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Au SKW, Portelli IV, DeWitte-Orr SJ. Using long, sequence-specific dsRNA to knockdown inducible protein expression and virus production via an RNAi-like mechanism. FISH & SHELLFISH IMMUNOLOGY 2022; 131:945-957. [PMID: 36351544 DOI: 10.1016/j.fsi.2022.10.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
RNA interference (RNAi) is a powerful innate immune mechanism to knock down translation of specific proteins whose machinery is conserved from plants to mammals. The template used to determine which mRNA's translation is inhibited is dsRNA, whose origin can range from viruses (long dsRNA, ∼100-1000s bp) to host (micro(mi)RNA, ∼20mers). While miRNA-mediated RNAi is well described in vertebrates, the ability of long dsRNA to guide RNAi-mediated translation inhibition in vertebrates is controversial. Indeed, as long dsRNA is so effective at inducing type I interferons (IFNs), and IFNs down-regulate RNAi machinery, it is believed that IFN-competent cells are not capable of using long dsRNA for RNAi. In the present study the ability of long, sequence specific dsRNA to knock down both host protein expression and viral replication is investigated in IFN-competent rainbow trout cells. Before exploring RNAi effects, the optimal dsRNA concentration that would funnel into RNAi without triggering the IFN response was determined. After which, the ability of sequence specific long dsRNA to target knockdown via RNAi was evaluated in: (1) uninfected host cells using inducible luciferase gene expression and (2) host cells infected with chum salmon reovirus (CSV), frog virus 3 (FV3) or viral hemorrhagic septicemia virus genotype IVa (VHSV-IVa). Induced expression studies utilized RTG-P1, a luciferase reporter cell line, and dsRNA containing luciferase sequence (dsRNA-Luc) or a mis-matched sequence (dsRNA-GFP), and subsequent luminescence intensity was measured. Anti-CSV studies used dsRNA-CSVseg7 and dsRNA-CSVseg10 to target CSV segment 7 and CSV segment 10 respectively. Inhibition of virus replication was measured by viral titration and RT-qPCR. Taking advantage of the fact that long dsRNA can accommodate more sequences than miRNAs, the antiviral capability of dsRNA molecules containing both CSV segment 7 and segment 10 simultaneously was also measured. Target sequence appears important, as dsRNA-FV3MCP did not knock down FV3 titres, and while dsRNA-VHSV-N knocked down VHSV-IVa, dsRNA-VHSV-G and dsRNA-VHSV-M did not. This is the first study in fish to provide evidence that sequence specific long dsRNA induces potent gene expression silencing and antiviral responses in vitro via an RNAi-like mechanism instead of an IFN-dependent response.
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Affiliation(s)
- Sarah K W Au
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada; Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Iliana V Portelli
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Stephanie J DeWitte-Orr
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada; Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada.
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2
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Kurisu N, Kaminade T, Eguchi M, Ishigami I, Mizuguchi H, Sakurai F. Oncolytic reovirus-mediated killing of mouse cancer-associated fibroblasts. Int J Pharm 2021; 610:121269. [PMID: 34748806 DOI: 10.1016/j.ijpharm.2021.121269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 10/25/2021] [Accepted: 11/01/2021] [Indexed: 12/28/2022]
Abstract
Oncolytic viruses, which mediate tumor cell-specific infection, resulting in efficient tumor cell killing, have attracted much attention as a novel class of anti-cancer biopharmaceutical agents. Cancer-associated fibroblasts (CAFs) are an important component of the tumor microenvironment that strongly supports the growth, survival, and metastasis of tumor cells, suggesting that CAFs would have influence to the antitumor effects of oncolytic viruses; however, it remains to be fully evaluated whether oncolytic viruses affect the viabilities and properties of CAFs following treatment. Oncolytic reovirus, which is a non-enveloped virus that contains 10-segmented double-stranded RNA genome, shows efficient tumor cell lysis without apparent cytotoxicity to normal cells and has been tested worldwide in clinical trials against various types of tumors. In this study, we demonstrated that reovirus exhibited cytotoxicity against mouse primary CAFs isolated from subcutaneous tumors, but not against tail-tip fibroblasts. Infection with reovirus resulted in activation of caspase 3 and up-regulation of apoptosis-related gene expression, indicating that reovirus induced apoptosis of mouse primary CAFs. Intratumoral administration of reovirus induced apoptosis of mouse CAFs in the tumor. Taken together, these results indicate that reovirus has the potential to mediate antitumor effects by killing not only cancer cells but also CAFs.
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Affiliation(s)
- Nozomi Kurisu
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Tadataka Kaminade
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Maho Eguchi
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Ikuho Ishigami
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Hiroyuki Mizuguchi
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan; Laboratory of Hepatocyte Regulation, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan; The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Osaka, Japan
| | - Fuminori Sakurai
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan.
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3
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Inoue C, Negoro R, Takayama K, Mizuguchi H, Sakurai F. Asymmetric profiles of infection and innate immunological responses in human iPS cell-derived small intestinal epithelial-like cell monolayers following infection with mammalian reovirus. Virus Res 2021; 296:198334. [PMID: 33581186 DOI: 10.1016/j.virusres.2021.198334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 11/20/2022]
Abstract
The intestinal mucosa plays an important role as an immune barrier due to its continual exposure to invading pathogens, including viruses. It is thus highly important to evaluate virus infection profiles in the intestinal mucosa for prevention of virus infection and development of antivirus medicines; however, only a few enterocyte lines are available as in vitro intestinal models for the evaluation of virus infection. In this study, we evaluated profiles of infection and innate immune responses following infection with a mammalian orthoreovirus (hereafter reovirus), which has often been used as a tractable model for studies of viral pathogenesis, in human iPS cell-derived small intestinal epithelial-like cell (hiPS-SIEC) monolayers and cells of a human colon adenocarcinoma cell line, Caco-2. The levels of reovirus infection were similar between hiPS-SIEC and Caco-2 cell monolayers, which are often used as an intestinal model, after apical and basolateral infection. In hiPS-SIEC monolayers, more efficient replication of the virus genome was observed following basolateral infection than apical infection, while apical infection resulted in higher levels of virus protein expression and progeny virus production than basolateral infection. Reovirus significantly induced innate immune responses, including expression of type I and III interferons (IFNs), in hiPS-SIEC monolayers more efficiently than Caco-2 cells. Higher levels of type I and III interferon (IFN) expression were found in hiPS-SIEC monolayers following apical infection than basolateral infection. These results suggested that hiPS-SIECs are a promising in vitro model for the evaluation of virus infection.
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Affiliation(s)
- Chieko Inoue
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Ryosuke Negoro
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Kazuo Takayama
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan; PRESTO, Japan Science and Technology Agency, Saitama, Japan; Laboratory of Hepatocyte Regulation, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - Hiroyuki Mizuguchi
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan; PRESTO, Japan Science and Technology Agency, Saitama, Japan; The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Osaka, Japan.
| | - Fuminori Sakurai
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan.
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Katayama Y, Tachibana M, Kurisu N, Oya Y, Terasawa Y, Goda H, Kobiyama K, Ishii KJ, Akira S, Mizuguchi H, Sakurai F. Oncolytic Reovirus Inhibits Immunosuppressive Activity of Myeloid-Derived Suppressor Cells in a TLR3-Dependent Manner. THE JOURNAL OF IMMUNOLOGY 2018; 200:2987-2999. [PMID: 29555782 DOI: 10.4049/jimmunol.1700435] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 02/21/2018] [Indexed: 12/24/2022]
Abstract
Oncolytic reovirus, which possesses 10 segments of dsRNA genome, mediates antitumor effects via not only virus replication in a tumor cell-specific manner, but also activation of antitumor immunity; however, the mechanism(s) of reovirus-induced activation of antitumor immunity have not been fully elucidated. Recent studies have demonstrated that overcoming an immunosuppressive environment in tumor-bearing hosts is important to achieve efficient activation of antitumor immunity. Among the various types of cells involved in immunosuppression, it has been revealed that myeloid-derived suppressor cells (MDSCs) are significantly increased in tumor-bearing hosts and play crucial roles in the immunosuppression in tumor-bearing hosts. In this study, we examined whether reovirus inhibits the immunosuppressive activity of MDSCs, resulting in efficient activation of immune cells after in vivo administration. The results showed that splenic MDSCs recovered from PBS-treated tumor-bearing mice significantly suppressed the Ag-specific proliferation of CD8+ T cells. In contrast, the suppressive activity of MDSCs on T cell proliferation was significantly reduced after reovirus administration. Reovirus also inhibited the immunosuppressive activity of MDSCs in IFN-β promoter stimulator-1 knockout (KO) mice and in wild-type mice. In contrast, the immunosuppressive activity of MDSCs in TLR-3 KO mice was not significantly altered by reovirus treatment. The activation levels of CD4+ and CD8+ T cells were significantly lower in TLR3 KO mice than in wild-type mice after reovirus administration. These results indicate that reovirus inhibits the immunosuppressive activity of MDSCs in a TLR3, but not IFN-β promoter stimulator-1, signaling-dependent manner.
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Affiliation(s)
- Yuki Katayama
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masashi Tachibana
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Nozomi Kurisu
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yukako Oya
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yuichi Terasawa
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hiroshi Goda
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kouji Kobiyama
- Laboratory of Adjuvant Innovation, Center for Vaccine and Adjuvant Research, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka 567-0085, Japan.,Laboratory of Vaccine Science, World Premier International Research Center Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Ken J Ishii
- Laboratory of Adjuvant Innovation, Center for Vaccine and Adjuvant Research, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka 567-0085, Japan.,Laboratory of Vaccine Science, World Premier International Research Center Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Shizuo Akira
- Laboratory of Host Defense, World Premier International Research Center Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan.,Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hiroyuki Mizuguchi
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan.,Laboratory of Hepatocyte Differentiation, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka 567-0085, Japan.,Global Center for Medical Engineering and Informatics, Osaka University, Osaka 565-0871, Japan; and
| | - Fuminori Sakurai
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan; .,Laboratory of Regulatory Sciences for Oligonucleotide Therapeutics, Clinical Drug Development Unit, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
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Oncolytic virotherapy as an immunotherapeutic strategy for multiple myeloma. Blood Cancer J 2017; 7:640. [PMID: 29208938 PMCID: PMC5802552 DOI: 10.1038/s41408-017-0020-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/03/2017] [Accepted: 10/12/2017] [Indexed: 12/22/2022] Open
Abstract
Multiple Myeloma (MM), a clonal malignancy of antibody-producing plasma cells, is the second most common hematologic malignancy and results in significant patient morbidity and mortality. The high degree of immune dysregulation in MM, including T cell imbalances and up-regulation of immunosuppressive checkpoint proteins and myeloid derived suppressor cells, allows this malignancy to escape from host immune control. Despite advances in the therapeutic landscape of MM over the last decade, including the introduction of immunomodulatory drugs, the prognosis for this disease is poor, with less than 50% of patients surviving 5 years. Thus, novel treatment strategies are required. Oncolytic viruses (OV) are a promising new class of therapeutics that rely on tumour specific oncolysis and the generation of a potent adaptive anti-tumour immune response for efficacy. To date, a number of OV have shown efficacy in pre-clinical studies of MM with three reaching early phase clinical trials. OVs represent a rational therapeutic strategy for MM based on (1) their tumour tropism, (2) their ability to potentiate anti-tumour immunity and (3) their ability to be rationally combined with other immunotherapeutic agents to achieve a more robust clinical response.
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PUMA and NF-kB Are Cell Signaling Predictors of Reovirus Oncolysis of Breast Cancer. PLoS One 2017; 12:e0168233. [PMID: 28099441 PMCID: PMC5243128 DOI: 10.1371/journal.pone.0168233] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/28/2016] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND AND PURPOSE Reovirus is a ubiquitous RNA virus that exploits aberrant signaling pathways for its replication. The oncolytic potential of reovirus against numerous cancers under pre-clinical/clinical conditions has been documented by us and others. Despite its proven clinical activity, the underlying mechanisms of reovirus oncolysis is still not well elucidated. If reovirus therapy is to be optimized for cancer, including breast cancer patients, it is imperative to understand the mechanisms of reovirus oncolysis, especially in treatment of resistant tumour. EXPERIMENTAL APPROACH AND RESULTS In the present study global gene expression profiling was utilized as a preliminary roadmap to tease-out pivotal molecules involved in reovirus induced apoptosis in breast cancer. Reovirus treated HTB133 and MCF7 breast cancer cells revealed transcriptional alteration of a defined subset of apoptotic genes and members of the nuclear factor-kappa B (NF-kB) family and p53 upregulated modulator of apoptosis (PUMA) were prominent. Since NF-kB can paradoxically suppress or promote apoptosis in cancer, the significance of NF-kB in reovirus oncolysis of breast cancer was investigated. Real time PCR analysis indicated a 2.9-4.3 fold increase in NF-kB p65 message levels following reovirus infection of MCF7 and HTB133, respectively. Nuclear translocation of NF-kB p65 protein was also dramatically augmented post reovirus treatment and correlated with enhanced DNA binding. Pharmacologic inhibition of NF-kB lead to oncolytic protection and significant down regulation of PUMA message levels. PUMA down regulation using siRNA suppressed reovirus oncolysis via significantly repressed apoptosis in p53 mutant HTB133 cells. CONCLUSIONS This study demonstrates for the first time that a prominent pathway of reovirus oncolysis of breast cancer is mediated through NF-kB and that PUMA upregulation is dependent on NF-kB activation. These findings represent potential therapeutic indicators of reovirus treatment in future clinical trials.
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7
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Stiff A, Caserta E, Sborov DW, Nuovo GJ, Mo X, Schlotter SY, Canella A, Smith E, Badway J, Old M, Jaime-Ramirez AC, Yan P, Benson DM, Byrd JC, Baiocchi R, Kaur B, Hofmeister CC, Pichiorri F. Histone Deacetylase Inhibitors Enhance the Therapeutic Potential of Reovirus in Multiple Myeloma. Mol Cancer Ther 2016; 15:830-41. [PMID: 26809490 DOI: 10.1158/1535-7163.mct-15-0240-t] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 11/23/2015] [Indexed: 11/16/2022]
Abstract
Multiple myeloma remains incurable and the majority of patients die within 5 years of diagnosis. Reolysin, the infusible form of human reovirus (RV), is a novel viral oncolytic therapy associated with antitumor activity likely resulting from direct oncolysis and a virus-mediated antitumor immune response. Results from our phase I clinical trial investigating single agent Reolysin in patients with relapsed multiple myeloma confirmed tolerability, but no objective responses were evident, likely because the virus selectively entered the multiple myeloma cells but did not actively replicate. To date, the precise mechanisms underlying the RV infectious life cycle and its ability to induce oncolysis in patients with multiple myeloma remain unknown. Here, we report that junctional adhesion molecule 1 (JAM-1), the cellular receptor for RV, is epigenetically regulated in multiple myeloma cells. Treatment of multiple myeloma cells with clinically relevant histone deacetylase inhibitors (HDACi) results in increased JAM-1 expression as well as increased histone acetylation and RNA polymerase II recruitment to its promoter. Furthermore, our data indicate that the combination of Reolysin with HDACi, potentiates RV killing activity of multiple myeloma cells in vitro and in vivo This study provides the molecular basis to use these agents as therapeutic tools to increase the efficacy of RV therapy in multiple myeloma. Mol Cancer Ther; 15(5); 830-41. ©2016 AACR.
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Affiliation(s)
- Andrew Stiff
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Enrico Caserta
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Douglas W Sborov
- Department of Internal Medicine, Oncology/Hematology Fellowship, The Ohio State University, Columbus, Ohio
| | - Gerard J Nuovo
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Xiaokui Mo
- Center for Biostatistics, Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio
| | - Sarah Y Schlotter
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | | | - Emily Smith
- Biomedical Sciences Graduate Program, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Joseph Badway
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Matthew Old
- Division of Medical Oncology, Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Alena Cristina Jaime-Ramirez
- Department of Neurological Surgery, Dardinger Laboratory for Neuro-oncology and Neurosciences, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Pearlly Yan
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Don M Benson
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - John C Byrd
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Robert Baiocchi
- Department of Neurological Surgery, Dardinger Laboratory for Neuro-oncology and Neurosciences, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Balveen Kaur
- Department of Neurological Surgery, Dardinger Laboratory for Neuro-oncology and Neurosciences, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Craig C Hofmeister
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Flavia Pichiorri
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.
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Hotani T, Tachibana M, Mizuguchi H, Sakurai F. Reovirus double-stranded RNA genomes and polyI:C induce down-regulation of hypoxia-inducible factor 1α. Biochem Biophys Res Commun 2015; 460:1041-6. [PMID: 25843794 DOI: 10.1016/j.bbrc.2015.03.147] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 03/25/2015] [Indexed: 10/23/2022]
Abstract
Reovirus has genomes consisting of 10-segmented double-stranded RNAs, and have received much attention as an oncolytic virus. A previous study reported that reovirus down-regulates hypoxia-inducible factor 1α (HIF-1α) protein levels following infection in tumor cells, which contributes to the antitumor effects of reovirus; however, the mechanism remains to be elucidated. In this study, we examined which virus component was involved in reovirus-mediated down-regulation of HIF-1α. Reovirus induced significant down-regulation of HIF-1α protein levels in not only reovirus-permissive tumor cells but also reovirus-resistant tumor cells. UV-inactivated reovirus also induced a reduction in HIF-1α protein levels. These data indicate that reovirus induces HIF-1α down-regulation independently of virus replication. Furthermore, transfection with not only reovirus genomes but also polyI:C efficiently induced HIF-1α down-regulation in a manner similar to reovirus, indicating that double-stranded reovirus RNA genomes are a key component for HIF-1α down-regulation. Reovirus-mediated HIF-1α down-regulation was inhibited when tumor cells were pretreated with inhibitors of cathepsins B and L, which play a crucial role in endo-lysosomal escape of virions to the cytoplasm. These data suggest that endo-lysosomal escape of reovirus genome into the cytoplasm is crucial for HIF-1α down-regulation; however, the retinoic acid-inducible gene-I (RIG-I) or interferon-β promoter stimulator-1 (IPS-1), which are involved in reovirus genome-induced innate immunity in the cytoplasm, did not play a crucial role in reovirus-mediated HIF-1α reduction.
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Affiliation(s)
- Takuma Hotani
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Masashi Tachibana
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Hiroyuki Mizuguchi
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan; Laboratory of Hepatic Differentiation Research, National Institute of Biomedical Innovation, Osaka, Japan; Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan; Laboratory of iPS Research, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Fuminori Sakurai
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan; Laboratory of Regulatory Sciences for Oligonucleotide Therapeutics, Clinical Drug Development Unit, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan.
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