Apical membrane expression of distinct sulfated glycans represents a novel marker of cholangiolocellular carcinoma

Abstract

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver neoplasm, followed by hepatocellular carcinoma. ICC can be further subclassified as (i) perihilar and (ii) peripheral types, the latter histologically resembling small-sized intrahepatic bile ducts, such as interlobular bile ducts, cholangioles/ductules and the canals of Hering. Cholangiolocellular carcinoma (CoCC), now classified by the World Health Organization as a subtype of combined hepatocellular-cholangiocarcinoma, is currently regarded as a subtype of peripheral-type ICC. The present study was undertaken to determine whether sulfated glycans recognized by the MECA-79 monoclonal antibody could serve as a CoCC marker. Using immunohistochemistry, we show that MECA-79 sulfated glycans are preferentially expressed at the apical membrane of cholangiocytes found in small-sized intrahepatic bile ducts in normal liver and in canalicular structures formed in CoCC. We also report that apical membrane MECA-79 sulfated glycan expression colocalizes with that of mucin 1 (MUC1) core proteins. We also present immunoblotting of Chinese hamster ovary cells overexpressing FLAG-tagged MUC1 to show that MUC1 serves as a MECA-79 scaffold. Furthermore, we report that SSP-25 human ICC cells overexpressing N-acetylglucosamine-6-O-sulfotransferase 2 (GlcNAc6ST-2), but not GlcNAc6ST-1, exhibit membrane expression of MECA-79 sulfated glycans, suggesting that GlcNAc6ST-2 catalyzes MECA-79 epitope biosynthesis in cholangiocytes. Moreover, both wild-type and GlcNAc6ST-1 knockout mice exhibit apical membrane MECA-79 expression in small-sized intrahepatic bile ducts, namely interlobular bile ducts, whereas MECA-79 expression was completely absent in comparable tissues from GlcNAc6ST-1 and GlcNAc6ST-2 double knockout mice. These data collectively indicate that apical membrane localization of MUC1 proteins decorated with GlcNAc6ST-2-dependent MECA-79 sulfated glycans may mark cholangiocytes with cholangiolar/ductular differentiation and could serve as a useful CoCC marker.

Carbohydrate Sulfotransferase 4 Inhibits the Progression of Hepatitis B Virus-Related Hepatocellular Carcinoma and Is a Potential Prognostic Marker in Several Tumors

“…We also analyzed the mRNA levels of CHST4 in 34 different types of human tumors. Consistent with previous studies, we found that the expression of CHST4 mRNA was higher in cholangiocarcinoma (24), colon adenocarcinoma (18), and gastric adenocarcinoma (22), and we partially verified this conclusion immunohistochemically. We also found that tumor expression of CHST4 at the mRNA and protein level is only partially consistent.…”

“…Additionally, in those with early-stage uterine corpus and cervical cancer, serum CHST4 expression was higher than that of cancer antigen 125 (CA125) and squamous cell carcinoma antigen (SCC) (21). CHST4 expression is also elevated in gastric cancer tissues (22), urothelial bladder carcinoma (23), cholangiolocellular carcinoma (24), and Opisthorchis viverrini (OV)-related intrahepatic cholangiocarcinoma (25), and the CHST4 promoter is hypermethylated in HBV-HCC (26). In gliomas, CHST4 was shown to have a high frequency of mutant alleles and amplifications and was related to poor prognosis (27).…”

Mucins: the Old, the New and the Promising Factors in Hepatobiliary Carcinogenesis

“…Recent studies showed colocalization of MECA-79 (a cholangiocyte marker) and MUC1 on apical membrane of cholangiocytes with cholangial/ductular differentiation. Hence, CoCCs are also regarded as a subtype of peripheral-type iCC [110]. On the other hand, the most recent molecular research indicates that CoCCs are distinct biliary-derived entities associated with chromosomal stability and active TGF-β signalling, without any traits of the HCCs [111].…”

“…Cholangiocarcinoma (currently type 2 IPNB) is also anatomically classified into perihilar and distal types of iCC [95,96,121,124]. Hilar carcinoma (called Klatskin tumour) and peripheral CC can be distinguished among iCCs, with both previously noted to exhibit mucin production [95,110]. Both subtypes of iCC are thought to arise from topologically different IBDs [107].…”

A case of intrahepatic cholangiocarcinoma that was difficult to diagnose prior to surgery: A case report

“…In a previous study, CoCC did not exhibit mucin production, although ICC did (25). Immunohistochemically, luminal EMA expression and positive CD56 are observed in CoCC, whereas cytoplasmic EMA expression and negative CD56 expression are usually observed in ICC (26). The histopathological features of these tumors are described in Table II.…”