Elizabeth Payne
Publications
-
9.43Impact points
Both treated and untreated tumors are eliminated by short hairpin RNA-based induction of target-specific immune responses.
Proceedings of the National Academy of Sciences of the United States of America. 06/2009; 106(20):8314-9.
RNA interference (RNAi) for cancer treatment relies on the ability to directly kill cancer cells via down-regulation of target genes, but issues of delivery and efficacy have limited clinical adoption. Furthermore, current studies using immune-deficient animal models disregard potential interactions... [more] RNA interference (RNAi) for cancer treatment relies on the ability to directly kill cancer cells via down-regulation of target genes, but issues of delivery and efficacy have limited clinical adoption. Furthermore, current studies using immune-deficient animal models disregard potential interactions with the adaptive immune system. It has previously been observed that certain viral antigens appear to be more rapidly presented to the immune system than normal proteins due to the production of defective ribosomal products by the virus. Given that RNAi could potentially result in the generation of truncated mRNAs, we wondered whether a similar mechanism of immune presentation of a target gene was possible. Here we show that RNAi-cleaved mRNAs can be translated into incomplete protein, and if cleavage was downstream of cytotoxic T cell epitopes, resulted in increased presentation of target protein and the generation of a tumor-protective immune response. We show that mice inoculated with tumor cells treated with such short hairpin RNAs (shRNAs) were protected from subsequent challenge with untreated tumors. However, protection was only found if shRNAs were targeted downstream of the dominant cytotoxic T cell (CTL) epitope. Our work suggests that RNAi can alter immunity to targets and shows that not all tumor cells require direct RNAi exposure for treatment to be effective in vivo, pointing the way to a new class of RNAi-based therapy.
-
1.63Impact points
The human papillomavirus type 16 E7 protein binds human interferon regulatory factor-9 via a novel PEST domain required for transformation.
Journal of interferon & cytokine research : the official journal of the International Society for Interferon and Cytokine Research. 08/2006; 26(7):455-61.
It is critical that viruses are able to avoid the antiviral activities of interferon (IFN). We have shown previously that the human papillomavirus (HPV) is able to avoid IFN-alpha via interaction of the HPV-16 E7 protein with IFN regulatory factor-9 (IRF-9). Here, we investigated the details of the ... [more] It is critical that viruses are able to avoid the antiviral activities of interferon (IFN). We have shown previously that the human papillomavirus (HPV) is able to avoid IFN-alpha via interaction of the HPV-16 E7 protein with IFN regulatory factor-9 (IRF-9). Here, we investigated the details of the interaction using HPV-16 E7 peptide mapping to show that IRF-9 binds HPV-16 E7 in a domain encompassing amino acids 25-36. A closer examination of this region indicates this is a novel proline, glutamate, serine, and threonine-rich (PEST) domain, with a PEST score of 8.74. We have also mapped the region of interaction within IRF-9 and found that amino acids 354-393 play an important role in binding to HPV-16 E7. This region of IRF-9 encompasses the IRF association domain (IAD), a region important for protein-protein interaction central to IRF function. Finally, we used alanine-scanning mutagenesis to determine if E7-IRF-9 interaction was important for E7-mediated cellular transformation and found that the HPV-16 E7 mutants Y25A, E26A, S31A, S32A, and E35A, but not L28A and N29A, caused loss of transformation ability. Preliminary data suggest loss of IRF-9 interaction with E7 mutants correlated with transformation. Our work suggests E7-IRF-9 interaction is important for the transforming ability of HPV-16 E7 and that HPV-16 E7 may interact with other IRF proteins that have IAD domains.
-
1.63Impact points
A novel method for screening viral interferon-resistance genes.
Journal of interferon & cytokine research : the official journal of the International Society for Interferon and Cytokine Research. 09/2004; 24(8):470-7.
Many viruses have evolved mechanisms to antagonize the interferon (IFN) system, targeting all the major components involved in receptor binding and signaling. Although a number of these vital proteins are homologous to cellular proteins involved in IFN downregulation (e.g., viral IFN regulatory fact... [more] Many viruses have evolved mechanisms to antagonize the interferon (IFN) system, targeting all the major components involved in receptor binding and signaling. Although a number of these vital proteins are homologous to cellular proteins involved in IFN downregulation (e.g., viral IFN regulatory factors [vIRFs]), many share little resemblance to known proteins. To determine the IFN-blocking properties of these proteins, functional assays are required. Here, we present a new and rapid functional screening method, based on the 2fTGH cell line, which is able to determine viral gene products that inhibit the IFN-alpha/Jak-Stat signaling pathway. Expression cloning of viral IFN-blocking genes into 2fTGH and consequent selection with IFN-alpha and 6-thioguanine result in the outgrowth of cells that are no longer responsive to IFN-alpha. We also demonstrate that selection occurs if members of the Jak-Stat signaling pathway are lost. To show the utility of our system, we have used a known suppressor of IFN signaling, the human papillomavirus (HPV) E7 gene. Expression of E7 causes the loss of ability of 2fTGH cells to respond to IFN-alpha treatment because of a functional disruption of the signaling pathway. This approach offers a new strategy for identifying novel viral genes or new functions of already described viral genes that have a role in IFN-alpha signaling inhibition.
-
Expression of the α6 Integrin Confers Papillomavirus Binding upon Receptor-Negative B-Cells
Virology.
Papillomaviruses (PV) bind to a wide range of cell lines in a specific and saturable manner. We have recently identified a candidate receptor for papillomavirus as the α6 integrin (Evander et al., J. Virol. 71, 2449–2456, 1997). We have further investigated the role the α6 integrin plays in PV bindi... [more] Papillomaviruses (PV) bind to a wide range of cell lines in a specific and saturable manner. We have recently identified a candidate receptor for papillomavirus as the α6 integrin (Evander et al., J. Virol. 71, 2449–2456, 1997). We have further investigated the role the α6 integrin plays in PV binding. Here we show that the cells expressing the α6 integrin, partnered with either the β4 integrin or the β1 integrin, are equally able to bind PV HPV6b L1 virus-like particles, indicating that the beta partner does not play a major role in virus binding. In order to provide definitive evidence that the α6 integrin is required for PV binding we undertook to genetically complement the receptor-negative B-cell line DG75 by expressing the human α6A gene. The transduction of the α6 integrin gene into DG75 cells results in the cell surface expression of the α6 protein and this expression confers upon DG75 cells the ability to bind laminin, a normal ligand for α6 integrin. Furthermore, the α6 protein is partnered with the β1 integrin in DG75 cells. Finally, we show that the DG75-α6 cells were able to bind papillomavirus VLPs and this binding was inhibited by a functionally blocking anti-α6 antibody. Together these data indicate that the α6 integrin is a primary cell receptor for papillomaviruses and is both necessary and sufficient for PV binding.
-
The Human Papillomavirus E7 Protein Is Able to Inhibit the Antiviral and Anti-growth Functions of Interferon-α
Virology.
It is now well recognized that cervical cancer is caused by infection with certain human papillomavirus (HPV) subtypes and while interferon-α (IFN-α) is used to treat HPV-infected lesions, HPV appears to have developed a means to avoid the effects of IFN-α. Clinically, resistance appears to be assoc... [more] It is now well recognized that cervical cancer is caused by infection with certain human papillomavirus (HPV) subtypes and while interferon-α (IFN-α) is used to treat HPV-infected lesions, HPV appears to have developed a means to avoid the effects of IFN-α. Clinically, resistance appears to be associated with the expression of the E7 oncoprotein. Here we investigated the effects of expression in cells of the E7 protein from high- and low-risk papillomavirus subtypes on a range of responses to IFN-α. 2fTGH, a cell line dependent on IFN-α for growth in selection medium, grew significantly less well in the presence of E7, and the antiproliferative effects of IFN-α upon epithelial cells was lost upon E7 expression. The antiviral effects of IFN-α were abrogated in E7-expressing cells. Loss of response to IFN-α was found to occur in both high- and low-risk papillomaviruses. Finally, deletion of amino acids 21–24 of HPV type 16 E7 protein partially reversed repression. We conclude that E7 inhibits the functional effects of IFN-α and that this property is shared by all HPV subtypes tested.
-
Expression of the alpha 6 integrin confers papillomavirus binding upon receptor-negative B-cells
Papillomaviruses (PV) bind to a wide range of cell lines in a specific and saturable manner. We have recently identified a candidate receptor for papillomavirus as the alpha 6 integrin (Evander at al., J. Virol. 71, 2449-2456, 1997). We have further investigated the role the a6 integrin plays in PV ... [more] Papillomaviruses (PV) bind to a wide range of cell lines in a specific and saturable manner. We have recently identified a candidate receptor for papillomavirus as the alpha 6 integrin (Evander at al., J. Virol. 71, 2449-2456, 1997). We have further investigated the role the a6 integrin plays in PV binding. Here we show that the cells expressing the alpha 6 integrin, partnered with either the beta 4 integrin or the beta 1 integrin, are equally able to bind PV H PV6b L1 virus-like particles, indicating that the beta partner does not play a major role in virus binding. In order to provide definitive evidence that the alpha 6 integrin is required for PV binding we undertook to genetically complement the receptor-negative B-cell line DG75 by expressing the human alpha 6A gene. The transduction of the alpha 6 integrin gene into DG75 cells results in the cell surface expression of the alpha 6 protein and this expression confers upon DG75 cells the ability to bind laminin, a normal ligand for alpha 6 integrin. Furthermore, the alpha 6 protein is partnered with the beta 1 integrin in DG75 cells. Finally, we show that the DG75-alpha 6 cells were able to bind papillomavirus VLPs and this binding was inhibited by a functionally blocking anti-alpha 6 antibody. Together these data indicate that the alpha 6 integrin is a primary cell receptor for papillomaviruses and is both necessary and sufficient for PV binding. (C) 1999 Academic Press.
-
The human papillomavirus E7 protein is able to inhibit the antiviral and anti-growth functions of interferon-alpha
It is now well recognized that cervical cancer is caused by infection with certain human papillomavirus (HPV) subtypes and while interferon-alpha (IFN-alpha) is used to treat HPV-infected lesions, HPV appears to have developed a means to avoid the effects of IFN-alpha. Clinically, resistance appears... [more] It is now well recognized that cervical cancer is caused by infection with certain human papillomavirus (HPV) subtypes and while interferon-alpha (IFN-alpha) is used to treat HPV-infected lesions, HPV appears to have developed a means to avoid the effects of IFN-alpha. Clinically, resistance appears to be associated with the expression of the E7 oncoprotein. Here we investigated the effects of expression in cells of the E7 protein from high- and low-risk papillomavirus subtypes on a range of responses to IFN-alpha. 2fTGH, a cell line dependent on IFN-alpha for growth in selection medium, grew significantly less well in the presence of E7, and the antiproliferative effects of IFN-alpha upon epithelial cells was lost upon E7 expression. The antiviral effects of IFN-alpha were abrogated in E7-expressing cells. Loss of response to IFN-alpha was found to occur in both high- and low-risk papillomaviruses. Finally, deletion of amino acids 21-24 of HPV type 16 E7 protein partially reversed repression. We conclude that E7 inhibits the functional effects of IFN-alpha and that this property is shared by all HPV subtypes tested. (C) 2000 Academic Press.
Following (2)
-
Fang Zhou
3rd People's Hospital of Shen Zhen -
Annika Antonsson
Queensland Institute of Medical Research
