[Expression of prostate stem cell antigen (PSCA) and selection of its specific binding peptide].
Prostate stem cell antigen (PSCA), a homologue of the Ly-6/Thy-1 family of cell surface antigen, is expressed by a majority of human prostate cancers and is a promising target for prostate cancer immunotherapy. To obtain the specific peptide binding with PSCA for targeted immunotherapy, PSCA gene was obtained by RT-PCR from human prostate cancer cell line DU145 and the transcated PSCA (tPSCA) gene was cloned into vector pQE30 for soluble expression in E. coli. The identity of recombinant tPSCA was confirmed through ELISA and western blot by use of anti-PSCA monoclonal antibody. Then the 12-peptide phage display library was screened with the purified tPSCA protein for its specific binding peptide through 3 rounds panning. For identifying the peptide's specificity, the peptide was coupled with EGFP (enhanced green fluorecent protein) by recombinant DNA technology and the recombinant coupled protein was termed 11-EGFP. The binding specificity with tPSCA of 11-EGFP was further confirmed by ELISA and competitive inhibition experiment. Flow cytometry demonstrated its binding specificity with cell line DU145. In conclusion, a 12-amino-acid peptide which could bind with PSCA specifically was found and it may be a potential tool for targeted immunotherapy of prostate carcinoma.
Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
Li-Hua
LH
Hou
Yong
Y
Du
Xiao-Peng
XP
Zhang
Xiao-Ping
XP
An
Wei
W
Chen
D000911:Antibodies, Monoclonal / Q000276:immunology; D000951:Antigens, Neoplasm; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005434:Flow Cytometry; D058851:GPI-Linked Proteins; D006801:Humans; D007167:Immunotherapy; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000276:immunology; D009363:Neoplasm Proteins / Q000235:genetics* / Q000276:immunology; D019151:Peptide Library; D010455:Peptides / Q000276:immunology*; D011471:Prostatic Neoplasms / Q000628:therapy
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C110843:PSCA protein, human; D019151:Peptide Library; D010455:Peptides