A new TAG-72 cancer marker peptide identified by phage display.
Radiolabeled peptides as markers of cancer targets have demonstrated their value in diagnostic imaging and radiotherapy. The 16 mer f88-4/Cys6 phage display library was applied to affinity purified TAG-72 and three consensus peptides were identified: VHHSCTKLTHCCQNWH (A2-13), GGVSCMQTSPVCENNL (A2-6) and TKRDCSAQNYGCQKAI (A2-11). The A2-13 and A2-6 phages showed the highest percent binding to LS-174T cells by flow cytometry and were 3-fold higher than a control phage, while fluorescence microscopy showed that both A2-6 and A2-13 phages bound to the LS-174T cell membrane. However, only the A2-6 phage demonstrated specificity by low binding to the TAG-72 negative cell HT-29. Furthermore, the synthesized free A2-6 peptide demonstrated specific binding to LS-174T cells by flow cytometry and by immunohistochemical staining of xenograft tumor compared to normal colon. These data indicate that the A2-6 peptide is specific for the TAG-72 cancer target.
Chen
Ling
L
Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
Wang
Yi
Y
Liu
Xinrong
X
Dou
Shuping
S
Liu
Guozheng
G
Hnatowich
Donald J
DJ
Rusckowski
Mary
M
D000230:Adenocarcinoma; D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm / Q000032:analysis* / Q000235:genetics; D001435:Bacteriophages / Q000235:genetics; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms; D016384:Consensus Sequence; D017931:DNA Primers; D005434:Flow Cytometry; D006023:Glycoproteins / Q000032:analysis* / Q000235:genetics; D019073:HT29 Cells; D006801:Humans; D010446:Peptide Fragments / Q000737:chemistry; D019151:Peptide Library
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D017931:DNA Primers; D006023:Glycoproteins; D010446:Peptide Fragments; D019151:Peptide Library; C047052:tumor-associated antigen 72