MRI of prostate stem cell antigen expression in prostate tumors.
BACKGROUND
The prostate stem cell antigen (PSCA) is broadly overexpressed on the surface of prostate cancer cells.


METHODS
Anti-human PSCA monoclonal antibody (mAb 7F5) was bound to Fe(3)O(4)/Au (GoldMag) nanoparticles to serve as a PSCA-specific molecular MRI probe (mAb 7F5@GoldMag) for in vivo detection of prostate cancer cells. First, the efficacy of the antibody immobilization for the binding was assessed. Next, PC-3 (human prostate cancer cell line with PSCA overexpression) tumor-bearing mice were injected with mAb 7F5@GoldMag for MRI measurements while using mouse anti-human IgG bound to the particles (IgG@GoldMag) to serve as a nonspecific control. MRI examinations were conducted before and after injection of these probes at 6, 12 and 24 h; T2-weighted signal intensity within the tumors was measured.


RESULTS
Targeted binding of the mAb 7F5@GoldMag probe to PC-3 tumors was verified with optical images and MRI; selective binding was not observed for the nonspecific IgG@GoldMag probe.


CONCLUSIONS
MRI measurements suggest the promising efficacy of this new approach for targeted molecular imaging of prostate tumors.
Department of Radiology, Fourth Military Medical University, Xian 710032, China.
Jing
J
Ren
Zhuoli
Z
Zhang
Fang
F
Wang
Yong
Y
Yang
Ying
Y
Liu
Guangquan
G
Wei
Angang
A
Yang
Rui
R
Zhang
Yi
Y
Huan
Yali
Y
Cui
Andrew C
AC
Larson
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000008:administration & dosage / Q000737:chemistry; D055910:Antibodies, Immobilized / Q000008:administration & dosage / Q000737:chemistry; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000276:immunology; D058851:GPI-Linked Proteins / Q000737:chemistry / Q000276:immunology; D006046:Gold / Q000008:administration & dosage / Q000737:chemistry; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D053768:Metal Nanoparticles / Q000008:administration & dosage / Q000737:chemistry; D051379:Mice; D057054:Molecular Imaging; D058990:Molecular Targeted Therapy; D009363:Neoplasm Proteins / Q000737:chemistry / Q000276:immunology; D014411:Neoplastic Stem Cells / Q000000981:diagnostic imaging / Q000276:immunology; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000276:immunology; D011859:Radiography
D000888:Antibodies, Anti-Idiotypic; D055910:Antibodies, Immobilized; D000951:Antigens, Neoplasm; D058851:GPI-Linked Proteins; D009363:Neoplasm Proteins; C110843:PSCA protein, human; C048844:anti-IgG; D006046:Gold