Objective
Surface Plasmon Resonance (SPR) is
a widely used label-free detection technique for studying binding behavior of
biomolecules. Since its commercialization in 1990’s, SPR has made vast advances
in terms of both development of the technology and its applications. It has
become a central tool in biomedical research, biosensor development and drug
discovery. One of the most significant
developments in recent years is SPR Microscopy (SPRM), a powerful technique
that integrates SPR and optical microscopy technology. SPRM provides the ability to simultaneously
visualize cellular structures and measure molecular interactions of membrane
proteins label-free,
in vitro and
real time. With this technique, the simultaneous measurement of phenotypical
changes of the cell via bright field and binding affinity and kinetics via SPR
can be done.
In this study, three types of
cells, Chinese hamster ovary (CHO) cells, SH-EP1 human epithelial cells and
Barrett’s esophagus-derived CP-D (CP-18821) cells were used to measure the
binding kinetics of glycoproteins. Glycoproteins are glycosylated membrane
proteins that play an inte- gral role in the cell-cell and cell-matrix recognition
events. Wheat-germ agglutinin (WGA) (36k Da) is a lectin protein that can
recognize sugar residues on glycoproteins. SPRm was used to measure the binding
kinetics between WGA and whole cells label-free and in real-time. When WGA is
exposed to the cells an increase in SPR signal is observed indicating that the
WGA lectin proteins are binding to the sugar residues of the cell membrane
glycoproteins.
G-protein coupled receptors (GPCR)
are membrane proteins that play key roles in sensorial, hormonal, metabolic,
immunological and neurotransmission processes.
Despite its importance, quantifying the binding of drug candidates with
GPCRs are difficult to do with traditional SPR detection techniques. In this study, we will present SPR Microscopy
data of a few small molecule drugs binding to GPCRs on various cell lines.
