Generation of PRL-3- and PRL-1-specific monoclonal antibodies as potential diagnostic markers for cancer metastases.
OBJECTIVE
The PRL-3 mRNA is consistently elevated in metastatic samples derived from colorectal cancers. We sought to generate a specific PRL-3 monoclonal antibody (mAb) that might serve as a potential diagnostic marker for colorectal cancer metastasis.


METHODS
PRL-3 is one of three members (PRL-1, PRL-2, and PRL-3) in a unique protein-tyrosine phosphatase family. Because the three PRLs are 76% to 87% identical in their amino acid sequences, it poses a great challenge to obtain mAbs that are specific for respective phosphatase of regenerating liver (PRL) but not for the other two in the family. We screened over 1,400 hybridoma clones to generate mAbs specific to each PRL member.


RESULTS
We obtained two hybridoma clones specifically against PRL-3 and another two clones specifically against PRL-1. These antibodies had been evaluated by several critical tests to show their own specificities and applications. Most importantly, the PRL-3 mAbs were assessed on 282 human colorectal tissue samples (121 normal, 17 adenomas, and 144 adenocarcinomas). PRL-3 protein was detected in 11% of adenocarcinoma samples. The PRL-3- and PRL-1-specific mAbs were further examined on 204 human multiple cancer tissues. The differential expressions of PRL-3 and PRL-1 confirmed the mAbs' specificity.


CONCLUSIONS
Using several approaches, we show that PRL-3- or PRL-1-specific mAbs react only to their respective antigen. The expression of PRL-3 in >10% of primary colorectal cancer samples indicates that PRL-3 may prime the metastatic process. These mAbs will be useful as markers in clinical diagnosis for assessing tumor aggressiveness.
Li
Jie
J
Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673.
Guo
Ke
K
Koh
Vicki Wei Chyi
VW
Tang
Jing Ping
JP
Gan
Bin Qi
BQ
Shi
Hong
H
Li
Hui Xiang
HX
Zeng
Qi
Q
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000556:secondary; D000236:Adenoma / Q000175:diagnosis*; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000276:immunology*; D015153:Blotting, Western; D018797:Cell Cycle Proteins; D003106:Colon / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D006825:Hybridomas; D017874:Immediate-Early Proteins / Q000276:immunology*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D011379:Prognosis; D017027:Protein Tyrosine Phosphatases / Q000276:immunology*; D012007:Rectum / Q000378:metabolism; D012680:Sensitivity and Specificity; D017386:Sequence Homology, Amino Acid
D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D017874:Immediate-Early Proteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; C490198:PTP4A1 protein, human; C484730:PTP4A3 protein, human; D017027:Protein Tyrosine Phosphatases