Evaluation of CRMP-2L, a novel CRMP-2 isoform, as a tumor biomarker of colorectal cancer

• Main Authors: Shih Yu Lin, 林詩語
• Other Authors: J. Y. Yu
• Format: Others
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/03324699024414199984

碩士 === 長庚大學 === 生物醫學研究所 === 99 === Abstract Collapsin response mediator protein-2（CRMP-2）is a cytosolic phosphorylated protein. CRMP-2 is known to participate in the processing of neural development and differentiation, via regulation of neuron axonal outgrowth, elongation, and neuronal polarization. In a previous study, we used a polyclonal antibody, C17, which can recognize CRMP-2 C-terminus, to discover the existence of CRMP-2 long form （CRMP-2L）in colorectal carcinoma（CRC）cell line SW480 using mass spectrometric analysis and genome sequence search. The additional 118 amino acids at the N-terminus of CRMP-2L is the major difference from CRMP2, and both isoforms are encoded from the same gene by alternative splicing. Our previous study also indicated that CRMP-2 could be a novel potential biomarker of CRC. To investigate whether CRMP-2L, which has the same C-terminus with CRMP-2, is also overexpressed in CRC, we successfully generated two polyclonal antibodies（anti-N15 and anti-2LN）specifically recognized amino acids 1-15 and 1-118, respectively, of the N-terminus of CRMP-2L to analyze its expression level in CRC specimens. The result showed that CRMP-2L was highly overexpressed in CRC tumor cells（n = 163）compared to the adjacent non-tumor epithelial cells. We further used the in-house polyclonal antibodies to establish a sandwich ELISA and a microbead-based assay （Bioplex assay）for quantifying CRMP-2L levels in plasma samples from CRC patients. We found that the plasma CRMP-2L levels showed no significant difference between CRC patients and healthy controls. Finally, using expression plasmids of CRMP-2 and CRMP-2L and SW480 cells study materials, we observed that CRMP-2, but not CRMP-2L, can promote CRC cells migration in transwell assay.