Rapid Communication
Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Mar 14, 2008; 14(10): 1588-1591
Published online Mar 14, 2008. doi: 10.3748/wjg.14.1588
Colorectal carcinoma-associated antigen Ca-Hb3 detected by one-dimensional SDS-polyacrylamide gel electrophoresis and liquid chromatography-tandem mass spectrometry
Shuo Sun, Feng-Jie Guo, Yong-Qing Tong, Jian-Gao Zhu, Guan-Cheng Li
Shuo Sun, Feng-Jie Guo, Yong-Qing Tong, Jian-Gao Zhu, Guan-Cheng Li, Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan Province, China
Author contributions: Sun S, Zhu JG, and Li GC designed the study; Sun S and Guo FJ performed the research; Tong YQ analyzed the data; Sun S, Guo FJ, and Li GC wrote the paper.
Correspondence to: Professor Guan-Cheng Li, Cancer Research Institute, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha 410078, Hunan Province, China. libsun@public.cs.hn.cn
Telephone: +86-731-4805445
Fax: +86-731-2355042
Received: August 2, 2007
Revised: December 6, 2007
Published online: March 14, 2008
Abstract

AIM: To comprehensively identify the proteins of tumor relative antigen Ca-Hb3 recognized by colorectal carcinoma monoclonal antibody Hb3.

METHODS: Ca-Hb3 was isolated by SDS-polyacrylamide gel electrophoresis (PAGE) followed by digestion with trypsin. Trypsin peptides were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The proteins identified by mass spectrometry were analyzed using bioinformatics.

RESULTS: Ca-Hb3 was identified as a CKAP4-like protein by Nano HPLC tandem mass spectrometry analysis. The molecular weight of CKAP4-like protein was 62.02 kDa, including one hydrophobic region, one transmembrane domain, five coiled coils, four glycosylation sites and forty-nine phosphorylation sites. CKAP4-like protein had a high homogeneity with DeltaNp63α. The characteristic expression of DeltaNp63α that is considered a potential oncogene in the isoforms of p63 was similar to that of Ca-Hb3.

CONCLUSION: Ca-Hb3 is probably a CKAP4-like protein, belonging to DeltaNp63α isoform of p63 family.

Keywords: Colorectal neoplasm, Monoclonal antibody, Antigen, Mass spectrometry, p63