpart Q of 45 CFR part 74. (b) The Director may permit unobligated grant funds remaining in the... HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the...

  11. 42 CFR 52e.7 - What are the terms and conditions of awards?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... by subpart Q of 45 CFR part 74. (b) The Director may permit unobligated grant funds remaining in the... HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the...

  12. 42 CFR 52e.7 - What are the terms and conditions of awards?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... by subpart Q of 45 CFR part 74. (b) The Director may permit unobligated grant funds remaining in the... HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the...

  13. 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

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

    2013-01-01

    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-γ 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-γ 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

  14. Combined stimulation of IL-2 and 4-1BB receptors augments the antitumor activity of E7 DNA vaccines by increasing Ag-specific CTL responses.

    PubMed

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

    2013-01-01

    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-γ 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-γ 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

  15. Detection of Human Papillomavirus-16 E6-Oncoprotein in Epithelial Ovarian Tumors Samples of Iraqi Patients

    PubMed Central

    Mahmood, Fahem Mohsin; Kadhim, Haider Sabah; Mousa Al Khuzaee, Liqaa Riadh

    2014-01-01

    Background: Human papillomavirus (HPV) is the causal factor for cervical cancer. However, the role of HPV infection in ovarian cancer is unclear. Objectives: This study aimed to determine the presence of human papillomavirus-16 (HPV-16) in ovarian tumor tissues. Patients and Methods: This was a retrospective study, which included 61 Archived human ovarian tumor tissues embedded in paraffin blocks. The ovarian tumor tissues were divided into four groups. The first group was the malignant ovarian epithelial tumor group; it included 31 cases with invasive surface epithelial ovarian tumors. The second group was the borderline epithelial ovarian tumor group: it included four cases with borderline intermediate malignancy. The third group was the benign epithelial ovarian tumors group: it included 18 cases with benign epithelial ovarian tumors. The fourth group had functional ovarian cystic lesions: it included eight cases with non-neoplastic functional ovarian cysts. Sections were made from each of the paraffin embedded blocks and examined using immunohistochemistry to detect HPV 16-E6-oncoprotein in ovarian tumor tissues. Results: Out of the eight cases with functional cysts only one case (12.5%) expressed HPV. No HPV expression was seen in cases with benign and borderline tumors. Out of the 31 cases with one malignant surface epithelial ovarian tumor only three (9.67%) cases expressed HPV. There was no significant statistical difference in HPV expression among neoplastic and non-neoplastic ovarian tumors included in the present study (P= 0.476). Conclusions: HPV type 16 was detected in only 9.67% of malignant epithelial tumors. It appears that HPV infection plays a relatively minor role in the pathogenesis of ovarian carcinomas. PMID:25485061

  16. A novel intracellular antibody against the E6 oncoprotein impairs growth of human papillomavirus 16-positive tumor cells in mouse models.

    PubMed

    Amici, Carla; Visintin, Michela; Verachi, Francesca; Paolini, Francesca; Percario, Zulema; Di Bonito, Paola; Mandarino, Angela; Affabris, Elisabetta; Venuti, Aldo; Accardi, Luisa

    2016-03-29

    Single-chain variable fragments (scFvs) expressed as "intracellular antibodies" (intrabodies) can target intracellular antigens to hamper their function efficaciously and specifically. Here we use an intrabody targeting the E6 oncoprotein of Human papillomavirus 16 (HPV16) to address the issue of a non-invasive therapy for HPV cancer patients.A scFv against the HPV16 E6 was selected by Intracellular Antibody Capture Technology and expressed as I7nuc in the nucleus of HPV16-positive SiHa, HPV-negative C33A and 293T cells. Colocalization of I7nuc and recombinant E6 was observed in different cell compartments, obtaining evidence of E6 delocalization ascribable to I7nuc. In SiHa cells, I7nuc expressed by pLNCX retroviral vector was able to partially inhibit degradation of the main E6 target p53, and induced p53 accumulation in nucleus. When analyzing in vitro activity on cell proliferation and survival, I7nuc was able to decrease growth inducing late apoptosis and necrosis of SiHa cells.Finally, I7nuc antitumor activity was demonstrated in two pre-clinical models of HPV tumors. C57BL/6 mice were injected subcutaneously with HPV16-positive TC-1 or C3 tumor cells, infected with pLNCX retroviral vector expressing or non-expressing I7nuc. All the mice injected with I7nuc-expressing cells showed a clear delay in tumor onset; 60% and 40% of mice receiving TC-1 and C3 cells, respectively, remained tumor-free for 17 weeks of follow-up, whereas 100% of the controls were tumor-bearing 20 days post-inoculum. Our data support the therapeutic potential of E6-targeted I7nuc against HPV tumors. PMID:26788990

  17. E4BP4 expression is regulated by the t(17;19)-associated oncoprotein E2A-HLF in pro-B cells.

    PubMed

    Yeung, Jenny; O'Sullivan, Elaine; Hubank, Mike; Brady, Hugh J M

    2004-06-01

    The E4BP4 basic leucine zipper (bZIP) transcription factor is regulated by interleukin-3 (IL-3) in pro-B cells and has been reported to promote survival of the murine IL-3-dependent pro-B cell lines, FL5.12 and Baf-3. The E2A-HLF oncoprotein arises from a t(17;19) translocation in childhood pro-B cell acute lymphoblastic leukaemia and acts as an anti-apoptotic factor in FL5.12 and Baf-3 cells. To assess the functions of E2A-HLF and E4BP4 in cell survival, a tetracycline-inducible system was established in Baf-3 cells to express E4BP4 or E2A-HLF. Upon IL-3 withdrawal, expression of E2A-HLF conferred resistance to apoptosis whereas overexpression of E4BP4 did not. E4BP4 and E2A-HLF both recognized the same DNA sequence in reporter gene assays, but had opposite effects on transcription. E2A-HLF acts as a transcriptional activator and E4BP4 as a transcriptional repressor. Furthermore, E4BP4 is a downstream transcriptional target of E2A-HLF. Our data suggests that the overexpression of E4BP4 is unable to block apoptosis induced by IL-3 withdrawal and that the expression of E2A-HLF does not replace the function of E4BP4 in mediating survival. PMID:15147370

  18. A novel intracellular antibody against the E6 oncoprotein impairs growth of human papillomavirus 16-positive tumor cells in mouse models

    PubMed Central

    Amici, Carla; Visintin, Michela; Verachi, Francesca; Paolini, Francesca; Percario, Zulema; Di Bonito, Paola; Mandarino, Angela; Affabris, Elisabetta; Venuti, Aldo; Accardi, Luisa

    2016-01-01

    Single-chain variable fragments (scFvs) expressed as “intracellular antibodies” (intrabodies) can target intracellular antigens to hamper their function efficaciously and specifically. Here we use an intrabody targeting the E6 oncoprotein of Human papillomavirus 16 (HPV16) to address the issue of a non-invasive therapy for HPV cancer patients. A scFv against the HPV16 E6 was selected by Intracellular Antibody Capture Technology and expressed as I7nuc in the nucleus of HPV16-positive SiHa, HPV-negative C33A and 293T cells. Colocalization of I7nuc and recombinant E6 was observed in different cell compartments, obtaining evidence of E6 delocalization ascribable to I7nuc. In SiHa cells, I7nuc expressed by pLNCX retroviral vector was able to partially inhibit degradation of the main E6 target p53, and induced p53 accumulation in nucleus. When analyzing in vitro activity on cell proliferation and survival, I7nuc was able to decrease growth inducing late apoptosis and necrosis of SiHa cells. Finally, I7nuc antitumor activity was demonstrated in two pre-clinical models of HPV tumors. C57BL/6 mice were injected subcutaneously with HPV16-positive TC-1 or C3 tumor cells, infected with pLNCX retroviral vector expressing or non-expressing I7nuc. All the mice injected with I7nuc-expressing cells showed a clear delay in tumor onset; 60% and 40% of mice receiving TC-1 and C3 cells, respectively, remained tumor-free for 17 weeks of follow-up, whereas 100% of the controls were tumor-bearing 20 days post-inoculum. Our data support the therapeutic potential of E6-targeted I7nuc against HPV tumors. PMID:26788990

  19. The Canine Papillomavirus and Gamma HPV E7 Proteins Use an Alternative Domain to Bind and Destabilize the Retinoblastoma Protein

    PubMed Central

    Wang, Jingang; Zhou, Dan; Prabhu, Anjali; Schlegel, Richard; Yuan, Hang

    2010-01-01

    The high-risk HPV E6 and E7 proteins cooperate to immortalize primary human cervical cells and the E7 protein can independently transform fibroblasts in vitro, primarily due to its ability to associate with and degrade the retinoblastoma tumor suppressor protein, pRb. The binding of E7 to pRb is mediated by a conserved Leu-X-Cys-X-Glu (LXCXE) motif in the conserved region 2 (CR2) of E7 and this domain is both necessary and sufficient for E7/pRb association. In the current study, we report that the E7 protein of the malignancy-associated canine papillomavirus type 2 encodes an E7 protein that has serine substituted for cysteine in the LXCXE motif. In HPV, this substitution in E7 abrogates pRb binding and degradation. However, despite variation at this critical site, the canine papillomavirus E7 protein still bound and degraded pRb. Even complete deletion of the LXSXE domain of canine E7 failed to interfere with binding to pRb in vitro and in vivo. Rather, the dominant binding site for pRb mapped to the C-terminal domain of canine E7. Finally, while the CR1 and CR2 domains of HPV E7 are sufficient for degradation of pRb, the C-terminal region of canine E7 was also required for pRb degradation. Screening of HPV genome sequences revealed that the LXSXE motif of the canine E7 protein was also present in the gamma HPVs and we demonstrate that the gamma HPV-4 E7 protein also binds pRb in a similar way. It appears, therefore, that the type 2 canine PV and gamma-type HPVs not only share similar properties with respect to tissue specificity and association with immunosuppression, but also the mechanism by which their E7 proteins interact with pRb. PMID:20824099

  20. NF-κB signalling is attenuated by the E7 protein from cutaneous human papillomaviruses.

    PubMed

    Byg, Luise M; Vidlund, Jessica; Vasiljevic, Natasa; Clausen, Dorte; Forslund, Ola; Norrild, Bodil

    2012-10-01

    The high-risk Alpha-types of human papillomavirus (HPV) are the causative agent of cervical cancer, which is the second major cause of death among women worldwide. Recent investigations have shown that E7 from the Alpha-papillomavirus HPV-16 interacts with IKKα and IKKβ of the IKK complex in the NF-κB pathway leading to an attenuation of the activity. There is a possible link between development of non-melanoma skin cancer and cutaneous Beta-papillomavirus but if these HPV types attenuate the NF-κB pathway is unclear. Seven different E7 proteins, representing four out of the five different species of the Beta genus (HPV-20, -37, -38, -92, -93 and -96) and one from the Gamma genus (HPV-4) were investigated for potential modulation of the NF-κB pathway in U2OS cells. Our results demonstrate that E7 from all the cutaneous HPV types were capable of inhibiting the NF-κB activity as well as E7 from HPV-16. In addition, E7 proteins from the cutaneous HPV types demonstrated interaction with IKKα but not with IKKβ. The deregulation of the NF-κB pathway by cutaneous HPVs might contribute to the pathogenesis of non-melanoma skin cancers and its precursors. PMID:22776252

  1. Novel DNA binding specificities of a putative herpesvirus bZIP oncoprotein.

    PubMed Central

    Qian, Z; Brunovskis, P; Lee, L; Vogt, P K; Kung, H J

    1996-01-01

    Marek's disease virus is a highly oncogenic herpesvirus that can cause T lymphomas and peripheral nerve demyelination in chickens. meq, a candidate oncogene of Marek's disease virus, encodes a basic leucine zipper (bZIP) transcription factor which contains a large proline-rich domain in its C terminus. On the basis of its bZIP structural homology, meq is perhaps the only member of the jun-fos gene family completely viral in origin. We previously showed that Meq's C-terminal domain has potent transactivation activity and that its bZIP domain can dimerize with itself and with c-Jun also. In an effort to identify viral and cellular targets of Meq, we have determined the optimal binding sites for Meq-Jun heterodimers and Meq-Meq homodimers. By a PCR-based approach using cyclic amplification of selected targets, Meq-Jun heterodimers were found to optimally bind tetradecanoylphorbol acetate response element (TRE) and cyclic AMP response element (CRE) consensus sequences. This result was consistent with the results of our previous functional analysis implicating Meq-Jun heterodimers in the transactivation of the Meq promoter through a TRE- or CRE-like sequence. Interestingly, Meq-Meq homodimers were found to bind two distinct motif elements. The first [GAGTGATG AC(G)TCATC] has a consensus which includes a TRE or CRE core flanked by additional nucleotides critical for tight binding. Methylation interference and mutational analyses confirmed the importance of the flanking residues. The sequences of a subset of TRE and CRE sites selected by Meq-Meq are closely related to the binding motif of Maf, another bZIP oncoprotein. The second putative Meq binding site (RACACACAY) bears a completely different consensus not shared by other bZIP proteins. Binding to this consensus sequence also requires secondary structure characteristics associated with DNA bending. CACA motifs are known to promote DNA curvature and function in a number of special biological processes. Our results lend

  2. Multifaceted Role of IRAK-M in the Promotion of Colon Carcinogenesis via Barrier Dysfunction and STAT3 Oncoprotein Stabilization in Tumors.

    PubMed

    Jenkins, Brendan J

    2016-05-01

    Dysregulated interactions between the host immune system and gut microbiota can underpin inflammation, leading to colorectal cancer (CRC). In this issue of Cancer Cell, Kesselring et al. reveal a bimodal role of the TLR/IL-1R-signaling negative regulator, IRAK-M, in promoting tumoral microbial colonization and STAT3 oncoprotein stabilization during CRC. PMID:27165738

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

    PubMed Central

    DeCaprio, James A.

    2014-01-01

    Study of the small DNA tumor viruses continues to provide valuable new insights into oncogenesis and fundamental biological processes. While much has already been revealed about how the human papillomaviruses (HPVs) can transform cells and contribute to cervical and oropharyngeal cancer, there clearly is much more to learn. In this issue of Oncogene, Pang et al. demonstrate that the high-risk HPV16 E7 oncogene can promote cellular proliferation by interacting with the DREAM (DP, RB-like, E2F and MuvB) complex at two distinct phases of the cell cycle (1). Consistent with earlier work, HPV16 E7 can bind to the retinoblastoma tumor suppressor (RB) family member p130 (RBL2) protein and promote its proteasome-mediated destruction thereby disrupting the DREAM complex and prevent exit from the cell cycle into quiescence. In addition, they demonstrate that HPV16 E7 can bind to MuvB core complex in association with BMYB and FOXM1 and activate gene expression during the G2 and M phase of the cell cycle. Thus, HPV16 E7 acts to prevent exit from the cell cycle entry and promotes mitotic proliferation and may account for the high levels of FOXM1 often observed in poor risk cervical cancers. PMID:24166507

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

    PubMed

    DeCaprio, J A

    2014-07-31

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

  5. 77 FR 9948 - International Conference on Harmonisation; Guidance on E7 Studies in Support of Special...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-21

    .... In the Federal Register of November 10, 2009 (74 FR 58024), FDA published a notice announcing the... Studies in Support of Special Populations; Geriatrics; Questions and Answers; Availability AGENCY: Food... announcing the availability of a guidance entitled ``E7 Studies in Support of Special Populations:...

  6. Loss of Dependence on Continued Expression of the Human Papillomavirus 16 E7 Oncogene in Cervical Cancers and Precancerous Lesions Arising in Fanconi Anemia Pathway-Deficient Mice

    PubMed Central

    Park, Soyeong; Park, Jung Wook; Pitot, Henry C.

    2016-01-01

    ABSTRACT   Fanconi anemia (FA) is a rare genetic disorder caused by defects in DNA damage repair. FA patients often develop squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) are known to cause cancer, including the cervix. However, SCCs found in human FA patients are often HPV negative, even though the majority of female FA patients with anogenital cancers had preexisting HPV-positive dysplasia. We hypothesize that HPVs contribute to the development of SCCs in FA patients but that the continued expression of HPV oncogenes is not required for the maintenance of the cancer state because FA deficiency leads to an accumulation of mutations in cellular genes that render the cancer no longer dependent upon viral oncogenes. We tested this hypothesis, making use of Bi-L E7 transgenic mice in which we temporally controlled expression of HPV16 E7, the dominant viral oncogene in HPV-associated cancers. As seen before, the persistence of cervical neoplastic disease was highly dependent upon the continued expression of HPV16 E7 in FA-sufficient mice. However, in mice with FA deficiency, cervical cancers persisted in a large fraction of the mice after HPV16 E7 expression was turned off, indicating that these cancers had escaped from their dependency on E7. Furthermore, the severity of precancerous lesions also failed to be reduced significantly in the mice with FA deficiency upon turning off expression of E7. These findings confirm our hypothesis and may explain the fact that, while FA patients have a high frequency of infections by HPVs and HPV-induced precancerous lesions, the cancers are frequently HPV negative. Importance   Fanconi anemia (FA) patients are at high risk for developing squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) frequently cause cancer. Yet these SCCs are often HPV negative. FA patients have a genetic defect in their capacity to repair damaged DNA. HPV oncogenes cause an

  7. Loss of Dependence on Continued Expression of the Human Papillomavirus 16 E7 Oncogene in Cervical Cancers and Precancerous Lesions Arising in Fanconi Anemia Pathway-Deficient Mice.

    PubMed

    Park, Soyeong; Park, Jung Wook; Pitot, Henry C; Lambert, Paul F

    2016-01-01

    Fanconi anemia (FA) is a rare genetic disorder caused by defects in DNA damage repair. FA patients often develop squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) are known to cause cancer, including the cervix. However, SCCs found in human FA patients are often HPV negative, even though the majority of female FA patients with anogenital cancers had preexisting HPV-positive dysplasia. We hypothesize that HPVs contribute to the development of SCCs in FA patients but that the continued expression of HPV oncogenes is not required for the maintenance of the cancer state because FA deficiency leads to an accumulation of mutations in cellular genes that render the cancer no longer dependent upon viral oncogenes. We tested this hypothesis, making use of Bi-L E7 transgenic mice in which we temporally controlled expression of HPV16 E7, the dominant viral oncogene in HPV-associated cancers. As seen before, the persistence of cervical neoplastic disease was highly dependent upon the continued expression of HPV16 E7 in FA-sufficient mice. However, in mice with FA deficiency, cervical cancers persisted in a large fraction of the mice after HPV16 E7 expression was turned off, indicating that these cancers had escaped from their dependency on E7. Furthermore, the severity of precancerous lesions also failed to be reduced significantly in the mice with FA deficiency upon turning off expression of E7. These findings confirm our hypothesis and may explain the fact that, while FA patients have a high frequency of infections by HPVs and HPV-induced precancerous lesions, the cancers are frequently HPV negative. IMPORTANCE  : Fanconi anemia (FA) patients are at high risk for developing squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) frequently cause cancer. Yet these SCCs are often HPV negative. FA patients have a genetic defect in their capacity to repair damaged DNA. HPV oncogenes cause an accumulation of DNA

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

    PubMed

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

    2015-06-01

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

  9. The DEK Oncoprotein Is a Critical Component of the EKLF/KLF1 Enhancer in Erythroid Cells

    PubMed Central

    Lohmann, Felix; Dangeti, Mohan; Soni, Shefali; Chen, Xiaoyong; Planutis, Antanas; Baron, Margaret H.; Choi, Kyunghee

    2015-01-01

    Understanding how transcriptional regulators are themselves controlled is important in attaining a complete picture of the intracellular effects that follow signaling cascades during early development and cell-restricted differentiation. We have addressed this issue by focusing on the regulation of EKLF/KLF1, a zinc finger transcription factor that plays a necessary role in the global regulation of erythroid gene expression. Using biochemical affinity purification, we have identified the DEK oncoprotein as a critical factor that interacts with an essential upstream enhancer element of the EKLF promoter and exerts a positive effect on EKLF levels. This element also binds a core set of erythroid transcription factors, suggesting that DEK is part of a tissue-restricted enhanceosome that contains BMP4-dependent and -independent components. Together with local enrichment of properly coded histones and an open chromatin domain, optimal transcriptional activation of the EKLF locus can be established. PMID:26303528

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

    PubMed Central

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

    1998-01-01

    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

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

    SciTech Connect

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

    2012-08-10

    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

  12. 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

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

    2013-01-01

    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

  13. 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

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

    2013-01-01

    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

  14. Identification of the murine H-2D(b) and human HLA-A*0201 MHC class I-restricted HPV6 E7-specific cytotoxic T lymphocyte epitopes.

    PubMed

    Peng, Shiwen; Mattox, Austin; Best, Simon R; Barbu, Anca M; Burns, James A; Akpeng, Belinda; Jeang, Jessica; Yang, Benjamin; Ishida, Eiichi; Hung, Chien-Fu; Wu, Tzyy-Choou; Pai, Sara I

    2016-03-01

    Recurrent respiratory papillomatosis is caused by human papillomavirus (HPV) infection, most commonly types 6 (HPV-6) and 11 (HPV-11). Due to failed host immune responses, HPV is unable to be cleared from the host, resulting in recurrent growth of HPV-related lesions that can obstruct the lumen of the airway within the upper aerodigestive tract. In our murine model, the HPV-6b and HPV-11 E7 antigens are not innately immunogenic. In order to enhance the host immune responses against the HPV E7 antigen, we linked calreticulin (CRT) to HPV-6b E7 and found that vaccinating C57BL/6 mice with the HPV-6b CRT/E7 DNA vaccine is able to induce a CD8+ T cell response that recognizes an H-2D(b)-restricted E7aa21-29 epitope. Additionally, vaccination of HLA-A*0201 transgenic mice with HPV-6b CRT/E7 DNA generated a CD8+ T cell response against the E7aa82-90 epitope that was not observed in the wild-type C57BL/6 mice, indicating this T cell response is restricted to HLA-A*0201. In vivo cytotoxic T cell killing assays demonstrated that the vaccine-induced CD8+ T cells are able to efficiently kill target cells. Interestingly, the H-2D(b)-restricted E7aa21-29 sequence and the HLA-A*0201-restricted E7aa82-90 sequence are conserved between HPV-6b and HPV-11 and may represent shared immunogenic epitopes. The identification of the HPV-6b/HPV-11 CD8+ T cell epitopes facilitates the evaluation of various immunomodulatory strategies in preclinical models. More importantly, the identified HLA-A*0201-restricted T cell epitope may serve as a peptide vaccination strategy, as well as facilitate the monitoring of vaccine-induced HPV-specific immunologic responses in future human clinical trials. PMID:26759151

  15. Characterization of the transport signals that mediate the nucleocytoplasmic traffic of low risk HPV11 E7

    SciTech Connect

    McKee, Courtney H.; Onder, Zeynep; Ashok, Aditya; Cardoso, Rebeca; Moroianu, Junona

    2013-08-15

    We previously discovered that nuclear import of low risk HPV11 E7 is mediated by its zinc-binding domain via a pathway that is independent of karyopherins/importins (Piccioli et al., 2010. Virology 407, 100–109). In this study we mapped and characterized a leucine-rich nuclear export signal (NES), {sub 76}IRQLQDLLL{sub 84}, within the zinc-binding domain that mediates the nuclear export of HPV11 E7 in a CRM1-dependent manner. We also identified a mostly hydrophobic patch {sub 65}VRLVV{sub 69} within the zinc-binding domain that mediates nuclear import of HPV11 E7 via hydrophobic interactions with the FG-repeats domain of Nup62. Substitutions of hydrophobic residues to alanine within the {sub 65}VRLVV{sub 69} sequence disrupt the nuclear localization of 11E7, whereas the R66A mutation has no effect. Overall the data support a model of nuclear entry of HPV11 E7 protein via hydrophobic interactions with FG nucleoporins at the nuclear pore complex. - Highlights: • HPV11 E7 has a leucine-rich nuclear export signal that mediates its nuclear export via CRM1. • HPV11 E7 interacts via its unique cNLS with the FG domain of Nup62. • Identification of a hydrophobic patch essential for nuclear localization of HPV11 E7.

  16. 17 CFR 240.14e-7 - Unlawful tender offer practices in connection with roll-ups.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Unlawful tender offer practices in connection with roll-ups. 240.14e-7 Section 240.14e-7 Commodity and Securities Exchanges... tender offer practices in connection with roll-ups. In order to implement section 14(h) of the Act (15...

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Unlawful tender offer practices in connection with roll-ups. 240.14e-7 Section 240.14e-7 Commodity and Securities Exchanges... tender offer practices in connection with roll-ups. In order to implement section 14(h) of the Act (15...

  18. 17 CFR 240.14e-7 - Unlawful tender offer practices in connection with roll-ups.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Unlawful tender offer practices in connection with roll-ups. 240.14e-7 Section 240.14e-7 Commodity and Securities Exchanges... tender offer practices in connection with roll-ups. In order to implement section 14(h) of the Act (15...

  19. 17 CFR 240.14e-7 - Unlawful tender offer practices in connection with roll-ups.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Unlawful tender offer practices in connection with roll-ups. 240.14e-7 Section 240.14e-7 Commodity and Securities Exchanges... tender offer practices in connection with roll-ups. In order to implement section 14(h) of the Act (15...

  20. 17 CFR 240.14e-7 - Unlawful tender offer practices in connection with roll-ups.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... practices in connection with roll-ups. 240.14e-7 Section 240.14e-7 Commodity and Securities Exchanges... tender offer practices in connection with roll-ups. In order to implement section 14(h) of the Act (15 U... tenders directly from security holders in connection with a roll-up transaction as provided in...

  1. Aptamer-hybrid nanoparticle bioconjugate efficiently delivers miRNA-29b to non-small-cell lung cancer cells and inhibits growth by downregulating essential oncoproteins

    PubMed Central

    Perepelyuk, Maryna; Maher, Christina; Lakshmikuttyamma, Ashakumary; Shoyele, Sunday A

    2016-01-01

    MicroRNAs (miRNAs) are potentially attractive candidates for cancer therapy. However, their therapeutic application is limited by lack of availability of an efficient delivery system to stably deliver these potent molecules intracellularly to cancer cells while avoiding healthy cells. We developed a novel aptamer-hybrid nanoparticle bioconjugate delivery system to selectively deliver miRNA-29b to MUC1-expressing cancer cells. Significant downregulation of oncoproteins DNMT3b and MCL1 was demonstrated by these MUC1 aptamer-functionalized hybrid nanoparticles in A549 cells. Furthermore, downregulation of these oncoproteins led to antiproliferative effect and induction of apoptosis in a superior version when compared with Lipofectamine 2000. This novel aptamer-hybrid nanoparticle bioconjugate delivery system could potentially serve as a platform for intracellular delivery of miRNAs to cancer cells, hence improving the therapeutic outcome of lung cancer. PMID:27555773

  2. Aptamer-hybrid nanoparticle bioconjugate efficiently delivers miRNA-29b to non-small-cell lung cancer cells and inhibits growth by downregulating essential oncoproteins.

    PubMed

    Perepelyuk, Maryna; Maher, Christina; Lakshmikuttyamma, Ashakumary; Shoyele, Sunday A

    2016-01-01

    MicroRNAs (miRNAs) are potentially attractive candidates for cancer therapy. However, their therapeutic application is limited by lack of availability of an efficient delivery system to stably deliver these potent molecules intracellularly to cancer cells while avoiding healthy cells. We developed a novel aptamer-hybrid nanoparticle bioconjugate delivery system to selectively deliver miRNA-29b to MUC1-expressing cancer cells. Significant downregulation of oncoproteins DNMT3b and MCL1 was demonstrated by these MUC1 aptamer-functionalized hybrid nanoparticles in A549 cells. Furthermore, downregulation of these oncoproteins led to antiproliferative effect and induction of apoptosis in a superior version when compared with Lipofectamine 2000. This novel aptamer-hybrid nanoparticle bioconjugate delivery system could potentially serve as a platform for intracellular delivery of miRNAs to cancer cells, hence improving the therapeutic outcome of lung cancer. PMID:27555773

  3. MicroRNA-27b up-regulated by human papillomavirus 16 E7 promotes proliferation and suppresses apoptosis by targeting polo-like kinase2 in cervical cancer

    PubMed Central

    Zhao, Zhen; Mao, Xinru; Huang, Jinlan; Wu, Zixian; Zheng, Lei; Wang, Qian

    2016-01-01

    The infection with high-risk human papillomavirus is linked to cervical cancer, nevertheless, the role of miRNAs regulated by HPV oncogenes in cancer progression remain largely unknown. Here, we knocked down endogenous E6/E7 in HPV16-positive CaSki cell lines, screened differences in miRNA expression profile with control using miRNA array. 38 miRNAs were down-regulated and 6 miRNAs were up-regulated in the E6/E7 silenced CaSki cells (>2-fold changes with P <0.05). The levels of miR-27b, miR-20a, miR-24, miR-93, and miR-106b were verified by qPCR in E6/E7 silenced CaSki and SiHa cells. MiR-27b, up-regulated by E7, promoted CaSki and SiHa cell proliferation and invasion, inhibit paclitaxel-induced apoptosis. Dual-luciferase experiment confirmed miR-27b down-regulated its target gene PLK2 through the “seed regions”. The tumor suppressor PLK2 inhibited SiHa cell proliferation, reduced cell viability, and promoted paclitaxel/cisplatin -induced apoptosis. Furthermore, DGCR8 was found to mediate the up-regulation of miR-27b by HPV16 E7. Our study demonstrated that HPV16 E7 could increase DGCR8 to promote the generation of miR-27b, which accelerated cell proliferation and inhibited paclitaxel-induced cell apoptosis through down-regulating PLK2. These findings provide an insight into the interaction network of viral oncogene, miR-27b and PLK2, and support the potential strategies using antisense nucleic acid of miR-27b for therapy of cervical cancer in the future. PMID:26910911

  4. Simulation evaluation of transition and hover flying qualities of the E-7A STOVL aircraft

    NASA Technical Reports Server (NTRS)

    Franklin, James A.; Stortz, Michael W.; Gerdes, Ronald M.; Hardy, Gordon H.; Martin, James L.; Engelland, Shawn A.

    1988-01-01

    The generalized simulation model developed for the E-7A STOVL fighter-type aircraft configuration has attempted to define the limits of acceptibility for a vertical-to-horizontal-to-vertical flight transition envelope. An effort was also made to determine the control power required during hover and transition, and to evaluate whether the integration of flight and propulsion controls thus far effected achieves good flying qualities throughout the low-speed flight envelope. The results thus obtained furnish a general view of the acceptable transition corridor, expressed in terms of the minimum-climb capability.

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

    PubMed Central

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

    2013-01-01

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

  6. Mutagenic Potential ofBos taurus Papillomavirus Type 1 E6 Recombinant Protein: First Description

    PubMed Central

    Araldi, Rodrigo Pinheiro; Mazzuchelli-de-Souza, Jacqueline; Modolo, Diego Grando; de Souza, Edislane Barreiros; de Melo, Thatiana Corrêa; Spadacci-Morena, Diva Denelle; Magnelli, Roberta Fiusa; de Carvalho, Márcio Augusto Caldas Rocha; de Sá Júnior, Paulo Luis; de Carvalho, Rodrigo Franco; Beçak, Willy; Stocco, Rita de Cassia

    2015-01-01

    Bovine papillomavirus (BPV) is considered a useful model to study HPV oncogenic process. BPV interacts with the host chromatin, resulting in DNA damage, which is attributed to E5, E6, and E7 viral oncoproteins activity. However, the oncogenic mechanisms of BPV E6 oncoprotein per se remain unknown. This study aimed to evaluate the mutagenic potential of Bos taurus papillomavirus type 1 (BPV-1) E6 recombinant oncoprotein by the cytokinesis-block micronucleus assay (CBMNA) and comet assay (CA). Peripheral blood samples of five calves were collected. Samples were subjected to molecular diagnosis, which did not reveal presence of BPV sequences. Samples were treated with 1 μg/mL of BPV-1 E6 oncoprotein and 50 μg/mL of cyclophosphamide (positive control). Negative controls were not submitted to any treatment. The samples were submitted to the CBMNA and CA. The results showed that BPV E6 oncoprotein induces clastogenesis per se, which is indicative of genomic instability. These results allowed better understanding the mechanism of cancer promotion associated with the BPV E6 oncoprotein and revealed that this oncoprotein can induce carcinogenesis per se. E6 recombinant oncoprotein has been suggested as a possible vaccine candidate. Results pointed out that BPV E6 recombinant oncoprotein modifications are required to use it as vaccine. PMID:26783529

  7. Adjuvant effect of docetaxel on HPV16 L2E6E7 fusion protein vaccine in a mouse model.

    PubMed

    Su, Xiaoyan; Xu, Wei; Guan, Ran; Wang, Yunhao; Wu, Jie; Zhai, Lijuan; Chen, Gang; Hu, Songhua

    2016-09-01

    We previously demonstrated that the antineoplastic agent docetaxel enhanced the immune response to an influenza vaccine. This study evaluated the adjuvant effect of docetaxel (DOC) on the therapeutic efficacy of HPV16 L2E6E7 fusion protein (HPV-LFP) in mice inoculated with TC-1 cells. The results demonstrated that docetaxel significantly enhanced the therapeutic effect of HPV-LFP on TC-1 cell-induced tumors in mice. The injection of HPV-LFP in combination with docetaxel in TC-1 tumor-bearing mice significantly reduced tumor volume and weight, and a greater percent survival was detected than mice treated with HPV-LFP alone. The inhibition of tumors was associated with significantly increased serum antigen-specific IgG and isotypes, activated CTLs, increased IFN-γ-secreting T cells, and decreased Treg cells and IL-10-secreting cells in spleen. In addition, down-regulation of IL-10, VEGF and STAT3, up-regulation of IFN-γ and decreased Treg cells in the tumor microenvironment may also important contributing factors to the antitumor effect. It may be valuable to use a DOC-containing water to dilute HPV-LFP powder before injection in patients because of its excellent adjuvant effect on HPV-LFP and solubility in water. PMID:27233002

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

    SciTech Connect

    Zhang, Yingyi; Zhao, Yu; Li, Leilei; Shen, Yu; Cai, Xiaoli; Zhang, Xiaodong; Ye, Lihong

    2013-05-03

    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-κB (NF-κB) 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-κB 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.

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

    SciTech Connect

    Kaur, Tranum; Gupta, Rajesh; Vaiphei, Kim; Kapoor, Rakesh; Gupta, N.M.; Khanduja, K.L.

    2008-02-01

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

  10. Competitive Inhibition of Lysine Acetyltransferase 2B by a Small Motif of the Adenoviral Oncoprotein E1A.

    PubMed

    Shi, Shasha; Liu, Ke; Chen, Yanheng; Zhang, Shijun; Lin, Juanyu; Gong, Chenfang; Jin, Quanwen; Yang, Xiang-Jiao; Chen, Ruichuan; Ji, Zhiliang; Han, Aidong

    2016-07-01

    The adenovirus early region 1A (E1A) oncoprotein hijacks host cells via direct interactions with many key cellular proteins, such as KAT2B, also known as PCAF (p300/CBP associated factor). E1A binds the histone acetyltransferase (HAT) domain of KAT2B to repress its transcriptional activation. However, the molecular mechanism by which E1A inhibits the HAT activity is not known. Here we demonstrate that a short and relatively conserved N-terminal motif (cNM) in the intrinsically disordered E1A protein is crucial for KAT2B interaction, and inhibits its HAT activity through a direct competition with acetyl-CoA, but not its substrate histone H3. Molecular modeling together with a series of mutagenesis experiments suggests that the major helix of E1A cNM binds to a surface of the acetyl-CoA pocket of the KAT2B HAT domain. Moreover, transient expression of the cNM peptide is sufficient to inhibit KAT2B-specific H3 acetylation H3K14ac in vivo Together, our data define an essential motif cNM in N-terminal E1A as an acetyl-CoA entry blocker that directly associates with the entrance of acetyl-CoA binding pocket to block the HAT domain access to its cofactor. PMID:27143356

  11. Discovery of a small-molecule binder of the oncoprotein gankyrin that modulates gankyrin activity in the cell

    PubMed Central

    Chattopadhyay, Anasuya; O’Connor, Cornelius J.; Zhang, Fengzhi; Galvagnion, Celine; Galloway, Warren R. J. D.; Tan, Yaw Sing; Stokes, Jamie E.; Rahman, Taufiq; Verma, Chandra; Spring, David R.; Itzhaki, Laura S.

    2016-01-01

    Gankyrin is an ankyrin-repeat oncoprotein whose overexpression has been implicated in the development of many cancer types. Elevated gankyrin levels are linked to aberrant cellular events including enhanced degradation of tumour suppressor protein p53, and inhibition of gankyrin activity has therefore been identified as an attractive anticancer strategy. Gankyrin interacts with several partner proteins, and a number of these protein-protein interactions (PPIs) are of relevance to cancer. Thus, molecules that bind the PPI interface of gankyrin and interrupt these interactions are of considerable interest. Herein, we report the discovery of a small molecule termed cjoc42 that is capable of binding to gankyrin. Cell-based experiments demonstrate that cjoc42 can inhibit gankyrin activity in a dose-dependent manner: cjoc42 prevents the decrease in p53 protein levels normally associated with high amounts of gankyrin, and it restores p53-dependent transcription and sensitivity to DNA damage. The results represent the first evidence that gankyrin is a “druggable” target with small molecules. PMID:27046077

  12. A plant alkaloid, veratridine, potentiates cancer chemosensitivity by UBXN2A-dependent inhibition of an oncoprotein, mortalin-2

    PubMed Central

    Abdullah, Ammara; Sane, Sanam; Branick, Kate A.; Freeling, Jessica L.; Wang, Hongmin; Zhang, Dong; Rezvani, Khosrow

    2015-01-01

    Veratridine (VTD), an alkaloid derived from the Liliaceae plant shows anti-tumor effects; however, its molecular targets have not been thoroughly studied. Using a high-throughput drug screen, we found that VTD enhances transactivation of UBXN2A, resulting in upregulation of UBXN2A in the cytoplasm, where UBXN2A binds and inhibits the oncoprotein mortalin-2 (mot-2). VTD-treated cancer cells undergo cell death in UBXN2A- and mot-2-dependent manners. The cytotoxic function of VTD is grade-dependent, and the combined treatment with a sub-optimal dose of the standard chemotherapy, 5-Fluorouracil (5-FU) and etoposide, demonstrated a synergistic effect, resulting in higher therapeutic efficacy. VTD influences the CD44+ stem cells, possibly through UBXN2A-dependent inhibition of mot-2. The VTD-dependent expression of UBXN2A is a potential candidate for designing novel strategies for colon cancer treatment because: 1) In 50% of colon cancer patients, UBXN2A protein levels in tumor tissues are significantly lower than those in the adjacent normal tissues. 2) Cytoplasmic expression of the mot-2 protein is very low in non-cancerous cells; thus, VTD can produce tumor-specific toxicity while normal cells remain intact. 3) Finally, VTD or its modified analogs offer a valuable adjuvant chemotherapy strategy to improve the efficacy of 5-FU-based chemotherapy for colon cancer patients harboring WT-p53. PMID:26188124

  13. Discovery of a small-molecule binder of the oncoprotein gankyrin that modulates gankyrin activity in the cell

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Anasuya; O’Connor, Cornelius J.; Zhang, Fengzhi; Galvagnion, Celine; Galloway, Warren R. J. D.; Tan, Yaw Sing; Stokes, Jamie E.; Rahman, Taufiq; Verma, Chandra; Spring, David R.; Itzhaki, Laura S.

    2016-04-01

    Gankyrin is an ankyrin-repeat oncoprotein whose overexpression has been implicated in the development of many cancer types. Elevated gankyrin levels are linked to aberrant cellular events including enhanced degradation of tumour suppressor protein p53, and inhibition of gankyrin activity has therefore been identified as an attractive anticancer strategy. Gankyrin interacts with several partner proteins, and a number of these protein-protein interactions (PPIs) are of relevance to cancer. Thus, molecules that bind the PPI interface of gankyrin and interrupt these interactions are of considerable interest. Herein, we report the discovery of a small molecule termed cjoc42 that is capable of binding to gankyrin. Cell-based experiments demonstrate that cjoc42 can inhibit gankyrin activity in a dose-dependent manner: cjoc42 prevents the decrease in p53 protein levels normally associated with high amounts of gankyrin, and it restores p53-dependent transcription and sensitivity to DNA damage. The results represent the first evidence that gankyrin is a “druggable” target with small molecules.

  14. HPV oncoprotein E6 is a structure-dependent DNA-binding protein that recognizes four-way junctions.

    PubMed

    Ristriani, T; Masson, M; Nominé, Y; Laurent, C; Lefevre, J F; Weiss, E; Travé, G

    2000-03-10

    E6 is an oncoprotein implicated in cervical cancers, produced by "high-risk" human papillomaviruses. E6 is thought to promote tumorigenesis by stimulating cellular degradation of the tumour suppressor p53, but it might display other activities. Sequence similarity was recently detected between E6 and endonuclease VII, a protein of phage T4 that recognizes and cleaves four-way DNA junctions. Here, we purified recombinant E6 proteins and demonstrated that high-risk E6 s bind selectively to four-way junctions in a structure-dependent manner. Several residues in the C-terminal zinc-binding domain, the region of E6 similar to endonuclease VII, are necessary for the junction-binding activity. E6 binds to the junction as a monomer. Comparative electrophoresis shows that E6-bound junctions migrate in an extended square conformation. Magnesium inhibits the electrophoretic migration of the complexes but does not seem to influence their formation at equilibrium. This work is the first demonstration of specific binding of purified active E6 to a well-characterized DNA ligand, and suggests new modes of action of E6 in oncogenesis. PMID:10698626

  15. The role of oncoprotein NM23 gene from Exopalaemon carinicauda is response to pathogens challenge and ammonia-N stress.

    PubMed

    Duan, Yafei; Li, Jitao; Zhang, Zhe; Li, Jian; Ge, Qianqian; Liu, Ping

    2015-12-01

    Oncoprotein NM23, as a family of genes encoding the nucleoside diphosphate (NDP) kinase, plays important roles in bioenergetics, DNA replication, differentiation and tumor metastasis. In this study, a full-length cDNA of NM23 (designated EcNM23) was cloned from Exopalaemon carinicauda by using rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of EcNM23 was 755 bp, which contains an open reading frame (ORF) of 518 bp, encoding a 175 amino-acid polypeptide with the predicted molecular weight of 19.60 kDa and estimated isoelectric point of 7.67. The deduced amino acid sequence of EcNM23 shared high identity (86%-93%) with that of other crustaceans. a NDP kinase super family signature was identified in E. carinicauda EcNM23. Quantitative real-time RT-qPCR analysis indicated that EcNM23 was expressed in all the examined tissues with the high expression level in hemocytes and ovary. The EcNM23 expression in immune-related tissues changed rapidly and reached peak at different time after pathogens (Vibrio parahaemolyticus and WSSV) challenge and ammonia-N stress treatment. The results suggested that EcNM23 might be associated with the immune defenses to pathogens infection and ammonia-N stress in E. carinicauda. PMID:26314522

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

    PubMed Central

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

    2014-01-01

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

  17. Control of microtubule dynamics by oncoprotein 18: dissection of the regulatory role of multisite phosphorylation during mitosis.

    PubMed Central

    Larsson, N; Marklund, U; Gradin, H M; Brattsand, G; Gullberg, M

    1997-01-01

    Oncoprotein 18 (Op18; also termed p19, 19K, metablastin, stathmin, and prosolin) is a conserved protein that regulates microtubule (MT) dynamics. Op18 is multisite phosphorylated on four Ser residues during mitosis; two of these Ser residues, Ser-25 and Ser-38, are targets for cyclin-dependent protein kinases (CDKs), and the other two Ser residues, Ser-16 and Ser-63, are targets for an unidentified protein kinase. Mutations of the two CDK sites have recently been shown to result in a mitotic block caused by destabilization of MTs. To understand the role of Op18 in regulation of MT dynamics during mitosis, in this study we dissected the functions of all four phosphorylation sites of Op18 by combining genetic, morphological, and biochemical analyses. The data show that all four phosphorylation sites are involved in switching off Op18 activity during mitosis, an event that appears to be essential for formation of the spindle during metaphase. However, the mechanisms by which specific sites down-regulate Op18 activity differ. Hence, dual phosphorylation on the CDK sites Ser-25 and Ser-38 appears to be required for phosphorylation of Ser-16 and Ser-63; however, by themselves, the CDK sites are of only minor importance in direct regulation of Op18 activity. Subsequent phosphorylation of either Ser-16, Ser-63, or both efficiently switches off Op18 activity. PMID:9271428

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

    PubMed

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

    2014-07-15

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

  19. The E5 oncoprotein of human papillomavirus type 16 inhibits the acidification of endosomes in human keratinocytes.

    PubMed Central

    Straight, S W; Herman, B; McCance, D J

    1995-01-01

    The human papillomavirus type 16 E5 oncoprotein possesses mitogenic activity that acts synergistically with epidermal growth factor (EGF) in human keratinocytes and inhibits the degradation of the EGF receptor in endosomal compartments after ligand-stimulated endocytosis. One potential explanation for these observations is that E5 inhibits the acidification of endosomes. This may be mediated through the 16-kDa component of the vacuolar proton-ATPase, since animal and human papillomavirus E5 proteins bind this subunit protein. Using a ratio-imaging technique to determine endosomal pH, we found that the acidification of endosomes in E5-expressing keratinocytes was delayed at least fourfold compared with normal human keratinocytes and endosomes in some cells never completely acidified. Furthermore, E5 expression increased the resistance of keratinocytes to protein synthesis inhibition by diphtheria toxin, a process dependent on efficient endosomal acidification. Finally, artificially inhibiting endosomal acidification with chloroquine during the endocytosis of EGF receptors in keratinocytes demonstrated many of the same effects as the expression of human papillomavirus type 16 E5, including prolonged retention of undegraded EGF receptors in intracellular vesicles. PMID:7707548

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

    PubMed Central

    Harry, J B; Wettstein, F O

    1996-01-01

    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

  1. Interaction of Marek's Disease Virus (MDV) Oncoprotein Meq with Host Proteins: A Proteomic Approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s Disease is a T cell lymphoma disease of chicken induced by an oncogenic, cell associated alpha herpes virus. Oncogenicity in the Marek’s disease is mostly attributed to a transcription factor termed as Meq. To understand the mechanisms of oncogenicity of Meq, it is necessary to understand it...

  2. Activation of dendritic cells and induction of T cell responses by HPV 16 L1/E7 chimeric virus-like particles are enhanced by CpG ODN or sorbitol.

    PubMed

    Freyschmidt, Eva-Jasmin; Alonso, Angel; Hartmann, Gunther; Gissmann, Lutz

    2004-08-01

    Chimeric human papillomavirus-like particles, consisting of human papillomavirus (HPV) 16 L1-E7 fusion proteins [HPV 16 L1/E7 chimeric virus-like particles (CVLP)], are a vaccine candidate for treatment and prevention of cervical cancer. Although in preclinical studies CVLPs were shown to induce neutralizing antibodies and L1- and E7-specific T cell responses, the results of a recent clinical trial emphasized the need of improved immunogenicity of CVLPs. Here we studied the interaction of HPV 16 L1/E7 CVLPs with mouse bone marrow-derived dendritic cells (BMDCs) activated with different immune adjuvants. We found that lipopolysaccharides (LPS), unmethylated CpG motifs (CpG ODN) and sorbitol enhanced CVLP-induced stimulation of C57BL/6 mouse BMDCs as revealed by increased levels of CD40, CD80, MHC II and CD54 at the cell surface. CpG ODN and sorbitol also enhanced the presentation of Db-restricted cytotoxic T lymphocyte epitopes to HPV 16 L1- or E7-specific T lymphocytes after loading of CVLPs onto BMDCs. Treatment of BMDCs with CpG ODN in combination with CVLPs improved in vitro priming of naive T lymphocytes by CVLP-loaded BMDCs. In vivo, CVLP-loaded BMDCs were more immunogenic as compared with injection of CVLPs alone. CpG ODN and sorbitol further enhanced priming of antigen-specific T cell responses. Our data demonstrate that CpG ODN- or sorbitol-activated BMDCs substantially increase the immunogenicity of CVLPs. Implementing our results in clinical trial protocols may lead to improved activity of therapeutic HPV vaccines for the treatment of HPV-induced cancer. PMID:15456078

  3. A Synthetic E7 Gene of Human Papillomavirus Type 16 That Yields Enhanced Expression of the Protein in Mammalian Cells and Is Useful for DNA Immunization Studies

    PubMed Central

    Cid-Arregui, Angel; Juárez, Victoria; Hausen, Harald zur

    2003-01-01

    A synthetic E7 gene of human papillomavirus (HPV) type 16 was generated that consists entirely of preferred human codons. Expression analysis of the synthetic E7 gene in human and animal cells showed levels of E7 protein 20- to 100-fold higher than those obtained with wild-type E7. Enhanced expression of E7 protein resulted from highly efficient translation, as well as increased stability of the E7 mRNA due to its codon optimization. Higher levels of E7 protein in cells transfected with synthetic E7 correlated with significant loss of cell viability in various human cell lines. In contrast, lower E7 protein expression driven by the wild-type gene resulted in a slight induction of cell proliferation. Furthermore, mice inoculated with plasmids expressing the synthetic E7 gene produced significantly higher levels of E7 antibodies than littermates injected with wild-type E7, suggesting that synthetic E7 may be useful for DNA immunization studies and the development of genetic vaccines against HPV-16. In view of these results, we hypothesize that HPVs may have retained a pattern of G + C content and codon usage distinct from that of their host cells in response to selective pressure. Thus, the nonhuman codon bias may have been conserved by HPVs to prevent compromising viability of the host cells by excessive viral early protein expression, as well as to evade the immune system. PMID:12663798

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

    SciTech Connect

    Hayakawa, Kazuo; Ikeya, Makoto; Fukuta, Makoto; Woltjen, Knut; Tamaki, Sakura; Takahara, Naoko; Kato, Tomohisa; Sato, Shingo; Otsuka, Takanobu; Toguchida, Junya

    2013-03-22

    Highlights: ► We tried to identify targets of synovial sarcoma (SS)-associated SYT–SSX fusion gene. ► We established pluripotent stem cell (PSC) lines with inducible SYT–SSX gene. ► SYT–SSX responsive genes were identified by the induction of SYT–SSX in PSC. ► SS-related genes were selected from database by in silico analyses. ► 51 genes were finally identified among SS-related genes as targets of SYT–SSX in PSC. -- Abstract: Synovial sarcoma (SS) is a malignant soft tissue tumor harboring chromosomal translocation t(X; 18)(p11.2; q11.2), which produces SS-specific fusion gene, SYT–SSX. Although precise function of SYT–SSX remains to be investigated, accumulating evidences suggest its role in gene regulation via epigenetic mechanisms, and the product of SYT–SSX target genes may serve as biomarkers of SS. Lack of knowledge about the cell-of-origin of SS, however, has placed obstacle in the way of target identification. Here we report a novel approach to identify SYT–SSX2 target genes using human pluripotent stem cells (hPSCs) containing a doxycycline-inducible SYT–SSX2 gene. SYT–SSX2 was efficiently induced both at mRNA and protein levels within three hours after doxycycline administration, while no morphological change of hPSCs was observed until 24 h. Serial microarray analyses identified genes of which the expression level changed more than twofold within 24 h. Surprisingly, the majority (297/312, 95.2%) were up-regulated genes and a result inconsistent with the current concept of SYT–SSX as a transcriptional repressor. Comparing these genes with SS-related genes which were selected by a series of in silico analyses, 49 and 2 genes were finally identified as candidates of up- and down-regulated target of SYT–SSX, respectively. Association of these genes with SYT–SSX in SS cells was confirmed by knockdown experiments. Expression profiles of SS-related genes in hPSCs and human mesenchymal stem cells (hMSCs) were strikingly

  5. TARGETING THE MUC1-C ONCOPROTEIN DOWNREGULATES HER2 ACTIVATION AND ABROGATES TRASTUZUMAB RESISTANCE IN BREAST CANCER CELLS

    PubMed Central

    Raina, Deepak; Uchida, Yasumitsu; Kharbanda, Akriti; Rajabi, Hasan; Panchamoorthy, Govind; Jin, Caining; Kharbanda, Surender; Scaltriti, Maurizio; Baselga, Jose; Kufe, Donald

    2014-01-01

    Patients with HER2 positive breast cancer often exhibit intrinsic or acquired resistance to trastuzumab treatment. The transmembrane MUC1-C oncoprotein is aberrantly overexpressed in breast cancer cells and associates with HER2. The present studies demonstrate that silencing MUC1-C in HER2-overexpressing SKBR3 and BT474 breast cancer cells results in downregulation of constitutive HER2 activation. Moreover, treatment with the MUC1-C inhibitor, GO-203, was associated with disruption of MUC1-C/HER2 complexes and decreases in tyrosine phosphorylated HER2 (p-HER2) levels. In studies of trastuzumab-resistant SKBR3R and BT474R cells, we found that the association between MUC1-C and HER2 is markedly increased (~20-fold) as compared to that in sensitive cells. Additionally, silencing MUC1-C in the trastuzumab-resistant cells or treatment with GO-203 decreased p-HER2 and AKT activation. Moreover, targeting MUC1-C was associated with downregulation of phospho-p27 and cyclin E, which confer trastuzumab resistance. Consistent with these results, targeting MUC1-C inhibited the growth and clonogenic survival of both trastuzumab-resistant cells. Our results further demonstrate that silencing MUC1-C reverses resistance to trastuzumab and that the combination of GO-203 and trastuzumab is highly synergistic. These findings indicate that MUC1-C contributes to constitutive activation of the HER2 pathway and that targeting MUC1-C represents a potential approach to abrogate trastuzumab resistance. PMID:23912457

  6. Stringy KLT relations, global symmetries, and E 7(7)-violation

    NASA Astrophysics Data System (ADS)

    Elvang, Henriette; Kiermaier, Michael

    2010-10-01

    We study consequences of the Kawai-Lewellen-Tye (KLT) relations applied to tree amplitudes in toroidal compactifications of string theory to four dimensions. The closed string tree amplitudes with massless external states respect a global SU(4) × SU(4) symmetry, which is enhanced to the SU(8) R -symmetry of mathcal{N} = 8 supergravity in the field theory limit. Our analysis focuses on two aspects: (i) We provide a detailed account of the simplest SU(8)-violating amplitudes. We classify these processes and derive explicit superamplitudes for all local 5-and 6-point operators with SU(4) × SU(4) symmetry at order α'3 . Their origin is the dilatonic operator e-6φ R 4 in the closed-string effective action. (ii) We expand the 6-point closed string tree amplitudes to order α3 and use two different methods to isolate the SU(8)-singlet contribution from e-6φ R 4. This allows us to extract the matrix elements of the unique SU(8)-invariant supersymmetrization of R 4. Their single-soft scalar limits are non-vanishing. This demonstrates that the mathcal{N} = 8 supergravity candidate counterterm R 4 is incompatible with continuous E 7(7) symmetry. From the soft scalar limits, we reconstruct to quadratic order the SU(8)-invariant function of scalars that multiplies R 4, and show that it satisfies the Laplace eigenvalue equation derived recently from supersymmetry and duality constraints.

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

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

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

    SciTech Connect

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

    2011-08-26

    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

  9. Frequency of antibodies against E4 and E7 from human papillomavirus type 16 in Mexican soldiers.

    PubMed

    Plett-Torres, T; Cruz-Valdez, A; Esquivel-Guadarrama, F; Hernández-Nevarez, P; Lazcano-Ponce, E; Gutiérrez-Xicotencatl, L

    2007-01-01

    The high prevalence of HPV in men's genitalia and the low frequency of virus-associated lesions gave rise to questions on the influence of infection-site on the HPV antibody profile. In a cross-sectional study, HPV infection in penis and urethra, and serum antibodies against HPV-16 E4 and E7 proteins were evaluated in 288 Mexican soldiers. The results showed that HPV prevalence was 31% (51% in penis, 11% in urethra and 38% in both sites), while 47% were multiple infections. Overall, seroprevalence was 13% for anti-E4 antibodies and 6% for anti-E7. However, the highest prevalence of anti-E4 antibodies was observed in men with HPV infection in urethra (30%), while for E7 antibodies, the highest prevalence (10%) was found in men who tested positive for HPV in penis. The prevalence of IgG and IgA anti-E4 was related to HPV-16 urethral infection, while detection of HPV-16 in penis was related to IgG anti-E7 prevalence. In conclusion, the high-risk sexual behavior observed in this population might be responsible for high HPV prevalence and multiple infections. However, the seroprevalence of E4 and E7 was similar to that observed in healthy Mexican women. These results suggest that the humoral immune response against HPV infection in men differs, depending on the site of infection. PMID:16896549

  10. Identification of T- and B-cell epitopes of the E7 protein of human papillomavirus type 16.

    PubMed Central

    Comerford, S A; McCance, D J; Dougan, G; Tite, J P

    1991-01-01

    There is strong evidence implicating human papillomavirus type 16 (HPV16) in the genesis of human genital cancer. Viral DNA has been identified in invasive carcinoma of the uterine cervix and in cell lines derived from cervical carcinomas. These sequences are actively transcribed, and translation products corresponding to the early (E)-region genes have been identified. The most abundant viral protein is the E7 protein, which has been shown to possess transforming activity for both established and primary cells. In addition, it has been shown to bind to a cellular tumor suppressor, the retinoblastoma gene product (pRb-105). In view of these properties, we have undertaken the immunological analysis of this protein and have identified four T-cell epitopes and three B-cell epitopes by using a series of overlapping peptides spanning the entire HPV16 E7 sequence. Two of the B-cell epitopes were recognized by antisera from mice with three different murine (H-2) haplotypes (k, d, and s) immunized with two different E7 fusion proteins and from Fischer rats seeded with baby rat kidney cells transformed by HPV16 E7 and ras. A third B-cell epitope was recognized by antisera from CBA mice seeded with HPV16 E7-expressing L cells. Two regions of the protein contain common B- and T-cell epitopes, one of which appears to be particularly immunodominant. Images PMID:1714516