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A cCPE‐based xenon biosensor for magnetic resonance imaging of claudin‐expressing cells
Author(s) -
Piontek Anna,
Witte Christopher,
May Rose Honor,
Eichner Miriam,
Protze Jonas,
Krause Gerd,
Piontek Jörg,
Schröder Leif
Publication year - 2017
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/nyas.13363
Subject(s) - claudin , biosensor , flow cytometry , chemistry , hek 293 cells , fluorescence , magnetic resonance imaging , enterotoxin , biophysics , microbiology and biotechnology , tight junction , biochemistry , biology , receptor , gene , medicine , physics , quantum mechanics , radiology , escherichia coli
The majority of malignant tumors originate from epithelial cells, and many of them are characterized by an overexpression of claudins (Cldns) and their mislocalization out of tight junctions. We utilized the C‐terminal claudin‐binding domain of Clostridium perfringens enterotoxin (cCPE), with its high affinity to specific members of the claudin family, as the targeting unit for a claudin‐sensitive cancer biosensor. To overcome the poor sensitivity of conventional relaxivity‐based magnetic resonance imaging (MRI) contrast agents, we utilized the superior sensitivity of xenon Hyper‐CEST biosensors. We labeled cCPE for both xenon MRI and fluorescence detection. As one readout module, we employed a cryptophane (CrA) monoacid and, as the second, a fluorescein molecule. Both were conjugated separately to a biotin molecule via a polyethyleneglycol chemical spacer and later via avidin linked to GST–cCPE. Nontransfected HEK293 cells and HEK293 cells stably expressing Cldn4–FLAG were incubated with the cCPE‐based biosensor. Fluorescence‐based flow cytometry and xenon MRI demonstrated binding of the biosensor specifically to Cldn4‐expressing cells. This study provides proof of concept for the use of cCPE as a carrier for diagnostic contrast agents, a novel approach for potential detection of Cldn3/‐4–overexpressing tumors for noninvasive early cancer detection.