Isolation and 111in–oxine labeling of murine NK cells for assessment of cell trafficking in orthotopic lung tumor model

Malviya, G. , Nayak, T., Gerdes, C., Dierckx, R. A.J.O., Signore, A. and de Vries, E. F.J. (2016) Isolation and 111in–oxine labeling of murine NK cells for assessment of cell trafficking in orthotopic lung tumor model. Molecular Pharmaceutics, 13(4), pp. 1329-1338. (doi: 10.1021/acs.molpharmaceut.5b00947) (PMID:26962716)

Abstract

A noninvasive in vivo imaging method for NK cell trafficking is essential to gain further understanding of the pathogenesis of NK cell mediated immune response to the novel cancer treatment strategies, and to discover the homing sites and physiological distribution of NK cells. Although human NK cells can be labeled for in vivo imaging, little is known about the murine NK cell labeling and its application in animal models. This study describes the isolation and ex vivo radiolabeling of murine NK cells for the evaluation of cell trafficking in an orthotopic model of human lung cancer in mice. Scid-Tg(FCGR3A)Blt transgenic SCID mice were used to isolate NK cells from mouse splenocytes using the CD49b (DX5) MicroBeads positive selection method. The purity and viability of the isolated NK cells were confirmed by FACS analysis. Different labeling buffers and incubation times were evaluated to optimize 111In–oxine labeling conditions. Functionality of the radiolabeled NK cell was assessed by 51Cr-release assay. We evaluated physiological distribution of 111In–oxine labeled murine NK cells in normal SCID mice and biodistribution in irradiated and nonirradiated SCID mice with orthotopic A549 human lung tumor lesions. Imaging findings were confirmed by histology. Results showed that incubation with 0.011 MBq of 111In–oxine per million murine NK cells in PBS (pH 7.4) for 20 min is the best condition that provides optimum labeling efficiency without affecting cell viability and functionality. Physiological distribution in normal SCID mice demonstrated NK cells homing mainly in the spleen, while 111In released from NK cells was excreted via kidneys into urine. Biodistribution studies demonstrated a higher lung uptake in orthotopic lung tumor-bearing mice than control mice. In irradiated mice, lung tumor uptake of radiolabeled murine NK cells decreased between 24 h and 72 h postinjection (p.i.), which was accompanied by tumor regression, while in nonirradiated mice, radiolabeled NK cells were retained in the lung tumor lesions up to 72 h p.i. without tumor regression. In tumor-bearing mice that were only irradiated but did not receive radiolabeled murine NK cells, a high tumor burden was observed at 72 h p.i., which indicates that irradiation in combination with murine NK cell allocation, but not irradiation alone, induced a remarkable antitumor effect in the orthotopic A549 lung tumor bearing mouse model. In conclusion, we describe a method to evaluate murine NK cell trafficking and biodistribution, which can be used to determine potential effects of immune-mediated therapeutic agents on NK cell biodistribution.

• Item Type: Articles
• Additional Information: The research work performed in the manuscript was funded by the Roche Postdoctoral Fellowship Program, Pharma Research and Early Development, Roche Innovation Center, Basel, Switzerland. The contribution of A.S. was partially supported by AIRC Research Grant IG-14151.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Malviya, Dr Gaurav
• Authors: Malviya, G., Nayak, T., Gerdes, C., Dierckx, R. A.J.O., Signore, A., and de Vries, E. F.J.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences
• Journal Name: Molecular Pharmaceutics
• Publisher: American Chemical Society
• ISSN: 1543-8384
• ISSN (Online): 1543-8392
• Published Online: 10 March 2016
• Copyright Holders: Copyright © 2016 American Chemical Society
• First Published: First published in Molecular Pharmaceutics 13(4):1329-1338
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher