John Hiscott, Ph.D., an internationally recognized molecular biologist and virologist, is a program director and a principal investigator and full member of the Vaccine and Gene Therapy Institute of Florida (VGTI Florida®). Dr. Hiscott earned his doctorate in medical sciences from New York University Medical Center, and completed post-doctoral training at the Roche Institute in New Jersey, and the Institute for Molecular Biology at the University of Zurich in Switzerland. Prior to joining VGTI Florida, he was Professor of Medicine and Microbiology in Montreal, and Director of the Molecular Oncology Group at Jewish General Hospital. Dr. Hiscott’s research has provided major contributions to the understanding of the immune response to infectious diseases, cancer and human retrovirus pathogenesis. He is also investigating the use of oncolytic vaccine vectors as novel experimental cancer therapeutics. Dr. Hiscott has published more than 230 peer-review biomedical research articles and reviews in prestigious international journals, such as Science, Nature Immunology, Cell Host & Microbe, Cancer Research, and Proceedings of the National Academy of Sciences USA.
1. Molecular interactions regulating antiviral and inflammatory response
The innate immune response constitutes the first line of defense against invading viruses and relies on numerous pattern recognition receptors (PRR) for detection of infection. Several families of immune receptors have been described; Toll-like receptors (TLR), RIG-like receptors (RLR), Nod-like receptors (NLR) and Aim2-like receptors (ALR) interact with diverse viral components and provoke an immune response. Recognition of non-self molecular structures or aberrant localization of antigenic molecules is the first step in the generation of an effective immune response, and leads to the activation of multiple signaling cascades that stimulate both antiviral and inflammatory responses. These early events result in the disruption of viral replication and the mobilization of the adaptive arm of the immune system.
Central to the host antiviral response is the production of Type I interferons (IFNs), a large family of multifunctional immunoregulatory proteins. Co-ordinate downstream activation of both TLR- and RIG-I-dependent pathways induces divergent signals at the level of kinase activity – with IKK?/IKK??promoting activation of NF-?B and inflammatory cytokine production, and TBK1/IKK? driving the antiviral arm of innate immunity via IRF3 and IRF7 stimulation (Figure 1). Previous research from this laboratory has provided contributions to the paradigm of antiviral gene regulation, involving primary induction of interferon expression through the combined activities of IRF-3 and NF-?B, and secondary amplification of the response via IRF-7 stimulation of the antiviral transcriptional program. These studies subsequently identified TBK1/IKKepsilon as the virus-activated kinase (VAK) activities that target IRF-3 and IRF-7 for phosphorylation, thus functionally linking the NF-?B and IRF pathways in the development of the antiviral response. Since that time, IRF-3 and IRF-7, as well as the IKK-related kinases, have become firmly integrated within the TLR- and RIG-I dependent pathways of the innate immune response to viral pathogens.
The innate immune system also closely interacts with basic cellular processes such as apoptosis, autophagy and reactive oxygen species production. We are dissecting the molecular interactions and the cellular processes that activate antiviral signaling in response to dengue and influenza virus infections, both major global pathogens.
2. Antiviral immune response to dengue virus infection
Dengue virus, the causative agent of Dengue Fever, represents a major global health concern for which no effective antiviral drug or vaccine exists. As such, there is an urgent need to understand dengue pathogenesis and the immune response to infection, to facilitate the discovery of novel therapeutics. The vast majority of infected individuals develop a self-limiting Dengue Fever, but approximately 500,000 clinical cases result in more severe manifestations, such as Dengue Hemmorrhagic Fever and Dengue Shock Syndrome (DHF/DSS) resulting in 24,000 deaths per year. One of the strongest associations between infection and severity of disease is the presence of anti-DenV antibodies from previous dengue virus infections, resulting in an antibody-dependent enhancement (ADE) of infection. Specific host responses to infection can predict disease severity and alterations in gene expression patterns in peripheral blood from DenV-infected patients correlate with dengue disease severity - in particular, with gene networks belonging to the antiviral, inflammasome, and complement pathways.
The major goals of this project are to understand the mechanisms by which Dengue virus infection and ADE modulate the host antiviral and inflammatory response during de novo infection in order to propose alternative therapeutic strategies.
3. Development of oncolytic vaccines for cancer treatment
An ideal cancer therapeutic will selectively kill malignant cells using a multi-pronged approach, while leaving normal tissues intact. The current standards of cancer care – surgery, chemotherapy and radiation therapy - often fall short of this goal. Thus, it is imperative to explore new knowledge of the molecular biology of cancer to design new therapies that will specifically target cancer cells. Several new avenues of research have moved to pre-clinical and clinical trials with the design of novel biotherapeutics such as monoclonal antibodies, immunotherapies and oncolytic viruses (OVs). These strategies selectively exploit genetic defects commonly found in tumor cells and represent promising new treatments for a range of human cancers.
Oncolytic Viruses (OV) are versatile therapeutics (Figure 2) that have recently attracted significant attention in light of the promising results of several clinical trials. These multifunctional therapeutics can be genetically engineered to specifically target into and kill cancer cells by exploiting genetic abnormalities (including defects in cell division, innate immune response, and gene expression) of tumor cells. Not only do OV specifically target tumor cells, but they are non-pathogenic, and can stimulate production of cytokines and elicit anti-tumor immune responses as well. Overall, OV have potential as effective therapeutics for cancer treatment with fewer side effects than commonly seen with other treatments. The major goals of this project are to evaluate the efficacy of OV in treatment of therapy-resistant tumors, to examine the combination of OV with histone deacetylase inhibitors (HDIs) in pre-clinical models of prostate cancer, and to understand how stress response mechanisms affect viral oncolysis.
We previously networked together as an NCI-sponsored Oncolytic Virus Consortium (COVCo), a team of clinicians and scientists, dedicated to developing novel oncolytic virus therapeutics. Candidate viruses at all stages of development are being studied, with the goal to combine scientific and clinical expertise to foster the generation of new therapeutics and clinical approaches. In this project, we are investigating the synergism between the histone deacetylase inhibitor vorinostat (SAHA) and the oncolytic Vesicular Stomatitis Virus (VSV) in the treatment of prostate cancer, using human prostate cancer cells and primary human prostate tumor specimens.
Vladimir Beljanski – Research Associate
Vladimir Beljanski received his Ph.D. from Emory University, Atlanta where he developed models for studying combination therapies in cancer treatment. His Postdoctoral training was completed at the Medical University of South Carolina where he worked on a pre-clinical development of a kinase inhibitor. In Dr Hiscott’s lab he is studying antitumor activity of vesicular stomatitis virus in prostate and lung tumor models. He is currently examining the genes responsible for the potentiation of VSV oncolytic activity by activation of the NF-?B signaling pathway. Another research interest is the role of ER stress response in the regulation of VSV oncolysis.
Cindy Chiang – Postdoctoral Research Fellow
Cindy Chiang received her M.S. and Ph.D. from Florida Atlantic University, Boca Raton. During this time her research focused on the gene regulation of the SNAG family of transcription factors. She studied DNA and protein interactions to identify target genes and co-repressors of these regulatory molecules. She joined the Hiscott Lab as a Postdoctoral Research Fellow in 2012. Her current research project involves the development of enhanced recombinant VSV vectors with the potential to deliver therapeutic molecules to specifically target and kill cancer cells, via enhanced anti-tumor immune mechanisms.
Carmen N. Nichols – Research Associate
Carmen Nichols obtained her Ph.D. in Molecular Virology from The University of Reading, UK. She completed her Postdoctoral training at the Lindsley F. Kimball Research Institute (NYBC), New York and at Thomas Jefferson University, Philadelphia. Her research in the Hiscott Lab seeks to elucidate differential signaling events involved in the regulation of innate immune and antiviral responses in de novo Dengue virus of primary myeloid cells. Her aim is to utilize single-cell, high-throughput gene expression studies to better understand the phenomenon of antibody dependent enhancement.
David Olagnier – Postdoctoral Research Fellow
David Olagnier graduated from Toulouse University, France in 2011. His Ph.D. focused on the study of pathways controlling macrophage polarization and their anti-infectious functions. He expanded the study to the innate immune response against parasites and fungi, specifically to the signaling pathways controlling the expression of phagocytic receptors. He joined the Hiscott Lab in 2012 as a Postdoctoral Research Fellow and is working on dissecting the early events involved in the host response to Dengue virus infection in primary Dendritic Cells. The major objective of his project is to understand signaling cascades that regulate the host antiviral response to infection and to develop small molecules to trigger antiviral pathways that intrinsically combat infection.
SELECTED PUBLICATIONS (from 230 peer-reviewed publications)
Regulation of the innate antiviral response
1. Sharma S, tenOever B, Grandvaux N, Zhou G, Lin R, Hiscott J. Triggering the interferon antiviral response through an IKK-related pathway. Science 300: 1148-1151 (2003).
2. tenOever B, Sharma S, Zou W, Sun Q, Grandvaux N, Julkunen I, Akira S, Yeh W, Lin R, Hiscott J. Activation of TBK1 and IKK? kinases by VSV infection J. Virol. 78: 10636-10649 (2004).
3. Romieu-Mourez R, Solis M, Nardin A, Goubau D, Baron-Bodo V, Massie B, Salcedo M, Hiscott J. Distinct roles of IRF-3 and IRF-7 in the activation of anti-tumor properties of human macrophages. Cancer Research, 66 : 10576-10585 (2006).
4. Lin R, Lacoste J, Nakhaei P, Sun Q, Paz S, Yang L, Julkunen I, Meurs E, Hiscott J. Dissociation of a MAVS/IPS/VISA/Cardif and IKKepsilon complex from the mitochondrial outer membrane by NS3/4A proteolytic cleavage. J. Virol. 80: 6072-6083 (2006).
5. Zhao TJ, Yang L, Sun Q, Arguello M, Ballard DW, Hiscott J, Lin R. The NEMO/IKK? adapter bridges NF-?B and IRF signaling pathways. Nature Immunology, 8: 592-600 (2007).
6. Nakhaei P, Mesplede T, Sun Q, Solis M, Yang L, Chuang T-H, Ware CF, Lin R, Hiscott J. The E3 Ubiquitin ligase TRIAD3A negatively regulates the RIG-I/MAVS signaling pathway by targeting TRAF3 for degradation PLoS Pathogens 5: e1000650 (2009).
7. Paz S, Vilasco M, Arguello M, Lacoste J, Nguyen L-A, Shestakova E, Bibeau-Poirier S, Servant M, Lin R, Meurs E, Hiscott J. Ubiquitin dependent recruitment of IKKepsilon to the MAVS adapter Mol. Cell. Biol. 29: 3401-3412 (2009).
8. Olière S, Hernandez E, Lézin A, Nguyen TL, Arguello M, Wilkinson P, Sekaly R, Césaire R and Hiscott J. HTLV-1 evades antiviral immunity via upregulation of SOCS1 PLoS Pathogens, 6: e1001177 (2010).
9. Paz S, Hiscott J Curtailing IRF signaling with the E3 ligase RAUL. Immunity 33:833-835 (2010).
10. Paz S, Vilasco M, Arguello M, Werden S, Lin R, Meurs E, Hiscott J. A functional C-terminal TRAF3-binding site in MAVS participates in positive and negative regulation of the IFN antiviral response. Cell Research 21: 895-910 (2011).
11. Solis M, Nakhaei P, Jalalirad M, Lacoste J, Douville R, Arguello M, Laughrea M, Hiscott J. RIG-I dependent antiviral signaling is inhibited during de novo HIV-1 infection by protease-mediated sequestration of RIG-I. J. Virol. 85: 1224-1236 (2011).
12. Nakhaei P, Q. Sun, Solis M, Mesplede T, Bonneil E, Paz S, Lin R, Hiscott J. IKK? dependent phosphorylation and degradation of X-linked inhibitor of apoptosis sensitizes cells to virus-induced apoptosis. J. Virol. 86:726-37 (2012).
13. Lei Y, Wen H, Yu Y, Taxman D, Zhang L, Widman D, Swanson K, Damania B, Moore C, Giguere P, Siderovski D, Hiscott J, Razani B, Ting JP-Y. NLRX1 and TUFM form a mitochondrial complex that regulates type 1 interferon and autophagy. Immunity 36: 933-946 (2012).
14. Olagnier D, Hiscott J. Breaking the barrier: membrane fusion as an innate immune trigger. Nature Immunol. 13:713-715 (2012).
15. Belgnaoui S, Paz S, Goulet ML, Samuel S, Sun Q, Kikkert M, Iwai K, Dikic I, Lin R, Hiscott J. Linear ubiquitination of NEMO negatively regulates the interferon antiviral response through disruption of the MAVS-TRAF3 complex. Cell Host & Microbe 12: 211-222 (2012).
16. Goulet ML, Olagnier D, Xu Z, Paz S, Arguello M, Lafferty E, Qureshi S, Sun Q, He Z, Richards S, Smith A, Wilkinson P, Cameron M, Trautmann L, Haddad E, Sekaly RP, Lin R, Hiscott J. Broad spectrum Inhibition of virus infectivity using RNA agonists of the RIG-I pathway. PLoS Pathogens 9 : e1003298 (2013).
Oncolytic virotherapy of cancer
1. Stojdl D, Lichty B, tenOever B, Knowles S, Marius R, Reynard J, Ruoso P, Poloquin L, Atkins H, Brown EG, Durbin R, Durbin J, Hiscott J, Bell JC. Oncolytic VSV strains with defects in the shutdown of innate immunity are potent systemic anti-cancer agents. Cancer Cell 4: 263-275 (2003).
2. Cesaire R, Oliere S, Sharif-Askari E, Loignon M, Lezin A, Olindo S, Panelatti G, Kazanji M, Panasci L, Hiscott J. Oncolytic activity of VSV in primary adult T cell leukemia. Oncogene 25: 349-358 (2006).
3. Oliere S, Arguello M, Mesplede T, Tumilasci V, Nakhaei P, Stojdl D, Sonenberg N, Bell J, Hiscott J. Vesicular stomatitis virus oncolysis of T lymphocytes requires cell cycle entry and translation initiation. J Virol. 82(12):5735-5749 (2008).
4. Tumilasci VF, Olière S, Nguyên TL, Shamy A, Bell J, Hiscott J. Targeting the apoptotic pathway with BCL-2 inhibitors sensitizes primary chronic lymphocytic leukemia cells to vesicular stomatitis virus-induced oncolysis. J Virol. 82:8487-8499 (2008).
5. Nguyen L-A, Abdelbary H, Arguello M, Breitbach C, Leveille S, Yasmeen A, Bismar T, Falls T, Werier J, Bell JC, Hiscott J. Chemical targeting of the innate antiviral response by histone deacetylase inhibitors renders refractory cancers sensitive to viral oncolysis Proc. Natl. Acad. Sci. 105: 14981-14986 (2008).
6. Diallo JS, Le Boeuf F, Lai F, Cox J, Vaha-Koskela M, Abdelbary H, MacTavish H, Waite K, Falls T, Wang J, Brown R, Blanchard JE, Brown ED, Kirn DH, Hiscott J, Atkins H, Lichty BD, Bell JC. A high-throughput pharmacoviral approach identifies novel oncolytic virus sensitizers. Mol Ther. 18:1123-1129 (2010).
7. Samuel S, Tumilasci VF, Oliere S, Nguyên TL, Shamy A, Bell J, Hiscott J. VSV oncolysis in combination with the BCL-2 inhibitor obatoclax overcomes apoptosis resistance in chronic lymphocytic leukemia. Mol Ther. 18:2094-103 (2010).
8. Leveille S, Samuel S, Goulet ML, Hiscott J. Enhancing VSV oncolytic activity with an improved cytosine deaminase suicide gene strategy. Cancer Gene Ther. 18:435-43 (2011).
9. Leveille S, Goulet ML, Lichty BD, Hiscott J. Vesicular stomatitis virus oncolytic treatment interferes with tumor-associated dendritic cell functions and abrogates tumor antigen presentation. J. Virol. 85:12160-12169 (2011).
10. Beljanski V, Hiscott J. The use of oncolytic viruses to overcome lung cancer drug resistance. Curr Opin Virol. 2:629-635 (2012).
11. Samuel S, Van Grevenynghe J, Beljanski V, Richards S, He Z, Nichols C, Belgnaoui SM, Steel C, Goulet ML, Shamy A, Brown D, Haddad E, Abesada G, Hiscott J. BCL-2 inhibitors sensitize chronic lymphocytic leukemia cells to vesicular stomatitis virus oncolysis by triggering autophagic and apoptotic pathways. Mol. Therapy 21: 1413-1423 (2013).