Enhanced expression of sulfatide, a sulfated glycolipid, in well-differentiated endometrial adenocarcinoma

Characterization of a novel glycolipid with a difucosylated H-antigen in human blood group O erythrocytes with monoclonal antibody HMMC-1 and its detection in human uterine cervical carcinoma tissues

Humanized monoclonal antibody HMMC-1 established by immunizing transchromosomal mice with a human uterine endometrial cancer cell line has been found to react with the H-antigen carried on core l O-glycans through cotransfection of glycosyltransferases for O-glycans and inhibition of antibody-binding with synthetic oligosaccharides. However, direct binding analysis of an antibody against glycosphingolipids from human erythrocytes with different ABO blood groups revealed that it was able to bind selectively with polar glycolipids in blood group O, but not blood group A, B and AB erythrocytes. Unexpectedly, typical monofucosylated H-glycolipids, IV²Fucα-nLc₄Cer and VI²Fucα-nLc₆Cer, which are the precursors for A and B-glycolipids, and were present not only in blood group O, but also A, B and AB-erythrocytes, were not the antigens for the HMMC-1 antibody. The antigen comprised less than 0.001% of the total glycolipids in blood group O-erythrocytes, and was purified by conventional silica gel column chromatography. Structural determination by permethylation, GC-MS, and ESI-TOFMS demonstrated that the structure was a novel glycolipid with a difucosylated H-antigen, Fucα1-2Galβ1-4GlcNAcβ1-3Gal(2-1αFuc)β1-4GlcNAcβ1-3Galβ1-4GlcNAcβ1-3Galβ1-4Glcβ1-1'Cer, VI²,VIII²(Fucα)₂-nLc₈Cer, whose terminal difucosylated structure was the epitope of the HMMC-1 antibody. The HMMC-1 glycolipid was detected in five out of 29 tissues from patients suffering from uterine cervical carcinomas, irrespective of their ABO-blood groups.

Serum concentrations of soluble (s)L- and (s)P-selectins in women with ovarian cancer

Introduction

The aim of the study was to compare serum concentration of soluble L- and P-selectins in women with ovarian cancer (OC) and healthy controls, and to investigate sL- and sP-selectin levels with regard to clinical and pathological parameters. Correlation analysis was used to measure the following: sL- and sP-selectin concentration and Ca125; sP-selectin and platelet concentrations; and sL-selectin and serum leukocyte levels in women with OC.

Material and methods

The study included 29 patients with OC and 23 healthy controls. Serum concentrations of sL- and sP-selectins were measured in all subjects. Routine diagnostic tests: CBC and USG (both groups) and Ca125 (study group) were performed.

Results

Significantly higher serum concentrations of sL- and sP-selectins were found in the study group as compared to controls. Lower levels of serum sL-selectin were observed in women with poorly-differentiated OC (G3) and advanced stages of the disease (FIGO III, IV), but the results were statistically insignificant. No statistically significant relationship was detected between sP-selectin serum concentration in women with OC and tumour differentiation, histological type, and stage of the disease. No significant correlation was found between sL- and sP-selectins and Ca125 levels. A weak correlation was found between serum concentration of sP-selectin in women with OC and platelet count. No statistically significant correlation was observed between sL-selectin concentration and serum leukocyte levels in women with OC.

Conclusions

The analysis of sL- and sP-selectin concentrations may be a useful tool in the diagnosis of OC. The levels of sL-selectin decrease with disease progression.

Effective Selection of a Well-Differentiated Type of Human Uterine Endometrial Carcinoma Cells by Transfection of the Sulfotransferase Gene and Possible Association of Sulfoglycolipids With Well-Differentiated Phenotypes

OBJECTIVES

Sulfatide has been shown to be characteristically increased on the apical surface of the normal endometrium at the secretory phase, and to be related with the formation of the glandular structure and the secretion of mucin from glands for the implantation of a fertilized egg. Additionally, sulfatides are expressed in the well-differentiated type, but not in the poorly differentiated type, of endometrial carcinomas. This suggests that sulfatides are a molecular marker of differentiated phenotypes. To further elucidate the biological significance of sulfoglycolipids, we transfected the sulfotransferase gene into endometrial carcinoma-derived cells without sulfoglycolipids and compared their glycolipid compositions and phenotypes with those of the original cells.

MATERIALS AND METHODS

The glycolipid sulfotransferase gene was transfected into endometrial carcinoma-derived SNG-II cells, the resultant transfected cells being found to frequently form a domelike structure, and some of them were selected as SNG-II-GST cells. We compared the glycolipid compositions and phenotypes of SNG-II and SNG-II-GST cells.

RESULTS

Although the original SNG-II cells grew in a paving stone pattern, SNG-II-GST cells formed a domelike structure. SNG-II-GST cells exhibited high GST activity and contained sulfoglycolipids, IISO3-LacCer and IISO3-Gg3Cer, which were not found in SNG-II cells. The amounts of sulfoglycolipids in SNG-II-GST cells were 1.5 times higher than those of gangliosides, and the proportions of LacCer and GM3 in SNG-II-GST cells were greatly different from those in SNG-II cells. SNG-II and SNG-II GST cells exhibited poorly differentiated and well-differentiated phenotypes on histochemical examination of cancerous nodules in nude mice. However, by means of an oxygen electrode, SNG-II-GST cells were found to be more resistant to anticancer drugs than SNG-II cells.

CONCLUSION

Enhanced expression of sulfoglycolipids in poorly differentiated cells is a feasible means of selecting well-differentiated ones, and sulfoglycolipids are involved in the well-differentiated phenotype like those in the normal endometrium at the secretory phase.

Immunization of A4galt-deficient mice with glycosphingolipids from renal cell cancers resulted in the generation of anti-sulfoglycolipid monoclonal antibodies

In this study, we immunized Gb3/CD77 synthase gene (A4galt) knockout (KO) mice with glycosphingolipids (GSLs) extracted from 3 renal cell cancer (RCC) cell lines to raise monoclonal antibodies (mAbs) reactive with globo-series GSLs specifically expressed in RCCs. Although a number of mAbs reactive with globo-series GSLs were generated, they reacted with both RCC cell lines and normal kidney cells. When we analyzed recognized antigens by mAbs that were specifically reactive with RCC, but not with normal kidney cells at least on the cell surface, many of them turned out to be reactive with sulfoglycolipids. Eight out of 11 RCC-specific mAbs were reactive with SM2 alone, and the other 3 mAbs were more broadly reactive with sulfated glycolipids, i.e. SM3 and SM4 as well as SM2. In the immunohistochemistry, these anti-sulfoglycolipids mAbs showed RCC-specific reaction, with no or minimal reaction with adjacent normal tissues. Thus, immunization of A4galt KO mice with RCC-derived GSLs resulted in the generation of anti sulfated GSL mAbs, and these mAbs may be applicable for the therapeutics for RCC patients.

γδ T cell surveillance via CD1 molecules

γδ T cells are a prominent epithelial-resident lymphocyte population, possessing multi-functional capacities in the repair of host tissue, pathogen clearance, and tumor surveillance. Although three decades have now passed since their discovery, the nature of γδ T cell receptor (TCR)-mediated ligand recognition remains poorly defined. Recent studies have provided structural insight into this recognition, demonstrating that γδ T cells survey both CD1 and the presented lipid, and in some cases are exquisitely lipid specific. We review these findings here, examining the molecular basis for and the functional relevance of this interaction. We discuss potential implications on the notion that non-classical major histocompatibility complex (MHC) molecules may function as important restricting elements of γδ TCR specificity, and on our understanding of γδ T cell activation and function.