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Lee KH, Kim S, Song J, Han SR, Kim JH, Lee SW. Efficient circular RNA engineering by end-to-end self-targeting and splicing reaction using Tetrahymena group I intron ribozyme. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 33:587-598. [PMID: 37637208 PMCID: PMC10457212 DOI: 10.1016/j.omtn.2023.07.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 07/28/2023] [Indexed: 08/29/2023]
Abstract
Circular RNA (circRNA) has various advantages over linear mRNA that is gaining success as a new vaccine and therapeutic agent. Thus, circRNA and its engineering methods have attracted attention recently. In this study, we developed a new in vitro circRNA engineering method by end-to-end self-targeting and splicing (STS) reaction using Tetrahymena group I intron ribozyme. We found that only the P1 helix structure of the group I intron was enough to generate circRNA by STS reaction. The efficacy of circRNA generation by STS reaction was comparable to the method using a permuted intron-exon (PIE) reaction. However, an end-to-end STS reaction does not introduce any extraneous fragments, such as an intronic scar that can be generated by PIE reaction and might trigger unwanted innate immune responses in cells, into circRNA sequences. Moreover, generated circRNA was efficiently purified by ion pair-reversed phase high-pressure liquid chromatography and used for cell-based analysis. Of note, efficient protein expression and stability with least innate immune induction by the circRNA with coxsackievirus B3 IRES were observed in cells. In conclusion, our new in vitro circRNA strategy can effectively generate highly useful circRNAs in vitro as an alternative circRNA engineering method.
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Affiliation(s)
- Kyung Hyun Lee
- R&D Center, Rznomics Inc, Seongnam 13486, Republic of Korea
| | - Seongcheol Kim
- R&D Center, Rznomics Inc, Seongnam 13486, Republic of Korea
| | - Jaehwi Song
- R&D Center, Rznomics Inc, Seongnam 13486, Republic of Korea
| | - Seung Ryul Han
- R&D Center, Rznomics Inc, Seongnam 13486, Republic of Korea
| | - Ji Hyun Kim
- R&D Center, Rznomics Inc, Seongnam 13486, Republic of Korea
| | - Seong-Wook Lee
- R&D Center, Rznomics Inc, Seongnam 13486, Republic of Korea
- Department of Bioconvergence Engineering, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea
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2
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Shi X, Won M, Tang C, Ding Q, Sharma A, Wang F, Kim JS. RNA splicing based on reporter genes system: Detection, imaging and applications. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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3
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Tickner ZJ, Farzan M. Riboswitches for Controlled Expression of Therapeutic Transgenes Delivered by Adeno-Associated Viral Vectors. Pharmaceuticals (Basel) 2021; 14:ph14060554. [PMID: 34200913 PMCID: PMC8230432 DOI: 10.3390/ph14060554] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/28/2021] [Accepted: 06/04/2021] [Indexed: 11/16/2022] Open
Abstract
Vectors developed from adeno-associated virus (AAV) are powerful tools for in vivo transgene delivery in both humans and animal models, and several AAV-delivered gene therapies are currently approved for clinical use. However, AAV-mediated gene therapy still faces several challenges, including limited vector packaging capacity and the need for a safe, effective method for controlling transgene expression during and after delivery. Riboswitches, RNA elements which control gene expression in response to ligand binding, are attractive candidates for regulating expression of AAV-delivered transgene therapeutics because of their small genomic footprints and non-immunogenicity compared to protein-based expression control systems. In addition, the ligand-sensing aptamer domains of many riboswitches can be exchanged in a modular fashion to allow regulation by a variety of small molecules, proteins, and oligonucleotides. Riboswitches have been used to regulate AAV-delivered transgene therapeutics in animal models, and recently developed screening and selection methods allow rapid isolation of riboswitches with novel ligands and improved performance in mammalian cells. This review discusses the advantages of riboswitches in the context of AAV-delivered gene therapy, the subsets of riboswitch mechanisms which have been shown to function in human cells and animal models, recent progress in riboswitch isolation and optimization, and several examples of AAV-delivered therapeutic systems which might be improved by riboswitch regulation.
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Affiliation(s)
- Zachary J. Tickner
- Department of Immunology and Microbiology, the Scripps Research Institute, Jupiter, FL 33458, USA;
- Correspondence:
| | - Michael Farzan
- Department of Immunology and Microbiology, the Scripps Research Institute, Jupiter, FL 33458, USA;
- Emmune, Inc., Jupiter, FL 33458, USA
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4
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Han SR, Lee CH, Im JY, Kim JH, Kim JH, Kim SJ, Cho YW, Kim E, Kim Y, Ryu JH, Ju MH, Jeong JS, Lee SW. Targeted suicide gene therapy for liver cancer based on ribozyme-mediated RNA replacement through post-transcriptional regulation. MOLECULAR THERAPY. NUCLEIC ACIDS 2020; 23:154-168. [PMID: 33335800 PMCID: PMC7732968 DOI: 10.1016/j.omtn.2020.10.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 10/24/2020] [Indexed: 12/16/2022]
Abstract
Hepatocellular carcinoma (HCC) has high fatality rate and limited therapeutic options. Here, we propose a new anti-HCC approach with high cancer-selectivity and efficient anticancer effects, based on adenovirus-mediated Tetrahymena group I trans-splicing ribozymes specifically inducing targeted suicide gene activity through HCC-specific replacement of telomerase reverse transcriptase (TERT) RNA. To confer potent anti-HCC effects and minimize hepatotoxicity, we constructed post-transcriptionally enhanced ribozyme constructs coupled with splicing donor and acceptor site and woodchuck hepatitis virus post-transcriptional regulatory element under the control of microRNA-122a (miR-122a). Adenovirus encoding post-transcriptionally enhanced ribozyme improved trans-splicing reaction and decreased human TERT (hTERT) RNA level, efficiently and selectively retarding hTERT-positive liver cancers. Adenovirus encoding miR-122a-regulated ribozyme caused selective liver cancer cytotoxicity, the efficiency of which depended on ribozyme expression level relative to miR-122a level. Systemic administration of adenovirus encoding the post-transcriptionally enhanced and miR-regulated ribozyme caused efficient anti-cancer effects at a single dose of low titers and least hepatotoxicity in intrahepatic multifocal HCC mouse xenografts. Minimal liver toxicity, tissue distribution, and clearance pattern of the recombinant adenovirus were observed in normal animals administered either systemically or via the hepatic artery. Post-transcriptionally regulated RNA replacement strategy mediated by a cancer-specific ribozyme provides a clinically relevant, safe, and efficient strategy for HCC treatment.
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Affiliation(s)
- Seung Ryul Han
- R&D Center, Rznomics, Inc., Seongnam 13486, Republic of Korea
| | - Chang Ho Lee
- Department of Life Convergence, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea
| | - Ji Young Im
- Department of Life Convergence, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea
| | - Ju Hyun Kim
- Department of Life Convergence, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea
| | - Ji Hyun Kim
- R&D Center, Rznomics, Inc., Seongnam 13486, Republic of Korea
| | - Sung Jin Kim
- Department of Life Convergence, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea
| | - Young Woo Cho
- New Drug Development Center, Osong Medical Innovation Foundation, Cheongju 28160, Republic of Korea.,College of Pharmacy, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Eunkyung Kim
- New Drug Development Center, Osong Medical Innovation Foundation, Cheongju 28160, Republic of Korea.,College of Pharmacy, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Youngah Kim
- New Drug Development Center, Osong Medical Innovation Foundation, Cheongju 28160, Republic of Korea
| | - Ji-Ho Ryu
- New Drug Development Center, Osong Medical Innovation Foundation, Cheongju 28160, Republic of Korea.,College of Pharmacy, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Mi Ha Ju
- Department of Pathology and Immune-network Pioneer Research Center, Dong-A University College of Medicine, Busan 602-714, Republic of Korea
| | - Jin Sook Jeong
- Department of Pathology and Immune-network Pioneer Research Center, Dong-A University College of Medicine, Busan 602-714, Republic of Korea
| | - Seong-Wook Lee
- R&D Center, Rznomics, Inc., Seongnam 13486, Republic of Korea.,Department of Life Convergence, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea
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5
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Seo MJ, Park JH, Lee KC, Lee YJ, Lee TS, Choi TH, Lee SW, Kim KI, Kang JH. Small Animal PET Imaging of hTERT RNA-Targeted HSV1-tk Gene Expression with Trans-Splicing Ribozyme. Cancer Biother Radiopharm 2019; 35:26-32. [PMID: 31746630 DOI: 10.1089/cbr.2019.2839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Background: Trans-splicing ribozymes (TSR) are useful anticancer agents targeting cancer-specific transcripts and replacing the RNA to induce anticancer gene expression specifically and selectively in cancer cells. Similar to other gene therapy methods, it is also important to evaluate the transgene expression for target specificity and ribozyme activity. Materials and Methods: In this study, the authors performed in vivo small animal positron emission tomography (PET) imaging and biodistribution assay to evaluate human telomerase reverse transcriptase (hTERT) RNA-targeting-specific TSR, which directs the expression of herpes simplex virus type 1 thymidine kinase (HSV1-tk) gene selectively in hTERT-positive tumors through targeted RNA replacement of the hTERT transcript. Results: The hTERT RNA-targeted HSV1-tk expression with TSR was monitored by PET imaging with 124I labeled 2'-fluoro-2'-deoxy-1-β-D-arabinofuranosyl-5-iodouracil, which is one of the thymidine derivatives acting as substrates for HSV1-tk, in hTERT-positive tumor-bearing mice. Conclusions: Imaging of hTERT RNA-targeted HSV1-tk expression by TSR could be used in the development of advanced gene therapy using tumor-specific TSR.
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Affiliation(s)
- Min-Jung Seo
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Ju Hui Park
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Kyo Chul Lee
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Yong Jin Lee
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Tae Sup Lee
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Tae Hyun Choi
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Seong-Wook Lee
- Department of Integrated Life Sciences, Research Institute of Advanced Omics, Dankook University, Yongin, Korea
| | - Kwang Il Kim
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Joo Hyun Kang
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
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Lee CH, Han SR, Lee SW. Group I Intron-Based Therapeutics Through Trans-Splicing Reaction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 159:79-100. [PMID: 30340790 DOI: 10.1016/bs.pmbts.2018.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In 1982, the Cech group discovered that an intron structure in an rRNA precursor of Tetrahymena thermophila is sufficient to complete splicing without assistance from proteins. This was the first moment that scientists recognized RNAs can have catalytic activities derived from their own unique three-dimensional structures and thus play more various roles in biological processes than thought before. Several additional catalytic RNAs, called ribozymes, were subsequently identified in nature followed by intense studies to reveal their mechanisms of action and to engineer them for use in fields such as molecular cell biology, therapeutics, imaging, etc. Naturally occurring RNA-targeting ribozymes can be broadly classified into two categories by their abilities: Self-cleavage and self-splicing. Since ribozymes use base-pairing to recognize cleavage sites, identification of the catalytic center of naturally occurring ribozymes enables to engineer from "self" to "trans" acting ones which has accelerated to design and use ribozyme as valuable tools in gene therapy fields. Especially, group I intron-based trans-splicing ribozyme has unique property to use as a gene therapeutic agent. It can destroy and simultaneously repair (and/or reprogram) target RNAs to yield the desired therapeutic RNAs, maintaining endogenous spatial and temporal gene regulation of target RNAs. There have been progressive improvements in trans-splicing ribozymes and successful applications of these elements in gene therapy and molecular imaging approaches for various pathogenic conditions. In this chapter, current status of trans-splicing ribozyme therapeutics, focusing on Tetrahymena group I intron-based ribozymes, and their future prospects will be discussed.
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Affiliation(s)
- Chang Ho Lee
- Department of Integrated Life Sciences, Dankook University, Yongin, Republic of Korea
| | | | - Seong-Wook Lee
- Department of Integrated Life Sciences, Dankook University, Yongin, Republic of Korea; Rznomics Inc., Gwangju, Republic of Korea.
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7
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Liemberger B, Piñón Hofbauer J, Wally V, Arzt C, Hainzl S, Kocher T, Murauer EM, Bauer JW, Reichelt J, Koller U. RNA Trans-Splicing Modulation via Antisense Molecule Interference. Int J Mol Sci 2018. [PMID: 29518954 PMCID: PMC5877623 DOI: 10.3390/ijms19030762] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In recent years, RNA trans-splicing has emerged as a suitable RNA editing tool for the specific replacement of mutated gene regions at the pre-mRNA level. Although the technology has been successfully applied for the restoration of protein function in various genetic diseases, a higher trans-splicing efficiency is still desired to facilitate its clinical application. Here, we describe a modified, easily applicable, fluorescence-based screening system for the generation and analysis of antisense molecules specifically capable of improving the RNA reprogramming efficiency of a selected KRT14-specific RNA trans-splicing molecule. Using this screening procedure, we identified several antisense RNAs and short rationally designed oligonucleotides, which are able to increase the trans-splicing efficiency. Thus, we assume that besides the RNA trans-splicing molecule, short antisense molecules can act as splicing modulators, thereby increasing the trans-splicing efficiency to a level that may be sufficient to overcome the effects of certain genetic predispositions, particularly those associated with dominantly inherited diseases.
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Affiliation(s)
- Bernadette Liemberger
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.
| | - Josefina Piñón Hofbauer
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.
| | - Verena Wally
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.
| | - Claudia Arzt
- Laboratory for Immunological and Molecular Cancer Research, Department of Internal Medicine III with Hematology, Medical Oncology, Hemostaseology, Infectious Diseases, Rheumatology, Oncologic Center, Paracelsus Medical University, 5020 Salzburg, Austria.
| | - Stefan Hainzl
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.
| | - Thomas Kocher
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.
| | - Eva M Murauer
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.
| | - Johann W Bauer
- Department of Dermatology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.
| | - Julia Reichelt
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.
| | - Ulrich Koller
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.
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8
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Lee CH, Han SR, Lee SW. Therapeutic applications of group I intron-based trans-splicing ribozymes. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1466. [PMID: 29383855 DOI: 10.1002/wrna.1466] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 12/10/2017] [Accepted: 12/14/2017] [Indexed: 12/21/2022]
Abstract
Since the breakthrough discovery of catalytic RNAs (ribozymes) in the early 1980s, valuable ribozyme-based gene therapies have been developed for incurable diseases ranging from genetic disorders to viral infections and cancers. Ribozymes can be engineered and used to downregulate or repair pathogenic genes via RNA cleavage mediated by trans-cleaving ribozymes or repair and reprograming mediated by trans-splicing ribozymes, respectively. Uniquely, trans-splicing ribozymes can edit target RNAs via simultaneous destruction and repair (and/or reprograming) to yield the desired therapeutic RNAs, thus selectively inducing therapeutic gene activity in cells expressing the target RNAs. In contrast to traditional gene therapy approaches, such as simple addition of therapeutic transgenes or inhibition of disease-causing genes, the selective repair and/or reprograming abilities of trans-splicing ribozymes in target RNA-expressing cells facilitates the maintenance of endogenous spatial and temporal gene regulation and reduction of disease-associated transcript expression. In molecular imaging technologies, trans-splicing ribozymes can be used to reprogram specific RNAs in living cells and organisms by the 3'-tagging of reporter RNAs. The past two decades have seen progressive improvements in trans-splicing ribozymes and the successful application of these elements in gene therapy and molecular imaging approaches for various pathogenic conditions, such as genetic, infectious, and malignant disease. This review provides an overview of the current status of trans-splicing ribozyme therapeutics, focusing on Tetrahymena group I intron-based ribozymes, and their future prospects. This article is categorized under: RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Chang Ho Lee
- Department of Integrated Life Sciences, Dankook University, Yongin, Republic of Korea
| | - Seung Ryul Han
- Department of Integrated Life Sciences, Dankook University, Yongin, Republic of Korea
| | - Seong-Wook Lee
- Department of Integrated Life Sciences, Dankook University, Yongin, Republic of Korea
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9
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Kim SJ, Kim JH, Yang B, Jeong JS, Lee SW. Specific and Efficient Regression of Cancers Harboring KRAS Mutation by Targeted RNA Replacement. Mol Ther 2017; 25:356-367. [PMID: 28153088 DOI: 10.1016/j.ymthe.2016.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 11/01/2016] [Accepted: 11/11/2016] [Indexed: 12/30/2022] Open
Abstract
Mutations in the KRAS gene, which persistently activate RAS function, are most frequently found in many types of human cancers. Here, we proposed and verified a new approach against cancers harboring the KRAS mutation with high cancer selectivity and efficient anti-cancer effects based on targeted RNA replacement. To this end, trans-splicing ribozymes from Tetrahymena group I intron were developed, which can specifically target and reprogram the mutant KRAS G12V transcript to induce therapeutic gene activity in cells. Adenoviral vectors containing the specific ribozymes with downstream suicide gene were constructed and then infection with the adenoviruses specifically downregulated KRAS G12V expression and killed KRAS G12V-harboring cancer cells additively upon pro-drug treatment, but it did not affect the growth of wild-type KRAS-expressing cells. Minimal liver toxicity was noted when the adenoviruses were administered systemically in vivo. Importantly, intratumoral injection of the adenoviruses with pro-drug treatment specifically and significantly impeded the growth of xenografted tumors harboring KRAS G12V through a trans-splicing reaction with the target RNA. In contrast, xenografted tumors harboring wild-type KRAS were not affected by the adenoviruses. Therefore, RNA replacement with a mutant KRAS-targeting trans-splicing ribozyme is a potentially useful therapeutic strategy to combat tumors harboring KRAS mutation.
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Affiliation(s)
- Sung Jin Kim
- Department of Integrated Life Sciences, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea
| | - Ju Hyun Kim
- Department of Integrated Life Sciences, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea
| | - Bitna Yang
- Department of Integrated Life Sciences, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea
| | - Jin-Sook Jeong
- Department of Pathology and Immune-network Pioneer Research Center, Dong-A University College of Medicine, Busan 49202, Republic of Korea
| | - Seong-Wook Lee
- Department of Integrated Life Sciences, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Republic of Korea.
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Design and Experimental Evolution of trans-Splicing Group I Intron Ribozymes. Molecules 2017; 22:molecules22010075. [PMID: 28045452 PMCID: PMC6155759 DOI: 10.3390/molecules22010075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/27/2016] [Accepted: 12/29/2016] [Indexed: 12/31/2022] Open
Abstract
Group I intron ribozymes occur naturally as cis-splicing ribozymes, in the form of introns that do not require the spliceosome for their removal. Instead, they catalyze two consecutive trans-phosphorylation reactions to remove themselves from a primary transcript, and join the two flanking exons. Designed, trans-splicing variants of these ribozymes replace the 3′-portion of a substrate with the ribozyme’s 3′-exon, replace the 5′-portion with the ribozyme’s 5′-exon, or insert/remove an internal sequence of the substrate. Two of these designs have been evolved experimentally in cells, leading to variants of group I intron ribozymes that splice more efficiently, recruit a cellular protein to modify the substrate’s gene expression, or elucidate evolutionary pathways of ribozymes in cells. Some of the artificial, trans-splicing ribozymes are promising as tools in therapy, and as model systems for RNA evolution in cells. This review provides an overview of the different types of trans-splicing group I intron ribozymes that have been generated, and the experimental evolution systems that have been used to improve them.
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11
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Kim YH, Kim KT, Lee SJ, Hong SH, Moon JY, Yoon EK, Kim S, Kim EO, Kang SH, Kim SK, Choi SI, Goh SH, Kim D, Lee SW, Ju MH, Jeong JS, Kim IH. Image-aided Suicide Gene Therapy Utilizing Multifunctional hTERT-targeting Adenovirus for Clinical Translation in Hepatocellular Carcinoma. Am J Cancer Res 2016; 6:357-68. [PMID: 26909111 PMCID: PMC4737723 DOI: 10.7150/thno.13621] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/21/2015] [Indexed: 02/06/2023] Open
Abstract
Trans-splicing ribozyme enables to sense and reprogram target RNA into therapeutic transgene and thereby becomes a good sensing device for detection of cancer cells, judging from transgene expression. Previously we proposed PEPCK-Rz-HSVtk (PRT), hTERT targeting trans-splicing ribozyme (Rz) driven by liver-specific promoter phosphoenolpyruvate carboxykinase (PEPCK) with downstream suicide gene, herpes simplex virus thymidine kinase (HSVtk) for hepatocellular carcinoma (HCC) gene therapy. Here, we describe success of a re-engineered adenoviral vector harboring PRT in obtaining greater antitumor activity with less off-target effect for clinical application as a theranostics. We introduced liver-selective apolipoprotein E (ApoE) enhancer to the distal region of PRT unit to augment activity and liver selectivity of PEPCK promoter, and achieved better transduction into liver cancer cells by replacement of serotype 35 fiber knob on additional E4orf1-4 deletion of E1&E3-deleted serotype 5 back bone. We demonstrated that our refined adenovirus harboring PEPCK/ApoE-Rz-HSVtk (Ad-PRT-E) achieved great anti-tumor efficacy and improved ability to specifically target HCC without damaging normal hepatocytes. We also showed noninvasive imaging modalities were successfully employed to monitor both how well a therapeutic gene (HSVtk) was expressed inside tumor and how effectively a gene therapy took an action in terms of tumor growth. Collectively, this study suggests that the advanced therapeutic adenoviruses Ad-PRT-E and its image-aided evaluation system may lead to the powerful strategy for successful clinical translation and the development of clinical protocols for HCC therapy.
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12
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Carter JR, Taylor S, Fraser TS, Kucharski CA, Dawson JL, Fraser MJ. Suppression of the Arboviruses Dengue and Chikungunya Using a Dual-Acting Group-I Intron Coupled with Conditional Expression of the Bax C-Terminal Domain. PLoS One 2015; 10:e0139899. [PMID: 26580561 PMCID: PMC4651551 DOI: 10.1371/journal.pone.0139899] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 09/18/2015] [Indexed: 11/19/2022] Open
Abstract
In portions of South Asia, vectors and patients co-infected with dengue (DENV) and chikungunya (CHIKV) are on the rise, with the potential for this occurrence in other regions of the world, for example the United States. Therefore, we engineered an antiviral approach that suppresses the replication of both arboviruses in mosquito cells using a single antiviral group I intron. We devised unique configurations of internal, external, and guide sequences that permit homologous recognition and splicing with conserved target sequences in the genomes of both viruses using a single trans-splicing Group I intron, and examined their effectiveness to suppress infections of DENV and CHIKV in mosquito cells when coupled with a proapoptotic 3' exon, ΔN Bax. RT-PCR demonstrated the utility of these introns in trans-splicing the ΔN Bax sequence downstream of either the DENV or CHIKV target site in transformed Aedes albopictus C6/36 cells, independent of the order in which the virus specific targeting sequences were inserted into the construct. This trans-splicing reaction forms DENV or CHIKV ΔN Bax RNA fusions that led to apoptotic cell death as evidenced by annexin V staining, caspase, and DNA fragmentation assays. TCID50-IFA analyses demonstrate effective suppression of DENV and CHIKV infections by our anti-arbovirus group I intron approach. This represents the first report of a dual-acting Group I intron, and demonstrates that we can target DENV and CHIKV RNAs in a sequence specific manner with a single, uniquely configured CHIKV/DENV dual targeting group I intron, leading to replication suppression of both arboviruses, and thus providing a promising single antiviral for the transgenic suppression of multiple arboviruses.
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Affiliation(s)
- James R. Carter
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Samantha Taylor
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Tresa S. Fraser
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Cheryl A. Kucharski
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - James L. Dawson
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Malcolm J. Fraser
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- * E-mail:
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13
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Lee CH, Han SR, Lee SW. Therapeutic Applications of Aptamer-Based Riboswitches. Nucleic Acid Ther 2015; 26:44-51. [PMID: 26539634 DOI: 10.1089/nat.2015.0570] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Aptamers bind to their targets with high affinity and specificity through structure-based complementarity, instead of sequence complementarity that is used by most of the oligonucleotide-based therapeutics. This property has been exploited in using aptamers as multifunctional therapeutic units, by attaching them to therapeutic drugs, nanoparticles, or imaging agents, or as direct molecular decoys for inducing loss-of-function or gain-of-function of targets. One of the most interesting fields of aptamer application is their development as molecular sensors to regulate artificial riboswitches. Naturally, the riboswitches sense small-molecule metabolites and respond by regulating the expression of the corresponding metabolic genes. Riboswitches are cis-acting RNA structures that consist of the sensing (aptamer) and the regulating (expression platform) domains. In principle, diverse riboswitches can be engineered and applied to control different steps of gene expression in bacterial species as well as eukaryotes, by simply replacing aptamers against various endogenous and/or exogenous targets. Although these engineered aptamer-based riboswitches are recently gaining attention, it is clear that aptamer-based riboswitches have a potential for next-generation therapeutics against various diseases because of their controllability, specificity, and modularity in regulating gene expression through various cellular processes, including transcription, splicing, stability, RNA interference, and translation. In this review, we provide a summary of the recently developed and engineered aptamer-based riboswitches focusing on their therapeutic availability and further discuss their clinical potential.
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Affiliation(s)
- Chang Ho Lee
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, and Research Institute of Advanced Omics, Dankook University , Yongin, Republic of Korea
| | - Seung Ryul Han
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, and Research Institute of Advanced Omics, Dankook University , Yongin, Republic of Korea
| | - Seong-Wook Lee
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, and Research Institute of Advanced Omics, Dankook University , Yongin, Republic of Korea
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Targeted Regression of Hepatocellular Carcinoma by Cancer-Specific RNA Replacement through MicroRNA Regulation. Sci Rep 2015; 5:12315. [PMID: 26189916 PMCID: PMC4507181 DOI: 10.1038/srep12315] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 06/26/2015] [Indexed: 01/06/2023] Open
Abstract
Hepatocellular carcinoma (HCC) has a high fatality rate and limited therapeutic options with side effects and low efficacy. Here, we proposed a new anti-HCC approach based on cancer-specific post-transcriptional targeting. To this end, trans-splicing ribozymes from Tetrahymena group I intron were developed, which can specifically induce therapeutic gene activity through HCC-specific replacement of telomerase reverse transcriptase (TERT) RNA. To circumvent side effects due to TERT expression in regenerating liver tissue, liver-specific microRNA-regulated ribozymes were constructed by incorporating complementary binding sites for the hepatocyte-selective microRNA-122a (miR-122a), which is down-regulated in HCC. The ribozyme activity in vivo was assessed in mouse models orthotopically implanted with HCC. Systemic administration of adenovirus encoding the developed ribozymes caused efficient anti-cancer effect and the least hepatotoxicity with regulation of ribozyme expression by miR-122a in both xenografted and syngeneic orthotopic murine model of multifocal HCC. Of note, the ribozyme induced local and systemic antitumor immunity, thereby completely suppressing secondary tumor challenge in the syngeneic mouse. The cancer specific trans-splicing ribozyme system, which mediates tissue-specific microRNA-regulated RNA replacement, provides a clinically relevant, safe, and efficient strategy for HCC treatment.
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Kim J, Jeong S, Kertsburg A, Soukup GA, Lee SW. Conditional and target-specific transgene induction through RNA replacement using an allosteric trans-splicing ribozyme. ACS Chem Biol 2014; 9:2491-5. [PMID: 25265474 DOI: 10.1021/cb500567v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gene therapeutic approaches are needed that can simultaneously induce the well-controlled expression of therapeutic genes and suppress the expression of disease-causing genes for maximization of their efficacy. To address this challenge, we designed an allosteric ribozyme that comprises a Tetrahymena group I-based trans-splicing ribozyme as an active domain for RNA replacement, a small molecule-specific RNA aptamer as a sensor domain, and a communication module as an active transfer domain. The effectiveness of this approach was assessed by constructing various ribozymes in combination with a theophylline-binding aptamer to identify an allosteric ribozyme, which is controlled by theophylline both in vitro and in cells. Moreover, we constructed adenoviral vectors encoding the ribozymes and validated allosteric regulation of trans-gene expression via theophylline-dependent RNA replacement in target RNA-expressing cells. Results demonstrate that an allosteric trans-splicing ribozyme is an applicable RNA-based framework for engineering external ligand-controlled gene expression regulatory systems that exhibit adjustable regulation, design modularity, and target specificity.
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Affiliation(s)
- Juhyun Kim
- Department
of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin, Republic of Korea
| | - Seonyeong Jeong
- Department
of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin, Republic of Korea
| | - Alexis Kertsburg
- Department
of Biomedical Sciences, School of Medicine, Creighton University, Omaha, Nebraska 68178, United States
| | - Garrett A. Soukup
- Department
of Biomedical Sciences, School of Medicine, Creighton University, Omaha, Nebraska 68178, United States
| | - Seong-Wook Lee
- Department
of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin, Republic of Korea
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Won YS, Jeong JS, Kim SJ, Ju MH, Lee SW. Targeted anticancer effect through microRNA-181a regulated tumor-specific hTERT replacement. Cancer Lett 2014; 356:918-28. [PMID: 25444904 DOI: 10.1016/j.canlet.2014.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/01/2014] [Accepted: 11/04/2014] [Indexed: 01/11/2023]
Abstract
We previously generated a group I intron-based ribozyme that can reprogram human telomerase reverse transcriptase (hTERT) RNA to stimulate transgene activity in cancer cells expressing the target RNA via an accurate and specific trans-splicing reaction. One of the major concerns of the hTERT RNA targeting anti-cancer approach is the potential side effects to hTERT(+) hematopoietic stem cell-derived blood cells. Thus, here we modified the ribozyme by inserting target sites against microRNA-181a, which is a blood cell-specific microRNA, downstream of its 3' exon. The specificity of transgene induction and anticancer activity in hTERT(+) cancer cells improved significantly with the modified ribozyme, resulting in selective targeting of hTERT(+) cancer cells, but not hematopoietic cells even if they are hTERT-positive. Importantly, the trans-splicing reaction of the microRNA-regulated ribozyme worked equally well in a nude mouse model of hepatocarcinoma-derived intrasplenic carcinomatosis, inducing highly specific expression of a therapeutic transgene and efficiently regressing hTERT-positive liver tumors with minimal liver toxicity when systemically delivered with an adenoviral vector encoding the ribozyme. These results suggest that a combined approach of microRNA regulation with targeted RNA replacement is more useful for effective anti-cancer treatment.
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Affiliation(s)
- You-Sub Won
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, and Research Institute of Advanced Omics, Dankook University, Yongin, Republic of Korea
| | - Jin-Sook Jeong
- Department of Pathology and Medical Research Center for Cancer Molecular Therapy, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Sung Jin Kim
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, and Research Institute of Advanced Omics, Dankook University, Yongin, Republic of Korea
| | - Mi Ha Ju
- Department of Pathology and Medical Research Center for Cancer Molecular Therapy, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Seong-Wook Lee
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, and Research Institute of Advanced Omics, Dankook University, Yongin, Republic of Korea.
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Goh AR, Shin SP, Jung NR, Ryu CH, Eom HS, Lee JH, Choi K, Lee SJ, Jung YS. Low-dose cisplatin converts the tumor microenvironment into a permissive state for HSVtk-induced antitumor immunity in HPV16-related tonsillar carcinoma. Cancer Lett 2014; 356:743-50. [PMID: 25449436 DOI: 10.1016/j.canlet.2014.10.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 02/05/2023]
Abstract
An adenovirus harboring the HSV thymidine kinase (HSVtk) gene under the regulation of a trans-splicing ribozyme that targets telomerase is cytotoxic to cancer cells because it inhibits DNA replication (Ad5mTR). Furthermore, it induces anti-tumor immunity by activating cytotoxic T cells. Because multiple chemotherapeutic agents also activate cytotoxic T-cell immunity during the direct killing process of tumor cells, we herein explored whether low-dose cisplatin could synergize with cytotoxic Ad5mTR to potentiate its therapeutic effect by boosting anti-tumor immunity in a murine HPV16-associated tonsillar carcinoma model. Tumor regression was enhanced when low-dose (1 mg/kg) cisplatin was added to suicide gene therapy using Ad5mTR. Meanwhile, 1 mg/kg cisplatin alone had no tumor-suppressive effects and did not result in any systemic toxicity. Thus, cisplatin along with Ad5mTR improved tumor clearance by increasing the number of E7-specific CD8+ T cells. Specifically, analysis of the tumors and lymph nodes supported improved immune clearance by increasing the number of E7-specific CD8+ T cells inside tumors (40%, P < 0.05) as a result of the combination of suicide gene and cisplatin therapy. These results suggest that a low dose of cisplatin potentiates CD8+ T-cell-mediated anti-tumor immunity, and its addition to the HSVtk-based adenovirus results in additional therapeutic benefits for HPV16-positive head and neck cancer patients.
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Affiliation(s)
| | | | | | - Chang-Hwan Ryu
- Specific Organs Cancer Branch, Department of Otolaryngology
| | - Hyeon Seok Eom
- Hematologic-Oncology, Research Institute & Hospital, National Cancer Center, Goyang, South Korea
| | - John H Lee
- Sanford Cancer Research Center, Sanford ENT - Head and Neck Surgery, Sioux Falls, South Dakota
| | - Kyungho Choi
- Seoul National University College of Medicine, Seoul, South Korea
| | | | - Yuh-S Jung
- Specific Organs Cancer Branch, Department of Otolaryngology.
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Kim SJ, Lee SW. Selective expression of transgene using hypoxia-inducible trans-splicing group I intron ribozyme. J Biotechnol 2014; 192 Pt A:22-7. [PMID: 25312327 DOI: 10.1016/j.jbiotec.2014.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/12/2014] [Accepted: 10/01/2014] [Indexed: 11/16/2022]
Abstract
Low oxygen conditions, termed hypoxia, can affect cell survivals. Cells may adapt to hypoxic conditions through hypoxia response elements (HRE) such as erythropoietin enhancer or phosphoglycerate kinase element. Hypoxic conditions usually appear in solid tumors, and can cause resistance to radiotherapy or chemotherapy. In this study, a genetic approach based upon Tetrahymena group I ribozyme was developed, which can address the challenges induced by a hypoxic microenvironment. To this end, human telomerase reverse transcriptase (hTERT) targeting trans-splicing ribozymes whose expression and activity were induced by HRE under hypoxia were constructed. Luciferase reporter assay showed induction of the transgene to increase due to the hypoxia-inducible ribozymes through a specific trans-splicing reaction in hTERT-expressing cells under hypoxic conditions. Increase in the transgene expression was mainly due to the increased trans-splicing reaction through a concurrent increase of the ribozyme expression level. Moreover, hypoxia-inducible ribozyme with herpes simplex virus thymidine kinase as the 3'exon effectively induced cell death when treated with ganciclovir under both hypoxic and normoxic conditions. These results indicated that the trans-splicing ribozyme could be a target-specific and efficacious anti-cancer tool to overcome resistance to radio- and chemotherapy under hypoxic conditions.
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Affiliation(s)
- Sung Jin Kim
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, 126, Jukjeon-dong, Suji-gu, Yongin 448-701, Republic of Korea
| | - Seong-Wook Lee
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, 126, Jukjeon-dong, Suji-gu, Yongin 448-701, Republic of Korea.
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Carter JR, Keith JH, Fraser TS, Dawson JL, Kucharski CA, Horne KM, Higgs S, Fraser MJ. Effective suppression of dengue virus using a novel group-I intron that induces apoptotic cell death upon infection through conditional expression of the Bax C-terminal domain. Virol J 2014; 11:111. [PMID: 24927852 PMCID: PMC4104402 DOI: 10.1186/1743-422x-11-111] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/20/2014] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Approximately 100 million confirmed infections and 20,000 deaths are caused by Dengue virus (DENV) outbreaks annually. Global warming and rapid dispersal have resulted in DENV epidemics in formally non-endemic regions. Currently no consistently effective preventive measures for DENV exist, prompting development of transgenic and paratransgenic vector control approaches. Production of transgenic mosquitoes refractory for virus infection and/or transmission is contingent upon defining antiviral genes that have low probability for allowing escape mutations, and are equally effective against multiple serotypes. Previously we demonstrated the effectiveness of an anti-viral group I intron targeting U143 of the DENV genome in mediating trans-splicing and expression of a marker gene with the capsid coding domain. In this report we examine the effectiveness of coupling expression of ΔN Bax to trans-splicing U143 intron activity as a means of suppressing DENV infection of mosquito cells. RESULTS Targeting the conserved DENV circularization sequence (CS) by U143 intron trans-splicing activity appends a 3' exon RNA encoding ΔN Bax to the capsid coding region of the genomic RNA, resulting in a chimeric protein that induces premature cell death upon infection. TCID50-IFA analyses demonstrate an enhancement of DENV suppression for all DENV serotypes tested over the identical group I intron coupled with the non-apoptotic inducing firefly luciferase as the 3' exon. These cumulative results confirm the increased effectiveness of this αDENV-U143-ΔN Bax group I intron as a sequence specific antiviral that should be useful for suppression of DENV in transgenic mosquitoes. Annexin V staining, caspase 3 assays, and DNA ladder observations confirm DCA-ΔN Bax fusion protein expression induces apoptotic cell death. CONCLUSION This report confirms the relative effectiveness of an anti-DENV group I intron coupled to an apoptosis-inducing ΔN Bax 3' exon that trans-splices conserved sequences of the 5' CS region of all DENV serotypes and induces apoptotic cell death upon infection. Our results confirm coupling the targeted ribozyme capabilities of the group I intron with the generation of an apoptosis-inducing transcript increases the effectiveness of infection suppression, improving the prospects of this unique approach as a means of inducing transgenic refractoriness in mosquitoes for all serotypes of this important disease.
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Affiliation(s)
| | | | | | | | | | | | | | - Malcolm J Fraser
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana 46556, USA.
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20
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Abstract
One of the major concerns with regard to successful cancer gene therapy is to enhance both efficacy and safety. Gene targeting may represent an attractive tool to combat cancer cells without damage to normal cells. Here, we introduce a tumor-targeting approach with the Tetrahymena group I intron-based trans-splicing ribozyme, which cleaves target RNA and trans-ligate an exon tagged at the end of the ribozyme onto the downstream U nucleotide of the cleaved target RNA. We develop a specific trans-splicing ribozyme that can target and reprogram human cytoskeleton-associate protein 2 (hCKAP2)-encoding RNA to trigger therapeutic transgene herpes simplex virus thymidine kinase (HSVtk) selectively in cancer cells that express the RNA. Adenoviral vectors encoding the hCKAP2-specific trans-splicing ribozyme are constructed for in vivo delivery into either subcutaneous tumor xenograft or orthotopically multifocal hepatocarcinoma. We present analyses of the efficacy of the recombinant adenoviral vectors in terms of cancer retardation, target RNA and cell specificity, and in vivo toxicity.
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Kim YH, Moon JY, Kim EO, Lee SJ, Kang SH, Kim SK, Heo K, Lee Y, Kim H, Kim KT, Kim D, Song MS, Lee SW, Lee Y, Koh SS, Kim IH. Efficient targeting and tumor retardation effect of pancreatic adenocarcinoma up-regulated factor (PAUF)-specific RNA replacement in pancreatic cancer mouse model. Cancer Lett 2013; 344:223-31. [PMID: 24189457 DOI: 10.1016/j.canlet.2013.10.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/19/2013] [Accepted: 10/27/2013] [Indexed: 12/15/2022]
Abstract
The soluble protein pancreatic adenocarcinoma up-regulated factor (PAUF) plays an important role in pancreatic tumor progression and has begun to attract attention as a therapeutic target for pancreatic cancer. We herein present PAUF RNA-targeting gene therapy strategies with both targeting and therapeutic function using trans-splicing ribozyme (TSR) in pancreatic cancer. We developed adenoviral PAUF-targeting TSR (Rz) containing a PAUF-specific internal guide sequence (IGS) determined by library screening. This Rz harbors suicide gene, herpes simplex virus thymidine kinase (HSV-tk) or firefly luciferase (Luc) as a transgene for 3' exon replacement of PAUF RNAs. Ad-Rz-TK, Rz harboring the HSV-tk, showed significant inhibition of tumor growth in vivo as well as PAUF-dependent cell death in vitro via a successful trans-splicing reaction. Selective induction of Rz-controlled transgene in PAUF-expressing pancreatic cancer was confirmed through noninvasive in vivo imaging; a luminescence signal from Rz harboring Luc (Ad-Rz-Luc) was detectable only in pancreatic tumor sites, not in normal mice. In addition, a [(125)I] FIAU signal reflecting thymidine kinase expression through SPECT and ex vivo biodistribution was co-localized with the tumor sites when we treated with Ad-Rz-TK in orthotopic xenograft model. Taken together, these results imply that PAUF-targeting TSR can contribute to successful targeted gene therapy for pancreatic cancer.
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Affiliation(s)
- Yun-Hee Kim
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea.
| | - Ju Young Moon
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Eun-Ok Kim
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Sang-Jin Lee
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Se Hun Kang
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Seok Ki Kim
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Kyun Heo
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Yusun Lee
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Hana Kim
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Kyung-Tae Kim
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Daehong Kim
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea
| | - Min Sun Song
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Suji-Gu, Yongin, Republic of Korea
| | - Seoung-Wook Lee
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Suji-Gu, Yongin, Republic of Korea
| | - Yangsoon Lee
- Therapeutic Antibody Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Sang Seok Koh
- Therapeutic Antibody Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - In-Hoo Kim
- Research Institute & Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea.
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Lee SJ, Kim SJ, Seo HH, Shin SP, Kim D, Park CS, Kim KT, Kim YH, Jeong JS, Kim IH. Over-expression of miR-145 enhances the effectiveness of HSVtk gene therapy for malignant glioma. Cancer Lett 2012; 320:72-80. [PMID: 22269208 DOI: 10.1016/j.canlet.2012.01.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 01/10/2012] [Accepted: 01/16/2012] [Indexed: 01/03/2023]
Abstract
This study attempts to combine two findings toward developing a rational strategy for improved therapy for glioma. One of the findings, made in this pre-clinical study, is that an hTERT-targeting ribozyme-controlled HSVtk gene (hTERT.Rz.HSVtk) exerts anti-tumor effects. The second observation is that the over-expression of a small noncoding RNA, miR-145, causes down-regulation of metastasis-related genes, such as PLAUR, SPOCK3, ADAM22, SLC7A5 and FASCN1. While blocking in vivo tumor growth only slightly, over-expression of miR-145 significantly inhibits both the migration and invasion of U87MG/U373MG glioma cells. We hypothesized that a simultaneous adenoviral-mediated over-expression of miR-145 might enhance the anti-tumor effects of hTERT.Rz.HSVtk and that a combination therapy with miR-145 and the HSVtk gene would be an effective approach for treating glioma. We tested this by developing adenoviral vectors that over-express miR-145 under the CMV promoter and employing them in combination with hTERT.Rz.HSVtk expression, both in vitro and in vivo in animal studies. We found that the adenovirus Ad5CMV.Rz.HSVtk.miR145 harboring an HSVtk expression cassette plus miR-145 produced prolonged survival benefits compared to administration of Ad5CMV.Rz.HSVtk or Ad5CMV.miR-145 alone. This study demonstrates that combination therapy using the hTERT.Rz.HSVtk gene together with miR-145 over-expression produces enhanced anti-tumor effects compared to that resulting from hTERT.Rz.HSVtk gene therapy alone.
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Affiliation(s)
- Sang-Jin Lee
- Genitourinary Cancer Branch, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, Republic of Korea.
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Eukaryotic expression vectors bearing genes encoding cytotoxic proteins for cancer gene therapy. Plasmid 2012; 68:69-85. [PMID: 22613563 DOI: 10.1016/j.plasmid.2012.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 02/11/2012] [Accepted: 05/09/2012] [Indexed: 01/03/2023]
Abstract
Cancer gene therapy is a promising direction for the treatment of cancer patients. A primary goal of all cancer therapies is to selectively target and kill tumour cells. Such therapies are administered via different approaches, including both viral and non-viral delivery; however, both methods have advantages and disadvantages. Transcriptional targeting enables genes encoding toxic proteins to be expressed directly in cancer cells. Numerous vectors have been created with the purpose of killing cancer cells, and some have successfully suppressed malignant tumours. Data concerning the function of vectors bearing genes that encode cytotoxic proteins under the control of different promoters, including tissue/tumour specific and constitutive promoters, is summarised here. This review focuses on vectors that bear genes encoding diphtheria toxin, Pseudomonas exotoxin A, caspases, gef, streptolysin, and melittin. Data describing the efficacy of such vectors have been summarised. Notably, there are vectors that killed cancer cell lines originating from the same type of cancer with differential efficiency. Thus, there is differential inhibition of cancer cell growth dependent on the cell line. In this review, the constructs employing genes whose expression induces cell death and the efficiency with which they suppress cancer cell growth will be summarised.
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Selective regression of cancer cells expressing a splicing variant of AIMP2 through targeted RNA replacement by trans-splicing ribozyme. J Biotechnol 2012; 158:44-9. [DOI: 10.1016/j.jbiotec.2012.01.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 12/21/2011] [Accepted: 01/10/2012] [Indexed: 11/20/2022]
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25
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Meluzzi D, Olson KE, Dolan GF, Arya G, Müller UF. Computational prediction of efficient splice sites for trans-splicing ribozymes. RNA (NEW YORK, N.Y.) 2012; 18:590-602. [PMID: 22274956 PMCID: PMC3285945 DOI: 10.1261/rna.029884.111] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 12/02/2011] [Indexed: 05/31/2023]
Abstract
Group I introns have been engineered into trans-splicing ribozymes capable of replacing the 3'-terminal portion of an external mRNA with their own 3'-exon. Although this design makes trans-splicing ribozymes potentially useful for therapeutic application, their trans-splicing efficiency is usually too low for medical use. One factor that strongly influences trans-splicing efficiency is the position of the target splice site on the mRNA substrate. Viable splice sites are currently determined using a biochemical trans-tagging assay. Here, we propose a rapid and inexpensive alternative approach to identify efficient splice sites. This approach involves the computation of the binding free energies between ribozyme and mRNA substrate. We found that the computed binding free energies correlate well with the trans-splicing efficiency experimentally determined at 18 different splice sites on the mRNA of chloramphenicol acetyl transferase. In contrast, our results from the trans-tagging assay correlate less well with measured trans-splicing efficiency. The computed free energy components suggest that splice site efficiency depends on the following secondary structure rearrangements: hybridization of the ribozyme's internal guide sequence (IGS) with mRNA substrate (most important), unfolding of substrate proximal to the splice site, and release of the IGS from the 3'-exon (least important). The proposed computational approach can also be extended to fulfill additional design requirements of efficient trans-splicing ribozymes, such as the optimization of 3'-exon and extended guide sequences.
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Affiliation(s)
- Dario Meluzzi
- Department of Chemistry and Biochemistry, University of California, San Diego, California 92093, USA
- Department of NanoEngineering, University of California, San Diego, California 92093, USA
| | - Karen E. Olson
- Department of Chemistry and Biochemistry, University of California, San Diego, California 92093, USA
| | - Gregory F. Dolan
- Department of Chemistry and Biochemistry, University of California, San Diego, California 92093, USA
| | - Gaurav Arya
- Department of NanoEngineering, University of California, San Diego, California 92093, USA
| | - Ulrich F. Müller
- Department of Chemistry and Biochemistry, University of California, San Diego, California 92093, USA
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26
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Olson KE, Müller UF. An in vivo selection method to optimize trans-splicing ribozymes. RNA (NEW YORK, N.Y.) 2012; 18:581-589. [PMID: 22274958 PMCID: PMC3285944 DOI: 10.1261/rna.028472.111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 12/01/2011] [Indexed: 05/31/2023]
Abstract
Group I intron ribozymes can repair mutated mRNAs by replacing the 3'-terminal portion of the mRNA with their own 3'-exon. This trans-splicing reaction has the potential to treat genetic disorders and to selectively kill cancer cells or virus-infected cells. However, these ribozymes have not yet been used in therapy, partially due to a low in vivo trans-splicing efficiency. Previous strategies to improve the trans-splicing efficiencies focused on designing and testing individual ribozyme constructs. Here we describe a method that selects the most efficient ribozymes from millions of ribozyme variants. This method uses an in vivo rescue assay where the mRNA of an inactivated antibiotic resistance gene is repaired by trans-splicing group I intron ribozymes. Bacterial cells that express efficient trans-splicing ribozymes are able to grow on medium containing the antibiotic chloramphenicol. We randomized a 5'-terminal sequence of the Tetrahymena thermophila group I intron and screened a library with 9 × 10⁶ ribozyme variants for the best trans-splicing activity. The resulting ribozymes showed increased trans-splicing efficiency and help the design of efficient trans-splicing ribozymes for different sequence contexts. This in vivo selection method can now be used to optimize any sequence in trans-splicing ribozymes.
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Affiliation(s)
- Karen E. Olson
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - Ulrich F. Müller
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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Kwon BS, Jeong JS, Won YS, Lee CH, Yoon KS, Hyung Jung M, Kim IH, Lee SW. Intracellular efficacy of tumor-targeting group I intron-based trans-splicing ribozyme. J Gene Med 2011; 13:89-100. [PMID: 21322101 DOI: 10.1002/jgm.1545] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Group I intron-based trans-splicing ribozyme, which can specifically reprogram human telomerase reverse transcriptase (hTERT) RNA, could be a useful tool for tumor-targeted gene therapy. In the present study, the therapeutic feasibility of this ribozyme was investigated by analyzing trans-splicing efficacy in vivo as well as in cells. METHODS We assessed transgene activation, degree of ribozyme expression, targeted hTERT mRNA level, or the level of trans-splicing products in hTERT(+) cells or in human tumor nodules xenografted in animals after ribozyme administration. RESULTS The activity and efficacy of the trans-splicing ribozyme in cells was dependent on the amount of endogenous hTERT mRNA and/or the accumulation of ribozyme RNA in cells. Intracellular activity of the ribozyme reached a plateau when no more targetable substrate mRNA was available or the ribozyme RNA level was fully saturated. In addition, the efficacy of ribozyme in xenografted tumor tissues was dependent on the dose of the delivered ribozyme-encoding adenoviral vector, indicating the potential of the ribozyme expression level as a determining factor for the in vivo efficacy of the trans-splicing ribozyme. On the basis of these results, we enhanced the intracellular ribozyme activity by increasing the ribozyme expression level transcriptionally and/or post-transcriptionally. CONCLUSIONS We analyzed ribozyme efficacy and determined the most influential factors of its trans-splicing reaction in mammalian cell lines as well as in vivo. The present study could provide insights into the optimization of the trans-splicing ribozyme-based RNA replacement approach to cancer treatment.
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Affiliation(s)
- Byung-Su Kwon
- Department of Molecular Biology, Dankook University, Yongin, Korea
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Ban G, Jeong JS, Kim A, Kim SJ, Han SY, Kim IH, Lee SW. Selective and efficient retardation of cancers expressing cytoskeleton-associated protein 2 by targeted RNA replacement. Int J Cancer 2011; 129:1018-29. [DOI: 10.1002/ijc.25988] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 01/21/2011] [Accepted: 02/02/2011] [Indexed: 11/10/2022]
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Carter JR, Keith JH, Barde PV, Fraser TS, Fraser MJ. Targeting of highly conserved Dengue virus sequences with anti-Dengue virus trans-splicing group I introns. BMC Mol Biol 2010; 11:84. [PMID: 21078188 PMCID: PMC3000392 DOI: 10.1186/1471-2199-11-84] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 11/15/2010] [Indexed: 11/11/2022] Open
Abstract
Background Dengue viruses (DENV) are one of the most important viral diseases in the world with approximately 100 million infections and 200,000 deaths each year. The current lack of an approved tetravalent vaccine and ineffective insecticide control measures warrant a search for alternatives to effectively combat DENV. The trans-splicing variant of the Tetrahymena thermophila group I intron catalytic RNA, or ribozyme, is a powerful tool for post-transcriptional RNA modification. The nature of the ribozyme and the predictability with which it can be directed makes it a powerful tool for modifying RNA in nearly any cell type without the need for genome-altering gene therapy techniques or dependence on native cofactors. Results Several anti-DENV Group I trans-splicing introns (αDENV-GrpIs) were designed and tested for their ability to target DENV-2 NGC genomes in situ. We have successfully targeted two different uracil bases on the positive sense genomic strand within the highly conserved 5'-3' cyclization sequence (CS) region common to all serotypes of DENV with our αDENV-GrpIs. Our ribozymes have demonstrated ability to specifically trans-splice a new RNA sequence downstream of the targeted site in vitro and in transfected insect cells as analyzed by firefly luciferase and RT-PCR assays. The effectiveness of these αDENV-GrpIs to target infecting DENV genomes is also validated in transfected or transformed Aedes mosquito cell lines upon infection with unattenuated DENV-2 NGC. Conclusions Analysis shows that our αDENV-GrpIs have the ability to effectively trans-splice the DENV genome in situ. Notably, these results show that the αDENV-GrpI 9v1, designed to be active against all forms of Dengue virus, effectively targeted the DENV-2 NGC genome in a sequence specific manner. These novel αDENV-GrpI introns provide a striking alternative to other RNA based approaches for the transgenic suppression of DENV in transformed mosquito cells and tissues.
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Affiliation(s)
- James R Carter
- Eck Institute for Global Health, Department of Biology, University of Notre Dame, Notre Dame, IN 46556, USA
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In vivo reprogramming of human telomerase reverse transcriptase (hTERT) by trans-splicing ribozyme to target tumor cells. Methods Mol Biol 2010; 629:307-21. [PMID: 20387158 DOI: 10.1007/978-1-60761-657-3_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Our understanding of RNA has evolved over the last 20 years from the initial concept that RNA is simply an intermediate in protein synthesis or a structural component maintaining and expressing genetic information. Subsequently, the non-coding RNAs have attracted huge interest and have been developed as therapeutic reagents as well as research tools. An example of RNA-based therapeutic application is the Tetrahymena group I intron-based trans-splicing ribozyme, which cleaves target RNA and trans-ligates an exon tagged at its 3' end onto the downstream U nucleotide of the targeted RNA. Here, we describe the specific trans-splicing ribozyme that can sense and reprogram human telomerase reverse transcriptase (hTERT)-encoding RNA. This ribozyme converts hTERT RNA to therapeutic transgene herpes simplex virus (HSV) thymidine kinase (tk) and exhibits cytotoxicity to various hTERT-expressing cancer cells. For use in cancer therapy, CMV promoter-driven hTERTRibozyme.HSVtk expression cassette is inserted into adenovirus genome and delivered into either subcutaneous or intraspleenic liver-metastasized xenograft. We present here an evaluation of the inhibitory effects of CMV.hTERTRibozyme.HSVtk on tumor growth.
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31
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Song MS, Lee SW. RNA Mapping of Mutant Myotonic Dystrophy Protein Kinase 3'-Untranslated Region Transcripts. Genomics Inform 2009. [DOI: 10.5808/gi.2009.7.4.181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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So MK, Gowrishankar G, Hasegawa S, Chung JK, Rao J. Imaging Target mRNA and siRNA-Mediated Gene Silencing In Vivo with Ribozyme-Based Reporters. Chembiochem 2008; 9:2682-91. [DOI: 10.1002/cbic.200800370] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Song MS, Jeong JS, Ban G, Lee JH, Won YS, Cho KS, Kim IH, Lee SW. Validation of tissue-specific promoter-driven tumor-targeting trans-splicing ribozyme system as a multifunctional cancer gene therapy device in vivo. Cancer Gene Ther 2008; 16:113-25. [PMID: 18758435 DOI: 10.1038/cgt.2008.64] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A trans-splicing ribozyme that can specifically reprogram human telomerase reverse transcriptase (hTERT) RNA was previously suggested as a useful tool for tumor-targeted gene therapy. In this study, we applied transcriptional targeting with the RNA replacement approach to target liver cancer cells by combining a liver-selective promoter with an hTERT-mediated cancer-specific ribozyme. To validate effects of this system in vivo, we constructed an adenovirus encoding for the hTERT-targeting trans-splicing ribozyme under the control of a liver-selective phosphoenolpyruvate carboxykinase promoter. We observed that intratumoral injection of this virus produced selective and efficient regression of tumors that had been subcutaneously inoculated with hTERT-positive liver cancer cells in mice. Importantly, the trans-splicing reaction worked equally well in a nude mouse model of hepatocarcinoma-derived peritoneal carcinomatosis, inducing the highly specific expression of a transgene, and moreover, the efficient regression of the hTERT-positive liver tumors with minimal liver toxicity when systemically delivered with the adenovirus. In addition to the observed hTERT-dependent therapeutic gene induction, significant reductions in the levels of hTERT RNA (approximately 75%) were also observed. In conclusion, this study demonstrates that a cancer-specific RNA replacement approach using trans-splicing ribozyme with a tissue-selective promoter represents a promising strategy for cancer treatment.
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Affiliation(s)
- M-S Song
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Suji-Gu, Yongin, Republic of Korea
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Song MS, Lee SW. In Vivo Target RNA Specificity of Trans-Splicing Phenomena by the Group I Intron. Genomics Inform 2008. [DOI: 10.5808/gi.2008.6.2.084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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35
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Antitumor Effects of Systemically Delivered Adenovirus Harboring Trans-Splicing Ribozyme in Intrahepatic Colon Cancer Mouse Model. Clin Cancer Res 2008; 14:281-90. [DOI: 10.1158/1078-0432.ccr-07-1524] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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36
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Hong SH, Jeong JS, Lee YJ, Jung HI, Cho KS, Kim CM, Kwon BS, Sullenger BA, Lee SW, Kim IH. In Vivo Reprogramming of hTERT by Trans-splicing Ribozyme to Target Tumor Cells. Mol Ther 2008; 16:74-80. [PMID: 17700543 DOI: 10.1038/sj.mt.6300282] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We have developed and validated a new tumor-targeting gene therapy strategy based upon the targeting and replacement of human telomerase reverse transcriptase (hTERT) RNA, using a trans-splicing ribozyme. By constructing novel adenoviral vectors harboring the hTERT-targeting trans-splicing ribozymes with the downstream reporter gene (Ad-Ribo-LacZ) or suicide gene (Ad-Ribo-HSVtk) driven by the cytomegalovirus (CMV) promoter, we demonstrated that this viral system selectively marks tumor cells expressing hTERT or sensitizes tumor cells to prodrug treatments. We confirmed that Ad-Ribo-LacZ successfully and selectively delivered a ribozyme that performed a highly specific trans-splicing reaction into hTERT-expressing cancer cells, both in vitro and in a peritoneal carcinomatosis nude mouse model. We also determined that the hTERT-specific expression of the suicide gene in the Ad-Ribo-HSVtk, and treatment with the corresponding prodrug, reduced tumor progression with almost the same efficacy as the strong constitutive CMV promoter-driven adenovirus, both in cancer cell lines and in nude mouse HT-29 xenografts. These observations provide the basis for a novel approach to cancer gene therapy, and demonstrate that trans-splicing ribozymes can be employed as targeting anti-cancer agents which recognize cancer-specific transcripts and reprogram them, thereby combating cancerous cells.
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Affiliation(s)
- Seung-Hee Hong
- Research Institute & Hospital, National Cancer Center, Goyang, South Korea
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Abstract
Asian countries, in particular China, Japan, and Korea, have been aggressively researching and developing gene medicines over the last 15 years or so. In China, an adenovirus expressing p53 was approved for commercial use in the year 2003, and has been on the actual market since then, becoming the world's first commercial gene-based drug. In Japan and Korea, many interesting scientific discoveries have been made, and industrially valuable technologies have been developed. It is particularly noteworthy to see that in these countries, gene therapy has been very keenly nurtured in relation with industrial and financial sectors. Despite remarkable progresses made in Asia, however, their activities have not been visibly noticed by many scientists in the US and European countries. This article briefly reviews key features of the past achievements and recent progresses made in three Asian countries.
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Affiliation(s)
- Sunyoung Kim
- Department of Biological Sciences, Seoul National University, Seoul, Korea.
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Hong SH, Jeong JS, Lee YJ, Jung HI, Kim KT, Kim YH, Lee YS, Lee SW, Bae CD, Park J, Kim IH. Molecular imaging of endogenous mRNA expression in a mouse tumor model by adenovirus harboringtrans-splicing ribozyme. FEBS Lett 2007; 581:5396-400. [DOI: 10.1016/j.febslet.2007.10.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 10/17/2007] [Accepted: 10/18/2007] [Indexed: 11/27/2022]
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Kim A, Ban G, Song MS, Bae CD, Park J, Lee SW. Selective Regression of Cells Expressing Mouse Cytoskeleton-Associated Protein 2 Transcript by Trans-Splicing Ribozyme. Oligonucleotides 2007; 17:95-103. [PMID: 17461766 DOI: 10.1089/oli.2007.0044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cytoskeleton-associated protein 2 (CKAP2) is known to be highly expressed in primary human cancers as well as most cancer cell lines. CKAP2 functions as microtubule stabilizer and probably as cell proliferation inducer, indicating that CKAP2 might be a potential anticancer target. In this study, we developed a specific ribozyme that can replace mouse CKAP2 (mCKAP2) RNA with new transcripts through trans-splicing reaction. This specific RNA replacement resulted in triggering of transgene activity selectively in mammalian cells that express the mCKAP2 RNA. Simultaneously, the ribozyme reduced the expression level of the target RNA in the cells. Noticeably, the ribozyme selectively induced activity of the suicide gene herpes simplex virus thymidine kinase in cells expressing the mCKAP2 RNA and thereby specifically retarded the survival of these cells with ganciclovir treatment. This mCKAP2-specific ribozyme will be useful for validation of the RNA replacement as cancer gene therapy approach in mouse model with syngeneic tumors.
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Affiliation(s)
- Areum Kim
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Seoul 140-714, Korea
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40
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Abstract
Ribozymes are RNA molecules capable of associating with other RNA molecules through base-pairing and catalyzing various reactions involving phosphate group transfer. Of particular interest to us is the well known ribozyme from Tetrahymena thermophila capable of catalyzing RNA splicing in eukaryotic systems, chiefly because of its potential use as a gene therapy agent. In this article we review the progress made towards visualizing the RNA splicing mediated by the Tetrahymena ribozyme in single living mammalian cells with the beta-lactamase reporter system and highlight the development made in imaging RNA splicing with the luciferase reporter system in living animals.
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Affiliation(s)
- Gayatri Gowrishankar
- Molecular Imaging Program at Stanford, Department of Radiology & Bio-X Program, Cancer Biology Program, Stanford University School of Medicine, 1201 Welch Road, Stanford, California 94305-5484, USA.
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Won YS, Lee SW. Targeted retardation of hepatocarcinoma cells by specific replacement of alpha-fetoprotein RNA. J Biotechnol 2007; 129:614-9. [PMID: 17360066 DOI: 10.1016/j.jbiotec.2007.02.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2006] [Revised: 01/16/2007] [Accepted: 02/07/2007] [Indexed: 10/23/2022]
Abstract
Although hepatocellular carcinoma (HCC) is one of the world-wide common malignancies, development of more specific and controlled therapeutic methods should be warranted. In this study, we describe a novel approach to HCC therapy that is based on trans-splicing ribozyme-mediated replacement of HCC-associated specific RNAs. We have developed a specific ribozyme that can target and replace human alpha-fetoprotein (AFP) RNA, which is highly expressed in HCC, with new transcript exerting therapeutic activity selectively in AFP-expressing liver cancer cells. The RNA replacement was employed via a high-fidelity trans-splicing reaction with the targeted residue in the AFP-expressing cells. Noticeably, the ribozyme could selectively deliver activity of suicide gene, herpes simplex virus thymidine kinase gene, into the liver cancer cells expressing the AFP RNA and thereby specifically and effectively retarded the survival of these cells with ganciclovir treatment. Simultaneously with the specific induction of therapeutic gene activity, the ribozyme reduced expression level of the targeted AFP RNA in the cells. These results suggest that the AFP RNA-targeting trans-splicing ribozyme could be a useful genetic agent for HCC-targeted efficient gene therapy.
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Affiliation(s)
- You-Sub Won
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, San8, Hannam-Dong, Yongsan-Gu, Seoul, Republic of Korea
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Jung HS, Lee SW. Ribozyme-mediated selective killing of cancer cells expressing carcinoembryonic antigen RNA by targeted trans-splicing. Biochem Biophys Res Commun 2006; 349:556-63. [PMID: 16945335 DOI: 10.1016/j.bbrc.2006.08.073] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 08/14/2006] [Indexed: 12/20/2022]
Abstract
Carcinoembryonic antigen (CEA) has been shown to be involved in a variety of neoplasia process, such as tumor cell adhesion, metastasis, blocking of cellular immune mechanisms, and anti-apoptosis function. Therefore, CEA has been a potential target for anti-cancer therapy. In this study, we developed a specific ribozyme that can target CEA RNA and then reprogram the RNA with new transcripts, resulting in triggering of transgene activity selectively in cancer cells that express the RNA. The ribozyme-mediated induction of the transgene expression was caused via a highly accurate and specific RNA replacement through trans-splicing reaction with the targeted residue in the CEA-expressing cells. Simultaneously with the specific RNA replacement, the ribozyme efficiently reduced expression level of the targeted CEA RNA in the cells. Importantly, the ribozyme could selectively deliver activity of suicide gene, herpes simplex virus thymidine kinase gene, into cancer cells expressing the CEA RNA and thereby specifically retarded the survival of these cells with ganciclovir treatment. These suggest that the CEA RNA-targeting trans-splicing ribozyme could be a powerful genetic agent for specific cancer gene therapy.
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Affiliation(s)
- Heung-Su Jung
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Seoul 140-714, Republic of Korea
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Song MS, Lee SW. Cancer-selective induction of cytotoxicity by tissue-specific expression of targetedtrans-splicing ribozyme. FEBS Lett 2006; 580:5033-43. [PMID: 16949075 DOI: 10.1016/j.febslet.2006.08.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Revised: 07/18/2006] [Accepted: 08/04/2006] [Indexed: 10/24/2022]
Abstract
For suicide gene therapy to be successfully applied for clinical settings, cancer-restricted expression of such suicide gene should be required. We previously showed that group I intron from Tetrahymena can induce new RNA that exerts anti-cancer activity through RNA replacement by trans-splicing reaction with high fidelity and specificity onto targeted human telomerase reverse transcriptase (hTERT) RNA in cancer cells, and hence the ribozyme can selectively retard growth of the cells in vivo as well as in vitro. However, the shortage of complete tumor-selectivity due to telomerase expression of highly proliferating normal cells can limit therapeutic applicability of the hTERT-targeting approach. In this study, to explore the possibility of improving specificity of cancer therapy, we have attempted to stimulate anticancer gene activity specifically in liver cancer cells by tissue-specific expression of the hTERT-targeting trans-splicing ribozyme using liver-specific promoters. Transient transfection experiments demonstrated that the expression of transgene such as luciferase gene was specifically and highly triggered from hTERT-expressing liver cancer cells transfected with the ribozyme. Moreover, liver-specific expression of the ribozyme with diphtheria toxin A or herpes simplex virus thymidine kinase gene as 3' exon could specifically and highly retard the growth of the hTERT-expressing liver cancer cells. In conclusion, we can greatly improve specificity of cancer cytotoxicity by combination of transcriptional targeting for tissue-specific transgene expression with RNA replacement for cancer-specific anticancer gene induction.
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Affiliation(s)
- Min-Sun Song
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, San8 Hannam-Dong, Yongsan-Gu, Seoul 140-714, Republic of Korea
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