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Chakraborty S, Ye J, Wang H, Sun M, Zhang Y, Sang X, Zhuang Z. Application of toll-like receptors (TLRs) and their agonists in cancer vaccines and immunotherapy. Front Immunol 2023; 14:1227833. [PMID: 37936697 PMCID: PMC10626551 DOI: 10.3389/fimmu.2023.1227833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 10/10/2023] [Indexed: 11/09/2023] Open
Abstract
Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) expressed in various immune cell types and perform multiple purposes and duties involved in the induction of innate and adaptive immunity. Their capability to propagate immunity makes them attractive targets for the expansion of numerous immunotherapeutic approaches targeting cancer. These immunotherapeutic strategies include using TLR ligands/agonists as monotherapy or combined therapeutic strategies. Several TLR agonists have demonstrated significant efficacy in advanced clinical trials. In recent years, multiple reports established the applicability of TLR agonists as adjuvants to chemotherapeutic drugs, radiation, and immunotherapies, including cancer vaccines. Cancer vaccines are a relatively novel approach in the field of cancer immunotherapy and are currently under extensive evaluation for treating different cancers. In the present review, we tried to deliver an inclusive discussion of the significant TLR agonists and discussed their application and challenges to their incorporation into cancer immunotherapy approaches, particularly highlighting the usage of TLR agonists as functional adjuvants to cancer vaccines. Finally, we present the translational potential of rWTC-MBTA vaccination [irradiated whole tumor cells (rWTC) pulsed with phagocytic agonists Mannan-BAM, TLR ligands, and anti-CD40 agonisticAntibody], an autologous cancer vaccine leveraging membrane-bound Mannan-BAM, and the immune-inducing prowess of TLR agonists as a probable immunotherapy in multiple cancer types.
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Affiliation(s)
- Samik Chakraborty
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
- NE1 Inc., New York, NY, United States
| | - Juan Ye
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Herui Wang
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Mitchell Sun
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Yaping Zhang
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Xueyu Sang
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Zhengping Zhuang
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
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2
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Microbial-Derived Toll-like Receptor Agonism in Cancer Treatment and Progression. Cancers (Basel) 2022; 14:cancers14122923. [PMID: 35740589 PMCID: PMC9221178 DOI: 10.3390/cancers14122923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/02/2022] [Accepted: 06/13/2022] [Indexed: 01/05/2023] Open
Abstract
Simple Summary Toll like receptors (TLRs) are a group of transmembrane receptors belonging to the class of pattern recognition receptors (PRR), which are involved in recognition of pathogen associated molecular patterns (PAMPs), inducing immune response. During the past decade, a number of preclinical and clinical breakthroughs in the field of TLR agonists has immerged in cancer research and some of these agents have performed exceptionally well in clinical trials. Based on evidence from scientific studies, we draw attention to several microbial based TLR agonists and discuss their relevance in various cancer and explore various microbial based TLR agonists for developing effective immunotherapeutic strategies against cancer. Abstract Toll-like receptors (TLRs) are typical transmembrane proteins, which are essential pattern recognition receptors in mediating the effects of innate immunity. TLRs recognize structurally conserved molecules derived from microbes and damage-associated molecular pattern molecules that play an important role in inflammation. Since the first discovery of the Toll receptor by the team of J. Hoffmann in 1996, in Drosophila melanogaster, numerous TLRs have been identified across a wide range of invertebrate and vertebrate species. TLR stimulation leads to NF-κB activation and the subsequent production of pro-inflammatory cytokines and chemokines, growth factors and anti-apoptotic proteins. The expression of TLRs has also been observed in many tumors, and their stimulation results in tumor progression or regression, depending on the TLR and tumor type. The anti-tumoral effects can result from the activation of anti-tumoral immune responses and/or the direct induction of tumor cell death. The pro-tumoral effects may be due to inducing tumor cell survival and proliferation or by acting on suppressive or inflammatory immune cells in the tumor microenvironment. The aim of this review is to draw attention to the effects of TLR stimulation in cancer, the activation of various TLRs by microbes in different types of tumors, and, finally, the role of TLRs in anti-cancer immunity and tumor rejection.
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3
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Rostamizadeh L, Molavi O, Rashid M, Ramazani F, Baradaran B, Lavasanaifar A, Lai R. Recent advances in cancer immunotherapy: Modulation of tumor microenvironment by Toll-like receptor ligands. BIOIMPACTS : BI 2022; 12:261-290. [PMID: 35677663 PMCID: PMC9124882 DOI: 10.34172/bi.2022.23896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 11/29/2021] [Accepted: 12/04/2021] [Indexed: 12/18/2022]
Abstract
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Immunotherapy is considered a promising approach for cancer treatment. An important strategy for cancer immunotherapy is the use of cancer vaccines, which have been widely used for cancer treatment. Despite the great potential of cancer vaccines for cancer treatment, their therapeutic effects in clinical settings have been limited. The main reason behind the lack of significant therapeutic outcomes for cancer vaccines is believed to be the immunosuppressive tumor microenvironment (TME). The TME counteracts the therapeutic effects of immunotherapy and provides a favorable environment for tumor growth and progression. Therefore, overcoming the immunosuppressive TME can potentially augment the therapeutic effects of cancer immunotherapy in general and therapeutic cancer vaccines in particular. Among the strategies developed for overcoming immunosuppression in TME, the use of toll-like receptor (TLR) agonists has been suggested as a promising approach to reverse immunosuppression. In this paper, we will review the application of the four most widely studied TLR agonists including agonists of TLR3, 4, 7, and 9 in cancer immunotherapy.
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Affiliation(s)
- Leila Rostamizadeh
- Department of Molecular Medicine, Faculty of Advanced Medical Science, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ommoleila Molavi
- Biotechnology Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohsen Rashid
- Department of Molecular Medicine, Faculty of Advanced Medical Science, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Fatemeh Ramazani
- Department of Molecular Medicine, Faculty of Advanced Medical Science, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Behzad Baradaran
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Afsaneh Lavasanaifar
- Faculty of Pharmacy and Pharmaceutical Science, University of Alberta, Edmonton, Canada
| | - Raymond Lai
- Department of Laboratory Medicine & Pathology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Canada
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4
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Chung SW, Xie Y, Suk JS. Overcoming physical stromal barriers to cancer immunotherapy. Drug Deliv Transl Res 2021; 11:2430-2447. [PMID: 34351575 PMCID: PMC8571040 DOI: 10.1007/s13346-021-01036-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2021] [Indexed: 12/17/2022]
Abstract
Immunotherapy has emerged as an unprecedented hope for the treatment of notoriously refractory cancers. Numerous investigational drugs and immunotherapy-including combination regimens are under preclinical and clinical investigation. However, only a small patient subpopulation across different types of cancer responds to the therapy due to the presence of several mechanisms of resistance. There have been extensive efforts to overcome this limitation and to expand the patient population that could be benefited by this state-of-the-art therapeutic modality. Among various causes of the resistance, we here focus on physical stromal barriers that impede the access of immunotherapeutic drug molecules and/or native and engineered immune cells to cancer tissues and cells. Two primary stromal barriers that contribute to the resistance include aberrant tumor vasculatures and excessive extracellular matrix build-ups that restrict extravasation and infiltration, respectively, of molecular and cellular immunotherapeutic agents into tumor tissues. Here, we review the features of these barriers that limit the efficacy of immunotherapy and discuss recent advances that could potentially help immunotherapy overcome the barriers and improve therapeutic outcomes.
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Affiliation(s)
- Seung Woo Chung
- Center for Nanomedicine, The Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, MD, 602921231, USA
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA
| | - Yunxuan Xie
- Center for Nanomedicine, The Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, MD, 602921231, USA
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, 21218, USA
| | - Jung Soo Suk
- Center for Nanomedicine, The Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, MD, 602921231, USA.
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, 21218, USA.
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5
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Zhong G, Jin G, Zeng W, Yu C, Li Y, Zhou J, Zhang L, Yu L. Conjugation of TLR7 Agonist Combined with Demethylation Treatment Improves Whole-Cell Tumor Vaccine Potency in Acute Myeloid Leukemia. Int J Med Sci 2020; 17:2346-2356. [PMID: 32922200 PMCID: PMC7484644 DOI: 10.7150/ijms.49983] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/09/2020] [Indexed: 11/06/2022] Open
Abstract
Background: Acute myeloid leukemia (AML) is a malignant hematological disease with high refractory rate. Immune escape of AML cells is one of the underlying mechanisms mediating the relapse of the cancers. Various immunotherapies based on the 'patients' immune response to tumor cells have been developed to targeting the immune escape of AML cells, which lead to the minimal residual disease (MRD) after treatment. But the efficacy of those treatments or the combination of treatments remains unsatisfactory. Methods: A Toll-like receptor (TLR)-7 agonist SZU-106 was chemically synthesized. SZU-106 was conjugated to Decitabine (DAC), a demethylation agent, treated AML cells to construct tumor vaccine. The potency of the newly constructed AML cell vaccine, SZU-106-DAC-AML was tested in vitro and in vivo for the expression of tumor antigens and the activation level of immune responses. Results: Compared to the well characterized TLR7 agonist R848, SZU-106 has a comparable potency to activate TLR7 signaling pathway. SZU-106-DAC-AML, constructed by conjugating SZU-106 to DAC treated tumor cells, exhibited increased expression of tumor antigens, and enhanced the activation of DC cells and T cells in vitro and in vivo. The result of xenograft tumor model showed that SZU-106-DAC-AML tumor vaccine greatly inhibited tumor growth and prolonged animal survival. Conclusions: Conjugation of TLR7 agonist combined with up-regulation of tumor antigen expression improved the effectiveness of whole-cell tumor vaccine in AML.
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Affiliation(s)
- Guocheng Zhong
- Department of Hematology and BMT center, the first Medical Center, Chinese PLA General Hospital. Beijing 100853, China
- Department of Hematology and Oncology, Shenzhen University General Hospital, Shenzhen 518055, China
| | - Guangyi Jin
- Carson International Cancer Center, Department of Medicine, Shenzhen University, Shenzhen 518037, China
| | - Wei Zeng
- Department of Hematology and Oncology, Shenzhen University General Hospital, Shenzhen 518055, China
| | - Changhua Yu
- Department of Hematology and Oncology, Shenzhen University General Hospital, Shenzhen 518055, China
| | - Yan Li
- Department of Hematology and BMT center, the first Medical Center, Chinese PLA General Hospital. Beijing 100853, China
| | - Ji Zhou
- Carson International Cancer Center, Department of Medicine, Shenzhen University, Shenzhen 518037, China
| | - Li Zhang
- Carson International Cancer Center, Department of Medicine, Shenzhen University, Shenzhen 518037, China
| | - Li Yu
- Department of Hematology and BMT center, the first Medical Center, Chinese PLA General Hospital. Beijing 100853, China
- Department of Hematology and Oncology, Shenzhen University General Hospital, Shenzhen 518055, China
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6
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Patinote C, Karroum NB, Moarbess G, Cirnat N, Kassab I, Bonnet PA, Deleuze-Masquéfa C. Agonist and antagonist ligands of toll-like receptors 7 and 8: Ingenious tools for therapeutic purposes. Eur J Med Chem 2020; 193:112238. [PMID: 32203790 PMCID: PMC7173040 DOI: 10.1016/j.ejmech.2020.112238] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 12/17/2022]
Abstract
The discovery of the TLRs family and more precisely its functions opened a variety of gates to modulate immunological host responses. TLRs 7/8 are located in the endosomal compartment and activate a specific signaling pathway in a MyD88-dependant manner. According to their involvement into various autoimmune, inflammatory and malignant diseases, researchers have designed diverse TLRs 7/8 ligands able to boost or block the inherent signal transduction. These modulators are often small synthetic compounds and most act as agonists and to a much lesser extent as antagonists. Some of them have reached preclinical and clinical trials, and only one has been approved by the FDA and EMA, imiquimod. The key to the success of these modulators probably lies in their combination with other therapies as recently demonstrated. We gather in this review more than 360 scientific publications, reviews and patents, relating the extensive work carried out by researchers on the design of TLRs 7/8 modulators, which are classified firstly by their biological activities (agonist or antagonist) and then by their chemical structures, which total syntheses are not discussed here. This review also reports about 90 clinical cases, thereby showing the biological interest of these modulators in multiple pathologies.
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Affiliation(s)
- Cindy Patinote
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France.
| | - Nour Bou Karroum
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France; Tumorigenèse et Pharmacologie Antitumorale, Lebanese University, EDST, BP 90656, Fanar Jdeideh, Lebanon
| | - Georges Moarbess
- Tumorigenèse et Pharmacologie Antitumorale, Lebanese University, EDST, BP 90656, Fanar Jdeideh, Lebanon
| | - Natalina Cirnat
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France
| | - Issam Kassab
- Tumorigenèse et Pharmacologie Antitumorale, Lebanese University, EDST, BP 90656, Fanar Jdeideh, Lebanon
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7
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Chi H, Li C, Zhao FS, Zhang L, Ng TB, Jin G, Sha O. Anti-tumor Activity of Toll-Like Receptor 7 Agonists. Front Pharmacol 2017; 8:304. [PMID: 28620298 PMCID: PMC5450331 DOI: 10.3389/fphar.2017.00304] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/10/2017] [Indexed: 01/04/2023] Open
Abstract
Toll-like receptors (TLRs) are a class of pattern recognition receptors that play a bridging role in innate immunity and adaptive immunity. The activated TLRs not only induce inflammatory responses, but also elicit the development of antigen specific immunity. TLR7, a member of TLR family, is an intracellular receptor expressed on the membrane of endosomes. TLR7 can be triggered not only by ssRNA during viral infections, but also by immune modifiers that share a similar structure to nucleosides. Its powerful immune stimulatory action can be potentially used in the anti-tumor therapy. This article reviewed the anti-tumor activity and mechanism of TLR7 agonists that are frequently applied in preclinical and clinical investigations, and mainly focused on small synthetic molecules, including imiquimod, resiquimod, gardiquimod, and 852A, etc.
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Affiliation(s)
- Huju Chi
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science CentreShenzhen, China
| | - Chunman Li
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science CentreShenzhen, China
| | - Flora Sha Zhao
- School of Life Sciences, Faculty of Science, The Chinese University of Hong KongHong Kong, Hong Kong
| | - Li Zhang
- Department of Physiology and Neurology, University of ConnecticutStorrs, CT, United States
| | - Tzi Bun Ng
- Departmet of Biochemistry, Faculty of Science, The Chinese University of Hong KongHong Kong, Hong Kong
| | - Guangyi Jin
- Department of Pharmacy, Shenzhen University Health Science CentreShenzhen, China
| | - Ou Sha
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science CentreShenzhen, China
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8
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Gao N, Zhong J, Wang X, Jin Z, Li W, Liu Y, Diao Y, Wang Z, Jiang W, Jin G. Immunomodulatory and Antitumor Effects of a Novel TLR7 Agonist Combined with Lapatinib. Sci Rep 2016; 6:39598. [PMID: 28000738 PMCID: PMC5175151 DOI: 10.1038/srep39598] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 11/25/2016] [Indexed: 02/06/2023] Open
Abstract
As new treatment approaches, both immunotherapy and targeted treatments have been used in the clinical treatment of cancers. These therapies are different from traditional surgery, chemotherapy and radiotherapy. Use of a combination of immunotherapy and targeted treatments may improve tumor clearance. We investigated the feasibility of combining tyrosine kinase inhibitors (TKIs, targeted drugs) and SZU-101 (a novel TLR7 agonist synthesized by our laboratory). Thirteen different TKIs were combined with or without SZU-101 and studied to determine their effects on immunocytes. On the basis of the distinctive results, lapatinib and sunitinib were selected for further tumor-inhibition investigation and determination of the underlying mechanism. Interestingly, we found lapatinib to work better with SZU-101, enhancing tumor clearance in vivo, without affecting the TLR7-NF-κB pathway activated by the TLR7 agonist in mouse spleen lymphocytes and bone marrow dendritic cells (BMDCs).
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Affiliation(s)
- Ningning Gao
- National-Regional Key Technology Engineering Laboratory for Synthetic Biology of Medicine, Shenzhen University, Shenzhen 518060, People's Republic of China.,Cancer Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Department of Pharmacy, School of Medicine, Health Science Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Sun Yat-sen University Cancer Center, Guangzhou 510060, People's Republic of China
| | - Jingjing Zhong
- National-Regional Key Technology Engineering Laboratory for Synthetic Biology of Medicine, Shenzhen University, Shenzhen 518060, People's Republic of China.,Cancer Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Department of Pharmacy, School of Medicine, Health Science Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Xiaodong Wang
- National-Regional Key Technology Engineering Laboratory for Synthetic Biology of Medicine, Shenzhen University, Shenzhen 518060, People's Republic of China.,Cancer Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Department of Pharmacy, School of Medicine, Health Science Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Zhenchao Jin
- National-Regional Key Technology Engineering Laboratory for Synthetic Biology of Medicine, Shenzhen University, Shenzhen 518060, People's Republic of China.,Cancer Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Department of Pharmacy, School of Medicine, Health Science Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Wang Li
- National-Regional Key Technology Engineering Laboratory for Synthetic Biology of Medicine, Shenzhen University, Shenzhen 518060, People's Republic of China.,Cancer Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Department of Pharmacy, School of Medicine, Health Science Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Yu Liu
- National-Regional Key Technology Engineering Laboratory for Synthetic Biology of Medicine, Shenzhen University, Shenzhen 518060, People's Republic of China.,Cancer Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Department of Pharmacy, School of Medicine, Health Science Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Yuwen Diao
- National-Regional Key Technology Engineering Laboratory for Synthetic Biology of Medicine, Shenzhen University, Shenzhen 518060, People's Republic of China.,Cancer Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Department of Pharmacy, School of Medicine, Health Science Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Zhulin Wang
- Conjugenix company of Shenzhen, Shenzhen 518063, People's Republic of China
| | - Wenqi Jiang
- Cancer Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Sun Yat-sen University Cancer Center, Guangzhou 510060, People's Republic of China
| | - Guangyi Jin
- National-Regional Key Technology Engineering Laboratory for Synthetic Biology of Medicine, Shenzhen University, Shenzhen 518060, People's Republic of China.,Cancer Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China.,Department of Pharmacy, School of Medicine, Health Science Center, Shenzhen University, Shenzhen 518060, People's Republic of China
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9
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Du Y, Du T, Shi Y, Zhang A, Zhang C, Diao Y, Jin G, Zhou EM. Synthetic Toll-like receptor 7 ligand inhibits porcine reproductive and respiratory syndrome virus infection in primary porcine alveolar macrophages. Antiviral Res 2016; 131:9-18. [PMID: 27079946 DOI: 10.1016/j.antiviral.2016.04.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 03/31/2016] [Accepted: 04/06/2016] [Indexed: 01/07/2023]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV), a common viral pathogen, causes huge annual economic losses to the swine industry worldwide. After triggering by specific ligands, the Toll-like receptor 7 (TLR7), a type of pattern-recognition receptor (PRR), induces antiviral cytokines production. Previously, we synthesized an adenine analog, designated SZU101, a TLR7-specific ligand. In this study, we assessed the inhibitory effect of SZU101 on PRRSV infection in vitro. SZU101 significantly suppressed PRRSV infection in primary porcine alveolar macrophages (PAMs) in a dose-dependent manner. Moreover, SZU101-induced inhibition involved NF-κB pathway activation in PAMs to initiate expression of TLR7-mediated cytokines and induce expression of downstream signaling IFN-stimulated genes (ISGs). Chloroquine, a TLR7 inhibitor, and BAY 11-7082, an NF-κB inhibitor, reversed both the SZU101-induced antiviral effect and induction of cytokine genes and ISGs expression. Therefore, SZU101 antiviral effects depend at least in part on TLR7-NF-κB signaling pathway. Additionally, administration of SZU101 enhanced the humoral and cell-mediated immune responses against PRRSV antigens in mice. Given these results, SZU101 holds promise as an antiviral agent and a vaccine adjuvant to prevent PRRSV infection in pigs.
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Affiliation(s)
- Yongkun Du
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi 712100, China.
| | - Taofeng Du
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi 712100, China.
| | - Yunpeng Shi
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi 712100, China.
| | - Angke Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi 712100, China.
| | - Chong Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi 712100, China.
| | - Yuwen Diao
- Cancer Research Center, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, School of Medicine, Shenzhen University, Shenzhen, Guangdong 518060, China; Shenzhen Engineering Laboratory of Synthetic Biology, Shenzhen, Guangdong 518060, China.
| | - Guangyi Jin
- Cancer Research Center, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, School of Medicine, Shenzhen University, Shenzhen, Guangdong 518060, China; Shenzhen Engineering Laboratory of Synthetic Biology, Shenzhen, Guangdong 518060, China.
| | - En-Min Zhou
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi 712100, China.
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