title: In vivo imaging of tumour xenografts with an antibody targeting the potassium channel Kv10.1.
abstract: The Kv10.1 (Eag1) voltage-gated potassium channel represents a promising molecular target for novel cancer therapies or diagnostic purposes. Physiologically, it is only expressed in the brain, but it was found overexpressed in more than 70 % of tumours of diverse origin. Furthermore, as a plasma membrane protein, it is easily accessible to extracellular interventions. In this study we analysed the feasibility of the anti-Kv10.1 monoclonal antibody mAb62 to target tumour cells in vitro and in vivo and to deliver therapeutics to the tumour. Using time-domain near infrared fluorescence (NIRF) imaging in a subcutaneous MDA-MB-435S tumour model in nude mice, we showed that mAb62-Cy5.5 specifically accumulates at the tumour for at least 1 week in vivo with a maximum intensity at 48 h. Blocking experiments with an excess of unlabelled mAb62 and application of the free Cy5.5 fluorophore demonstrate specific binding to the tumour. Ex vivo NIRF imaging of whole tumours as well as NIRF imaging and microscopy of tumour slices confirmed the accumulation of the mAb62-Cy5.5 in tumours but not in brain tissue. Moreover, mAb62 was conjugated to the prodrug-activating enzyme β-D-galactosidase (β-gal; mAb62-β-gal). The β-gal activity of the mAb62-β-gal conjugate was analysed in vitro on Kv10.1-expressing MDA-MB-435S cells in comparison to control AsPC-1 cells. We show that the mAb62-β-gal conjugate possesses high β-gal activity when bound to Kv10.1-expressing MDA-MB-435S cells. Moreover, using the β-gal activatable NIRF probe DDAOG, we detected mAb62-β-gal activity in vivo over the tumour area. In summary, we could show that the anti-Kv10.1 antibody is a promising tool for the development of novel concepts of targeted cancer therapy.
authors.affiliation: Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany.|Institute of Interventional and Diagnostic Radiology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.|Department of Haematology and Medical Oncology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
authors.forename: Joanna
authors.initials: J
authors.lastname: Napp
authors.affiliation: AG Oncophysiology, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Pardo
authors.affiliation: AG Oncophysiology, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Hartung
authors.affiliation: Institute of Organic and Biomolecular Chemistry, University Göttingen, Tammannstr. 2, 37077, Göttingen, Germany.
authors.forename: Lutz F
authors.initials: LF
authors.lastname: Tietze
authors.affiliation: Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany.
authors.forename: Walter
authors.initials: W
authors.lastname: Stühmer
authors.affiliation: Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany. falves@gwdg.de.|Institute of Interventional and Diagnostic Radiology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany. falves@gwdg.de.|Department of Haematology and Medical Oncology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany. falves@gwdg.de.
authors.forename: Frauke
authors.initials: F
authors.lastname: Alves
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D002232:Carbocyanines / Q000378:metabolism; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic; D051638:Ether-A-Go-Go Potassium Channels / Q000276:immunology* / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D061848:Optical Imaging / Q000379:methods*
chemical_list: D000911:Antibodies, Monoclonal; C098793:CY5.5 cyanine dye; D002232:Carbocyanines; D051638:Ether-A-Go-Go Potassium Channels; C496884:KCNH1 protein, human
keywords: Antibody targeting Kv10.1; Ion channel Kv10.1; Non-invasive near infrared fluorescence imaging; Novel therapeutic concepts; Oncology; Preclinical assessment of enzymatic activity