Ectopic expression of N-acetylglucosamine 6-O-sulfotransferase 2 in chemotherapy-resistant ovarian adenocarcinomas

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

Carbohydrate sulfotransferase 4 (CHST4) plays an important role in lymphocyte homing and is abnormally expressed in several cancer types; however, its precise function in tumor development and progression is unknown. Here we confirm that CHST4 is aberrantly expressed in various tumor subtypes. In particular, we found that CHST4 expression was downregulated in hepatitis B virus-related hepatocellular carcinoma (HBV-HCC) tumors compared to paired normal tissue. We also showed that CHST4 overexpression inhibited the proliferation and metastasis of HCC cells in vitro. Clinically, CHST4 was identified as an independent prognostic factor for HBV-HCC patients. We further illuminated the anti-tumor role and mechanism of CHST4 in HBV-HCC by constructing a FENDRR–miR-10b-5p–CHST4 competing endogenous RNA network. We found that downregulation of CHST4 expression may promote HBV expression and regulate ribonucleoprotein complex biogenesis to promote malignant behaviors in HBV-HCC. CHST4 may also recruit CD4+ T cells, macrophages, dendritic cells, and neutrophils into the tumor microenvironment to inhibit the progression of HBV-HCC. Overall, our findings suggest that CHST4 acts as a tumor suppressor in HCC-HBV and represents a potential diagnostic and therapeutic target.

Silencing HS6ST3 inhibits growth and progression of breast cancer cells through suppressing IGF1R and inducing XAF1

Heparan sulfate 6-O-sulfation is biologically edited by 6-O-sulfotransferases (HS6STs) within heparan sulfate chains. Three isoforms of HS6ST have been identified. These enzymes are found to be differentially expressed in a variety of tissues. Recently, several studies have shown that dysregulation of 6-O-sulfotransferases could be involved in tumorigenesis of several cancers. This study aimed to analyze the expression and function of HS6ST3 in breast cancer. HS6ST3 was found up-regulated in T47D, MCF7 and MDA-MB231 breast cancer cell lines. HS6ST3 was then silenced in T47D and MCF7 using siRNA. Silencing HS6ST3 diminished tumor cell growth, migration and invasion, but enhanced cell adhesion and apoptosis in breast cancer. Gene microarray analysis revealed that silencing HS6ST3 significantly changed the expression of IGF1R and XAF1 in breast cancer cells. Further functional studies showed that the cellular processes were mediated by IGF1R and XAF1 after silencing HS6ST3 in breast cancer cells. Together these results indicate that HS6ST3 might be involved in the tumorigenesis of breast cancer and it could be a promising target in breast cancer therapy.

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

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.

High endothelial venule-like vessels and lymphocyte recruitment in diffuse sclerosing variant of papillary thyroid carcinoma

Diffuse sclerosing variant of papillary thyroid carcinoma (DSPTC) is a rare subtype of papillary thyroid carcinoma with a high incidence of lymph node metastasis. One of its characteristic histological features is the presence of dense lymphocyte infiltrates; however, how these lymphocytes are recruited in this pathological setting remains unclear. Here, we analysed 17 DSPTC cases immunohistologically for cell adhesion molecules expressed on endothelial cells. We found that venules morphologically similar to high endothelial venules (HEVs) in secondary lymphoid organs were induced in lymphoid aggregates in DSPTC, and such HEV-like vessels expressed 6-sulfo sialyl Lewis X (sLeX) glycans as well as intercellular adhesion molecule 1 (ICAM-1). Triple immunohistochemistry revealed that CD8⁺ cytotoxic T cells were the major lymphocyte subset attached to the luminal surface of HEV-like vessels. sLeX-type glycans were also expressed on DSPTC carcinoma cells, which in binding assays were decorated with E-selectin•IgM chimaeras calcium-dependently. These findings collectively suggest that 6-sulfo sLeX glycans, together with ICAM-1, on HEV-like vessels may function to recruit CD8⁺ cytotoxic T cells in DSPTC. Additionally, sLeX-type glycans on carcinoma cells might partly contribute to highly metastatic properties of DSPTC through interaction with E-selectin expressed on endothelial cells.

A potential role for 6-sulfo sialyl Lewis X in metastasis of bladder urothelial carcinoma

OBJECTIVES

It is widely accepted that sialyl Lewis X (sLeX) and sialyl Lewis A (sLeA, also known as CA 19-9) glycans expressed on cancer cells function in E-selectin-mediated metastasis. Recently, it was reported that 6-sulfo sLeX glycans detected by the MECA-79 monoclonal antibody are expressed in roughly a quarter of gastric adenocarcinoma cases, and that these cases show a poorer prognosis than MECA-79-negative cases do. The present study was undertaken to assess expression of 6-sulfo sLeX glycans in bladder urothelial carcinoma and evaluate potential clinical implications.

MATERIALS AND METHODS

We analyzed 78 specimens representing bladder urothelial carcinoma, as well as 4 bladder urothelial carcinoma cell lines, by immunostaining with a battery of anticarbohydrate antibodies. We also undertook an E-selectin·IgM chimera binding assay to assess E-selectin binding to 6-sulfo sLeX expressed on bladder urothelial carcinoma cells and performed reverse transcription polymerase chain reaction and complementary DNA transfection to determine which N-acetylglucosamine-6-O-sulfotransferases function in 6-sulfo sLeX biosynthesis in those cells. Finally, we performed double-immunofluorescence staining for MECA-79 and either CD3 or CD8 to evaluate potential association between high endothelial venule (HEV)-like vessels and tumor-infiltrating T lymphocytes.

RESULTS

6-Sulfo sLeX glycans were expressed in ~20% of bladder urothelial carcinoma cases, particularly in plasmacytoid and micropapillary variants. Positive cells were also bound by E-selectin·IgM chimeras in a calcium-dependent manner. Transcripts encoding N-acetylglucosamine-6-O-sulfotransferase-2 were detected preferentially in HT-1197 bladder urothelial carcinoma cells expressing 6-sulfo sLeX, and transfection of the enzyme complementary DNA into HT-1376 cells, which do not express 6-sulfo sLeX glycans, resulted in cell surface expression of 6-sulfo sLeX. Furthermore, 6-sulfo sLeX glycans were expressed in HEV-like vessels induced in and around lymphocyte aggregates formed near carcinoma cell nests. These HEV-like vessel-associated tumor-infiltrating lymphocytes were composed primarily of CD3(+) T cells, with a fraction of CD8(+) cytotoxic T cells.

CONCLUSIONS

Our findings indicate that 6-sulfo sLeX glycans likely play 2 roles in bladder urothelial carcinoma progression: one in lymphocyte recruitment to enhance antitumor immune responses, and the other in E-selectin-mediated tumor cell adhesion to vascular endothelial cells, which is potentially associated with metastasis.

N-Acetylglucosamine 6-O-sulfotransferase-2 as a tumor marker for uterine cervical and corpus cancer

N-Acetylglucosamine 6-O-sulfotransferase-2 (GlcNAc6ST2) is ectopically expressed in ovarian mucinous and clear cell adenocarcinoma [Kanoh et al., Glycoconj J 23:453-460, 2006]. Here we studied whether GlcNAc6ST2 protein can be detected in sera from patients with gynecological cancers and could serve as a tumor marker. First, we created a monoclonal antibody and polyclonal antiserum against GlcNAc6ST2. These antibodies were specific for GlcNAc6ST2, as shown by Western blot analysis and immunoprecipitation. Using these antibodies, we constructed a sandwich ELISA method for detecting GlcNAc6ST2 in the serum. GlcNAc6ST2 provided lower positive rates for ovarian cancer than CA125, but higher positive rates for uterine cervical and corpus cancer than SCC antigens and CA125, respectively. A significantly higher percentage of stage I uterine cervical and corpus cancers were positive for GlcNAc6ST2 than for SCC antigens and CA125, respectively. GlcNAc6ST2 could therefore be a good serological marker for detecting early-stage uterine cervical and corpus cancers.