Liya Zhu1, Senthilkumar Kalimuthu1, Ji Min Oh1, Prakash Gangadaran1, Se Hwan Baek1, Shin Young Jeong1, Sang-Woo Lee1, Jaetae Lee1, Byeong-Cheol Ahn2. 1. Department of Nuclear Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu 41944, South Korea. 2. Department of Nuclear Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu 41944, South Korea. Electronic address: abc2000@knu.ac.kr.
Abstract
PURPOSE: Natural killer (NK) cells are the key subset of innate-immunity lymphocytes; they possess antitumor activities and are used for cancer immunotherapy. In a previous study, extracellular vehicles (EVs) from NK-92MI cells were isolated and exploited for their ability to kill human cancer cells in vitro and in vivo (multiple injection methods). Here, the potential of NK-cell-derived EVs (NK-EVs) for immunotherapy was improved by priming with interleukin (IL)-15. METHODS: NK-EVs were isolated from the culture medium without or with IL-15 (NK-EVsIL-15) by ultracentrifugation and were purified via density gradient ultracentrifugation. In addition, NK-EVs and NK-EVsIL-15 were characterized by transmission electron microscopy, nanoparticle-tracking analysis, and western blotting. Flow cytometry, bioluminescence imaging, and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were performed for apoptosis, protein expression, cell proliferation, and cytotoxicity analyses. Furthermore, xenograft tumor-bearing mice were injected with PBS, NK-EVs, or NK-EVsIL-15 intravenously five times. Tumor growth was monitored using calipers and bioluminescence imaging. Toxicity of the nanoparticles was evaluated by measuring the body weight of the mice. RESULTS: NK-EVsIL-15 showed significantly higher cytolytic activity toward human cancer cell lines (glioblastoma, breast cancer, and thyroid cancer) and simultaneously increased the expression of molecules associated with NK-cell cytotoxicity. When compared with NK-EVs, NK-EVsIL-15 significantly inhibited the growth of glioblastoma xenograft cells in mice. In addition, both NK-EVs and NK-EVsIL-15 were not significantly toxic to either normal cells or mice. CONCLUSION: IL-15 may improve the immunotherapeutic effects of NK-EVs, thus improving the applications of NK-EVs in the future.
PURPOSE: Natural killer (NK) cells are the key subset of innate-immunity lymphocytes; they possess antitumor activities and are used for cancer immunotherapy. In a previous study, extracellular vehicles (EVs) from NK-92MI cells were isolated and exploited for their ability to kill humancancer cells in vitro and in vivo (multiple injection methods). Here, the potential of NK-cell-derived EVs (NK-EVs) for immunotherapy was improved by priming with interleukin (IL)-15. METHODS:NK-EVs were isolated from the culture medium without or with IL-15 (NK-EVsIL-15) by ultracentrifugation and were purified via density gradient ultracentrifugation. In addition, NK-EVs and NK-EVsIL-15 were characterized by transmission electron microscopy, nanoparticle-tracking analysis, and western blotting. Flow cytometry, bioluminescence imaging, and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were performed for apoptosis, protein expression, cell proliferation, and cytotoxicity analyses. Furthermore, xenograft tumor-bearing mice were injected with PBS, NK-EVs, or NK-EVsIL-15 intravenously five times. Tumor growth was monitored using calipers and bioluminescence imaging. Toxicity of the nanoparticles was evaluated by measuring the body weight of the mice. RESULTS:NK-EVsIL-15 showed significantly higher cytolytic activity toward humancancer cell lines (glioblastoma, breast cancer, and thyroid cancer) and simultaneously increased the expression of molecules associated with NK-cell cytotoxicity. When compared with NK-EVs, NK-EVsIL-15 significantly inhibited the growth of glioblastoma xenograft cells in mice. In addition, both NK-EVs and NK-EVsIL-15 were not significantly toxic to either normal cells or mice. CONCLUSION:IL-15 may improve the immunotherapeutic effects of NK-EVs, thus improving the applications of NK-EVs in the future.
Authors: Sierra Walker; Sara Busatto; Anthony Pham; Ming Tian; Annie Suh; Kelsey Carson; Astrid Quintero; Maria Lafrence; Hanna Malik; Moises X Santana; Joy Wolfram Journal: Theranostics Date: 2019-10-17 Impact factor: 11.556