Alpha1,2fucosylation is a superior predictor of postoperative prognosis for colorectal cancer compared with blood group A, B, or sialyl Lewis X antigen generated within colorectal tumor tissues

(Sialyl)Lewis Antigen Expression on Glycosphingolipids, N-, and O-Glycans in Colorectal Cancer Cell Lines is Linked to a Colon-Like Differentiation Program

Alterations in the glycomic profile are a hallmark of cancer, including colorectal cancer (CRC). While, the glycosylation of glycoproteins and glycolipids has been widely studied for CRC cell lines and tissues, a comprehensive overview of CRC glycomics is still lacking due to the usage of different samples and analytical methods. In this study, we compared glycosylation features of N-, O-glycans, and glycosphingolipid glycans for a set of 22 CRC cell lines, all measured by porous graphitized carbon nano-liquid chromatography-tandem mass spectrometry. An overall, high abundance of (sialyl)Lewis antigens for colon-like cell lines was found, while undifferentiated cell lines showed high expression of H blood group antigens and α2-3/6 sialylation. Moreover, significant associations of glycosylation features were found between the three classes of glycans, such as (sialyl)Lewis and H blood group antigens. Integration of the datasets with transcriptomics data revealed positive correlations between (sialyl)Lewis antigens, the corresponding glycosyltransferase FUT3 and transcription factors CDX1, ETS, HNF1/4A, MECOM, and MYB. This indicates a possible role of these transcription factors in the upregulation of (sialyl)Lewis antigens, particularly on glycosphingolipid glycans, via FUT3/4 expression in colon-like cell lines. In conclusion, our study provides insights into the possible regulation of glycans in CRC and can serve as a guide for the development of diagnostic and therapeutic biomarkers.

A novel genotyping method for rapid identification of the Le gene to select patients for diagnosis with CA19-9

BACKGROUND

The antigenic determinant of CA19-9 is synthesized by the α1,3/4fucosyltransferase encoded by the Le gene in the Lewis blood group system. Accordingly, a diagnosis with CA19-9 is not appropriate forLe-negative patients who possess the Le gene-mutated le alleles homozygously.

METHODS

A Le gene-specific PCR was undertaken to determine c59T>G by using a set of tag-sense and biotin-labeled anti-sense primers and a peptide nucleic acid-le-clamp which bound to G59 in the le alleles. Following mixing with streptavidin-coatedbluelatex beads, the PCR products were developed on a strip on which the complementary tag oligonucleotide to theLe gene-specific amplicon was immobilized.

RESULTS

When the PCR products were developed on the strip, a clear line was rapidly observed in Le-positive but not in Le-negative individuals. In contrast, a significant number of cancer patients with Lewis-negative phenotype were found to possess CA19-9, while they were specifically genotyped asLe/-. No contradictory results were observed in cancer patients (n = 315) with respect to their Lewis genotypes and CA19-9 levels.

CONCLUSIONS

c59T>G occurred commonly in the le alleles could be specifically and rapidly identified by the present method. This method appeared to be relevant forselecting cancer patientsto bediagnosed with CA19-9.

Staining of E-selectin ligands on paraffin-embedded sections of tumor tissue

Background

The E-selectin ligands expressed by cancer cells mediate adhesion of circulating cancer cells to endothelial cells, as well as within tissue microenvironments important for tumor progression and metastasis. The identification of E-selectin ligands within cancer tissue could yield new biomarkers for patient stratification and aid in identifying novel therapeutic targets. The determinants of selectin ligands consist of sialylated tetrasaccharides, the sialyl Lewis X and A (sLe^X and sLe^A), displayed on protein or lipid scaffolds. Standardized procedures for immunohistochemistry make use of the antibodies against sLe^X and/or sLe^A. However, antibody binding does not define E-selectin binding activity.

Methods

In this study, we developed an immunohistochemical staining technique, using E-selectin-human Ig Fc chimera (E-Ig) to characterize the expression and localization of E-selectin binding sites on paraffin-embedded sections of different cancer tissue.

Results

E-Ig successfully stained cancer cells with high specificity. The E-Ig staining show high reactivity scores in colon and lung adenocarcinoma and moderate reactivity in triple negative breast cancer. Compared with reactivity of antibody against sLe^X/A, the E-Ig staining presented higher specificity to cancer tissue with better defined borders and less background.

Conclusions

The E-Ig staining technique allows the qualitative and semi-quantitative analysis of E-selectin binding activity on cancer cells. The development of accurate techniques for detection of selectin ligands may contribute to better diagnostic and better understanding of the molecular basis of tumor progression and metastasis.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4410-x) contains supplementary material, which is available to authorized users.

Fucosylated Glycans in α1-Acid Glycoprotein for Monitoring Treatment Outcomes and Prognosis of Cancer Patients

One standard treatment option for advanced-stage cancer is surgical resection of malignant tumors following by adjuvant chemotherapy and chemoradiotherapy. Additionally, neoadjuvant chemotherapy may be applied if required. During the time course of treatments, patients are generally followed by computed tomography (CT) surveillance, and by tumor marker diagnosis. However, currently, early evidence of recurrence and/or metastasis of tumors with a clinically relevant biomarker remains a major therapeutic challenge. In particular, there has been no validated biomarker for predicting treatment outcomes in therapeutic settings. Recently, we have looked at glycoforms of serum α₁-acid glycoprotein (AGP) by using a crossed affinoimmunoelectrophoresis with two lectins and an anti-AGP antibody. The primary glycan structures of AGP were also analyzed by a mass spectrometer and a novel software in a large number of patients with various cancers. Accordingly, the relative abundance of α1,3fucosylated glycans in AGP (FUCAGP) was found to be significantly high in cancer patients as compared with the healthy controls. Further, strikingly elevated levels of FUCAGP were found in patients with poor prognosis but not in patients with good prognosis. In the current study, levels of FUCAGP in serum samples from various cancer patients were analyzed and 17 patients including 13 who had undergone chemotherapy were followed for several years post operation. FUCAGP level determined diligently by using a mass spectrometer was found to change along with disease prognosis as well as with responses to treatments, in particular, to various chemotherapies. Therefore, FUCAGP levels measured during following-up of the patients after operation appeared to be clinically relevant biomarker of treatment intervention.

Distribution of ABO and Rh Blood Groups in Patients With Keratoconus: A Case-Control Study

Association of keratoconus (KC) with genetic predisposition and environmental factors has been well documented. However, no single study has investigated the possible relationship between ABO and Rh blood groups and KC.

METHODS

A case-control study was designed in a university hospital enrolling 214 patients with KC in the case group and equal number of age- and sex-matched healthy subjects in the control group. Primary characteristics, ABO blood group, and Rh factors were compared between the two groups. Topographic findings of KC eyes and the severity of the diseases were investigated according to the distribution of the blood groups.

RESULTS

Blood group O and Rh(+) phenotype were most frequent in both groups. There was no significant difference between the two groups in terms of ABO blood groups or Rh factors. Mean keratometery (K), central corneal thickness, thinnest corneal thickness, flat K, steep K, sphere and cylinder, spherical equivalent, and uncorrected visual acuity were all similar between ABO blood groups and Rh(+) and Rh(-) groups. However, the best spectacle-corrected visual acuity (BCVA) had the highest value in AB blood group (0.35 ± 0.22 logMAR, P=0.005). Moreover, the blood group AB revealed the highest frequency for grade 3 KC, followed by grades 1, 2, and 4 (P=0.003).

CONCLUSION

We observed no significant excess of any particular blood group among KC cases compared with healthy subjects. Except BCVA, none of the keratometric or topographic findings was significantly different between blood groups.

Blood group substances as potential therapeutic agents for the prevention and treatment of infection with noroviruses proving novel binding patterns in human tissues

Blood group-related glycans determining ABO and Lewis blood groups are known to function as attachment factors for most of the norovirus (NoV) strains. To identify binding specificity of each NoV, recombinant norovirus-like particles (VLPs) and human saliva samples with different ABO, Lewis phenotypes and secretor status have been commonly applied. When binding specificities of VLPs prepared from 16 different genotypes of NoVs in GI and GII genogroups were characterized in samples of human gastric mucosa compared to human saliva based on blood group phenotypes, considerable differences were observed for several strains. Novel binding specificities determined by an ELISA using preparations from human gastric mucosa were also ascertained by immunohistochemical analyses using human jejunal mucosa, widely believed to be susceptible to NoV infection. Further, A, B and O(H) blood group substances prepared from porcine and squid tissues were found to be effective for preventing ABO blood group-specific binding of VLPs to both saliva and mucosa samples. Therefore, these blood group substances might have potential for the prevention and treatment of NoV infection.

Suppression of FUT1 attenuates cell proliferation in the HER2-overexpressing cancer cell line NCI-N87

Lewis Y (LeY) antigen is an oligosaccharide that is highly expressed at the cell surface in various human cancers. Increased LeY expression activates epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) and promotes cell proliferation in EGFR-overexpressing cells. However, the effect of downregulation of LeY expression on cell proliferation in HER2-overexpressing cells remains unknown. FUT1 encodes α1,2-fucosyltransferase, a key enzyme for LeY synthesis. We knocked down FUT1 by short interfering RNA (siRNA) in four HER2-overexpressing human cancer cell lines, including NCI-N87, MKN7, SKBr3 and BT474. We investigated whether downregulation of LeY and alteration in the glycosylation status of these cells affect cell proliferation and HER2 activation. Knocking down FUT1 expression markedly inhibited proliferation of NCI-N87, which highly expressed EGFR and was sensitive to EGFR deprivation. Furthermore, FUT1 siRNA downregulated the total amount of HER2 protein, phosphorylation of HER2 and EGFR, and phosphorylation of extracellular signal-regulated kinase (ERK) in this cell line. Moreover, the marked downregulation of phosphorylation of HER2 and ERK was observed following short-time EGF-stimulation. These effects were not observed in the other three cell lines. Our results suggest that knockdown of FUT1 downregulates HER2 signaling via EGFR downregulation. FUT1 may serve as a new molecular target for HER2-overexpressing human cancers with activated EGFR signaling.

The hypothesis on function of glycosphingolipids and ABO blood groups revisited

Twenty-five years ago the author proposed new ideas of glycoprotein (GPs) and glycosphingolipid (GSLs) functions at the cell membrane. The GPs, apart from their glycan carrying capacity, were assumed to have specific, protein associated, functions. In contrast, GSLs such as those of globo and neolacto/lacto series, were considered to be energetically cheap membrane packing substances, filling in membrane spaces not covered with functional GPs. The terminal carbohydrate structures of the neolacto/lacto GSLs, i.e., sialic acid residues and ABH glycotopes, were postulated to have either regulatory or protective functions, respectively. A special active role was ascribed to terminal β-galactosyl residues of GSLs and GPs. Gangliosides were considered to be functional GSLs. In the present review the author discusses these old ideas in context of the contemporary knowledge and comes to the conclusion that they have not aged.

α(1,2)fucosylation in human colorectal carcinoma

Lewis(b) and Lewis(y) (Le) antigens are known to be elevated in colorectal tumours. Alterations in the catalytic behaviour of GDP-L-fucose:β-D-galactoside α(1,2)fucosyltransferase [α(1,2)FT, EC: 2.4.1.69], the key enzyme in their synthesis, have been suggested as being responsible for these changes. In particular, an aberrant tumour-specific α(1,2)FT activity that converts Le(a) and Le(x) to Le(b) and Le(y) determinants, respectively, has been reported in colorectal cancer tissues. To clarify the catalytic function of this enzyme during colorectal tumorigenesis, we analyzed α(1,2)FT activity levels in healthy and tumour colon specimens using different acceptor substrates and determined the kinetic properties of the enzyme. To complete the study, the aberrant Le(a)/Le(x) α(1,2)fucosylation was determined in healthy and tumour colorectal tissues. A correlation analysis between the activity levels and various standard clinicopathological features, such as tumour stage, was also carried out to elucidate the role of these activities in tumour progression. The results obtained confirm the enhanced α(1,2)fucosylation in colorectal neoplastic tissues and the importance of the aberrant Le(a)/Le(x) α(1,2)FT activity in this increase. However, taking into account the high levels of Le(a)/Le(x) fucosylation observed in healthy control tissues, we must rule out the idea of a colorectal tumour-specific α(1,2)FT. On the other hand, no significant association was observed between α(1,2)FT activity levels and the clinicopathological characteristics. Overall, our results suggest that α(1,2)FT activity plays a critical role in the accumulation of Le(b) and Le(y) antigens in human colorectal carcinoma.

Novel sugar-cholestanols as anticancer agents against peritoneal dissemination of tumor cells

Chemically synthesized sugar-cholestanols with mono-, di-, and tri-saccharides attached to cholestanol showed strong inhibiting activity against the proliferation of colorectal and gastric cancer cells. In contrast, cholestanol without sugar moieties was totally ineffective. Furthermore, when cancer cells were exposed to GlcNAcRbetacholestanol (R=(-) or beta1-3Gal), the compound was rapidly taken up via the lipid rafts/microdomains on the cell surface. The uptake of sugar-cholestanol in mitochondria increased gradually and was followed by the release of cytochrome c from mitochondria and the activation of apoptotic signals through the mitochondrial pathway and the caspase cascade, leading to apoptotic cell death, characterized by DNA ladder formation and nuclear fragmentation. Additionally, the examination of GlcNAcRbetacholestanol in a mouse model of peritoneal dissemination showed a dramatic reduction of tumor growth (P < 0.003) and prolonged mouse survival time (P<0.0001). Based on these observations, we believe that the sugar-cholestanols described here have clinical potential as novel anticancer agents.