Dual-Color Bioluminescent Sensor Proteins for Therapeutic Drug Monitoring of Antitumor Antibodies

Abstract

Monitoring the levels of therapeutic antibodies in individual patients would allow patient-specific dose optimization, with the potential for major therapeutic and financial benefits. Our group recently developed a new platform of bioluminescent sensor proteins (LUMABS; LUMinescent AntiBody Sensor) that allow antibody detection directly in blood plasma. In this study, we targeted four clinically important therapeutic antibodies, the Her2-receptor targeting trastuzumab, the anti-CD20 antibodies rituximab and obinutuzumab, and the EGFR-blocking cetuximab. A strong correlation was found between the affinity of the antibody binding peptide and sensor performance. LUMABS sensors with physiologically relevant affinities and decent sensor responses were obtained for trastuzumab and cetuximab using mimotope and meditope peptides, respectively, with affinities in the 10–7 M range. The lower affinity of the CD20-derived cyclic peptide employed in the anti-CD20 LUMABS sensor (Kd = 10–5 M), translated in a LUMABS sensor with a strongly attenuated sensor response. The trastuzumab and cetuximab sensors were further characterized with respect to binding kinetics and their performance in undiluted blood plasma. For both antibodies, LUMABS-based detection directly in plasma compared well to the analytical performance of commercial ELISA kits. Besides identifying important design parameters for the development of new LUMABS sensors, this work demonstrates the potential of the LUMABS platform for point-of-care detection of therapeutic antibodies.

Recent Progress in Optical Sensors for Biomedical Diagnostics

“…It has been used to develop microfluidic paper-based assays for simultaneous nanomolar antibody detection in whole blood (Figure 10e) [202] using a novel platform called LUMinescent AntiBody Sensor (LUMABS) [203]. LUMABS with furimazine substrates compares well against ELISA [204] and is compatible with several different antibodies [205]. Furimazine systems have also been employed for intracellular ATP sensing [206], voltage indication in live cells [207] as well as metal ion detection and bioimaging [207][208][209].…”

Recent progress in the molecular imaging of therapeutic monoclonal antibodies

“…Bioluminescence does not require external excitation, avoiding background signals and light scattering during detection, making detection in complex matrices relatively straightforward. Merkx’s group [ 55 ] developed a bioluminescent platform (LUMABS) that allows mAb detection directly in blood plasma. Binding of an antibody to the epitope results in a great decrease in the bioluminescence resonance energy transfer (BRET) efficiency which can be detected directly in blood plasma even at low pM concentrations of antibody.…”

Ratiometric BRET Measurements of ATP with a Genetically-Encoded Luminescent Sensor

“…For example, bioluminescent reporters have been extensively used with rodent cancer models to measure signaling, tumor volume, and immune cell infiltration in vivo [6,7]. Additionally, a number of luminescent probes have been developed for metals and ions [8,9,10,11,12], second messengers [13,14], enzyme activity [15,16,17], protein-protein interactions [18,19,20,21], and reactive species [22,23,24,25], but these are predominantly used for in vitro assays, cultured cell models, or instrument development. One challenge in the development of genetically-encoded luciferase reporters is that the rapid decay of luminescence intensity over time poses a substantial problem for stable signal measurement.…”