Engineered exosome-mediated delivery of functionally active miR-26a and its enhanced suppression effect in HepG2 cells

International Journal of Nanomedicine Dovepress open access to scientific and medical research O r i g in a l R e s e a r c h International Journal of Nanomedicine downloaded from https://www.dovepress.com/ by 213.32.59.121 on 12-Jul-2018 For personal use only. Open Access Full Text Article Engineered exosome-mediated delivery of functionally active miR-26a and its enhanced suppression effect in HepG2 cells This article was published in the following Dove Press journal: International Journal of Nanomedicine Gaofeng Liang 1,2,* Shu Kan 2,* Yanliang Zhu 3 Shuying Feng 1 Wenpo Feng 1 Shegan Gao 1,4 Medical College, Henan University of Science and Technology, Luoyang, China; 2Department of Biomedical Engineering, University of California Berkeley, California, CA, USA; 3State Key laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 4Henan Key Laboratory of Cancer Epigenetics, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, China 1 *These authors contributed equally to this work Introduction Correspondence: Shegan Gao Medical College, Henan Key Laboratory of Cancer Epigenetics, The First Affiliated Hospital of Henan University of Science and Technology, 263 Kaiyuan Ave, Luoyang 471003, China Email Gaofeng Liang Medical College, Henan University of Science and Technology, Luoyang 471003, Henan, China Email A major challenge in gene therapy is the development of nontoxic, molecular transport vehicles that efficiently deliver functional copies of a therapeutic gene to target cells. While viral vectors are frequently used for this purpose, their application to treat human cancers is limited by an inherent toxicity, potential infectivity, and immunogenicity.1 Alternative nonviral vector platforms have also been developed for gene targeting and delivery, examples of which include synthetic polymers, micelles, and nanoparticles.2 Although promising in animal models of human disease, these vehicles are limited by the same problems encountered by viral-derived vehicles.3 These limitations could be overcome by using host-derived, “living” gene delivery vehicles, examples of which may include engineered exosomes,4 blood platelets,5–7 and red blood cells.8 Exosomes are natural lipid membrane-enclosed vesicles that have a broad range of diameters (30–150 nm) and are synthesized and released by a variety of cells types.9 The natural internal cargo of exosomes includes specific mRNAs, miRNAs, and proteins that can be transported to remote target cells in many cases. This targeting is achieved by specific interactions of 585 submit your manuscript | www.dovepress.com International Journal of Nanomedicine 2018:13 585–599 Dovepress © 2018 Liang et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). http://dx.doi.org/10.2147/IJN.S154458 Powered by TCPDF (www.tcpdf.org) Introduction: Exosomes are closed-membrane nanovesicles that are secreted by a variety of cells and exist in most body fluids. Recent studies have demonstrated the potential of exosomes as natural vehicles that target delivery of functional small RNA and chemotherapeutics to diseased cells. Methods: In this study, we introduce a new approach for the targeted delivery of exosomes loaded with functional miR-26a to scavenger receptor class B type 1-expressing liver cancer cells. The tumor cell-targeting function of these engineered exosomes was introduced by expressing in 293T cell hosts, the gene fusion between the transmembrane protein of CD63 and a sequence from Apo-A1. The exosomes harvested from these 293T cells were loaded with miR-26a via electroporation. Results: The engineered exosomes were shown to bind selectively to HepG2 cells via the scavenger receptor class B type 1–Apo-A1 complex and then internalized by receptor-mediated endocytosis. The release of miR-26a in exosome-treated HepG2 cells upregulated miR-26a expression and decreased the rates of cell migration and proliferation. We also presented evidence that suggest cell growth was inhibited by miR-26a-mediated decreases in the amounts of key proteins that regulate the cell cycle. Conclusion: Our gene delivery strategy can be adapted to treat a broad spectrum of cancers by expressing proteins on the surface of miRNA-loaded exosomes that recognize specific biomarkers on the tumor cell. Keywords: exosome, gene delivery, miR-26a, HepG2 cells Dovepress International Journal of Nanomedicine downloaded from https://www.dovepress.com/ by 213.32.59.121 on 12-Jul-2018 For personal use only. Liang et al proteins on the exosomal membrane with receptor molecules on the target cell.10 We and others have also shown that the molecular cargo transported and delivered by exosomes to target cells can influence pathological and physiological processes in the target cell or tissue, including immune responses, blood coagulation, tumor growth, and tissue repair.11–15 Furthermore, the presence of specific genetic information within exosomes derived from tumor cells offers opportunities to develop simple liquid biopsy-based approaches for cancer detection or to monitor the effectiveness of a cancer treatment.16,17 Exosomes exhibit unique features that could be exploited to enhance their performance as personalized vehicles for targeted delivery of therapeutics to diseased cells and tissue. First, since they are produced in a patient, they are recognized as “self”, which increases their stability in serum. Moreover, their longer circulation compared with artificial nanovehicles will result in a significant increase in the chance of this molecule encountering with target cells, even deep-seated tumor cells.5 Also significant in this regard are studies that show exosomes traverse intact biological barriers, including the blood–brain barrier (BBB), and have an ability to deliver functional RNA and small molecule drugs to target cells.4,18–20 The intrinsic cell-targeting property of exosomes can be further enhanced by using genetic engineering techniques to introduce specific proteins to their surface, including ligands for receptors (Apo-A1) or antibodies directed against tumor biomarkers.21,22 Alvarez-Erviti et al, for example, engineered exosomes produced by dendritic cells to express the neuron-specific rabies viral glycoprotein peptide, which binds to the acetylcholine receptor expressed on neuronal (...truncated)