Affinity peptide for targeted detection of dysplasia in Barrett's esophagus.
OBJECTIVE
Dysplasia is a premalignant condition in Barrett's esophagus that is difficult to detect on endoscopy because of its flat architecture and patchy distribution. Peptides are promising for use as novel molecular probes that identify cell surface targets unique to disease and can be fluorescence-labeled for detection. We aim to select and validate an affinity peptide that binds to esophageal dysplasia for future clinical studies.


METHODS
Peptide selection was performed using phage display by removing nonspecific binders using Q-hTERT (intestinal metaplasia) cells and achieving specific binding against OE33 (esophageal adenocarcinoma) cells. Selective binding was confirmed on bound phage counts, enzyme-linked immunosorbent assay (ELISA), flow cytometry, competitive inhibition, and fluorescence microscopy. On stereomicroscopy, specific peptide binding to dysplasia on endoscopically resected specimens was assessed by rigorous registration of fluorescence intensity to histology in 1-mm intervals.


RESULTS
The peptide sequence SNFYMPL was selected and showed preferential binding to target cells. Reduced binding was observed on competition with unlabeled peptide in a dose-dependent manner, an affinity of K(d) = 164 nmol/L was measured, and peptide binding to the surface of OE33 cells was validated on fluorescence microscopy. On esophageal specimens (n = 12), the fluorescence intensity (mean ± SEM) in 1-mm intervals classified histologically as squamous (n = 145), intestinal metaplasia (n = 83), dysplasia (n = 61), and gastric mucosa (n = 69) was 46.5 ± 1.6, 62.3 ± 5.8, 100.0 ± 9.0, and 42.4 ± 3.0 arb units, respectively.


CONCLUSIONS
The peptide sequence SNFYMPL binds specifically to dysplasia in Barrett's esophagus and can be fluorescence labeled to target premalignant mucosa on imaging.
Li
Meng
M
Division of Gastroenterology, Department of Medicine, State Key Laboratory of Cancer Biology, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China.
Anastassiades
Constantinos P
CP
Joshi
Bishnu
B
Komarck
Chris M
CM
Piraka
Cyrus
C
Elmunzer
Badih J
BJ
Turgeon
Danielle K
DK
Johnson
Timothy D
TD
Appelman
Henry
H
Beer
David G
DG
Wang
Thomas D
TD
D000345:Affinity Labels; D001471:Barrett Esophagus / Q000175:diagnosis* / Q000378:metabolism; D001665:Binding Sites; D002352:Carrier Proteins; D002478:Cells, Cultured; D003937:Diagnosis, Differential; D018450:Disease Progression; D042241:Early Diagnosis; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology*; D008856:Microscopy, Fluorescence
D000345:Affinity Labels; D002352:Carrier Proteins