Identification of a novel type of CA19-9 carrier in human bile and sera of cancer patients

An implication of the involvement in nonsecretory exocytosis

Naofumi Uozumi, Congxiao Gao, Tomoko Yoshioka, Miyako Nakano, Kenta Moriwaki, Tsutomu Nakagawa, Tomomi Masuda, Makoto Tanabe, Eiji Miyoshi*

*Corresponding author for this work

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Carbohydrate antigen 19-9 (CA19-9) is a well-known tumor marker for pancreatic cancer. Although the CA19-9 level is measured using anti-sialyl Lewis A antibodies, it remains unknown which molecules carry CA19-9 other than mucins. Here we report the identification and characterization of a novel type of CA19-9 carrier, BGM (bile globular membrane), which is thought to exist in normal bile and to be secreted into sera of patients with pancreatic cancer. We purified the BGM from bile juice using a β-casein column because surface plasmon resonance analysis could detect such carrier vesicles binding to β-casein in sera of patients with pancreatic cancer. We identified characteristic molecules for BGM such as AHNAK (desmoykoin) and a novel golgin family member, CABIN (CAsein Binding domain integral protein with golgIN motif) by mass spectmetry analysis. BGM was detected in the sera of patients with pancreatic cancer as well as athymic mice with transplanted pancreatic cancer cells. Down regulation of CABIN inhibited the secretion of CA19-9 on BGM in pancreatic cancer cell lines. We measured and visualized BGM in sera of patients with cancer. Thus, BGM might be another CA19-9 carrier (glyco-lipids on membrane vesicles) other than mucins and could be applied to the diagnosis of pancreatic cancer.

Original languageEnglish
Pages (from-to)6345-6353
Number of pages9
JournalJournal of Proteome Research
Volume9
Issue number12
DOIs
Publication statusPublished - 3 Dec 2010

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