L6 monoclonal antibody binds prostate cancer.
BACKGROUND
Radioimmunotherapy (RIT) is a promising new modality for targeted, systemic delivery of radionuclides specifically to sites of androgen-independent metastatic prostate cancer. To be effective, RIT requires an antibody with specificity for malignant cells and appropriate pharmacokinetics in the body.


METHODS
Specific binding of the L6 monoclonal antibody to prostate cancer cell lines or cell lysates was determined by enzyme-linked immunoabsorbent assay (ELISA), solid-phase radioimmunoassay, and immunofluorescent staining. Biodistribution, tumor uptake, and whole body and blood clearances of 125I-L6 were determined in nude mice bearing human prostate cancer xenografts.


RESULTS
The L6 monoclonal antibody showed strong binding to the lysates of PC3 and DU145 prostate cancer cell lines, and 66% binding to live PC3 cells. The L6 antibody specifically targeted prostate cancer in PC3 and DU145-tumored nude mice, where approximately 10% of the injected dose of 125I-L6 bound to prostate cancer. Low-normal organ uptake was found, and the blood clearances were similar in each group of tumored mice.


CONCLUSIONS
The L6 monoclonal antibody targets human prostate cancer xenografts in nude mice and has low-normal organ uptake. Therefore, further study of the radiolabeled L6 monoclonal antibody for RIT of prostate cancer is warranted.
O'Donnell
R T
RT
Department of Internal Medicine, University of California Davis Medical Center, Sacramento, USA. rtodonnell@ucdavis.edu
DeNardo
S J
SJ
Shi
X B
XB
Mirick
G R
GR
DeNardo
G L
GL
Kroger
L A
LA
Meyers
F J
FJ
D000818:Animals; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics; D000951:Antigens, Neoplasm / Q000276:immunology; D006801:Humans; D008297:Male; D051379:Mice; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D016499:Radioimmunotherapy; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm