Expression of cell surface Lewis X and Y antigens and FUT4 mRNA is increased in Jurkat cells undergoing apoptosis

An Introduction to the Relationship Between Lewis x and Malignancy Mainly Related to Breast Cancer and Head Neck Squamous Cell Carcinoma (HNSCC)

Lewis x functions as an adhesion molecule in glycolipids and glycoproteins since it mediates homophilic and heterophilic attachment of normal and tumoral cells. During malignancy, altered glycosylation is a frequent event; accumulating data support the expression of Lewis x in tumors although controversial results have been described including its relationship with patient survival. This report has been developed as an introduction to the relationship between Lewis x expression and breast cancer and head and neck squamous cell carcinoma (HNSCC). Results obtained in our laboratory are presented in the context of the literature.

Lewis(y) antigen-mediated positive feedback loop induces and promotes chemotherapeutic resistance in ovarian cancer

The present study aimed to investigate the association between Lewis(y) antigen and chemoresistance in ovarian cancer and to elucidate the underlying molecular mechanisms. Lewis(y) expression in chemoresistant ovarian cancer tissues and cells was detected by immunohistochemistry. α1,2‑fucosyltransferase (FUT1) expression in different ovarian cancer chemotherapy-resistant cells was analyzed by reverse transcription-quantitative PCR (RT-qPCR). Genes differentially expressed in the chemoresistant and sensitive groups were screened using a gene chip followed by validation using RT-qPCR and western blot analysis. We found that Lewis(y) and FUT1 expression in ovarian cancer cells was significantly increased following the induction of drug resistance. The positive expression rate and intensity of Lewis(y) in ovarian cancer chemoresistant tissues were also significantly higher than those in the sensitive group. Compared with the non-resistant cell lines, the differentially expressed genes were mainly enriched in the terms related to the transmembrane receptor protein tyrosine kinase signaling pathway and positive regulation of cell proliferation. Interaction network analysis predicted genes participating in the regulation of apoptotic processes. The highly differential expression of Annexin A4 (ANXA4), BCL2 interacting killer (BIK), transmembrane 4 L six family member 4 (TM4SF4) and pleckstrin homology-like domain family A member 1 (PHLDA1) was validated using RT-qPCR in ovarian cancer cell lines. Finally, ANXA4 expression was increased at both the mRNA and protein level in the drug‑resistant cells, and in addition, ANXA4 contained a Lewis(y) structure. The expression of Bcl-2 and other anti-apoptotic proteins increased with the increase of Lewis(y) expression. After blocking Lewis(y) using an antibody, the expression of the involved signaling pathway and apoptosis-related proteins decreased significantly. These findings provide strong evidence that Lewis(y) is a component of the structure of the ANXA4 membrane protein. Its overexpression can abnormally activate signaling pathways and regulate the expression of a number of factors, forming a positive feedback loop to induce the chemoresistance of ovarian cancer cells, and ultimately promoting the progression of ovarian cancer.

Lewis-antigen-containing ICAM-2/3 on Jurkat leukemia cells interact with DC-SIGN to regulate DC functions

Dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) is an important C-type lectin and plays a critical role in the recognition of pathogens and self-antigens. It has recently been shown that DC-SIGN directly interacts with acute T lymphoblastic leukemia cells. However, the mechanism regulating DC-SIGN-dependent DC association as well as related functions is still elusive. Here we showed that DC-SIGN preferentially bound to a set of malignant T lymphocytes, including Jurkat, CCRF-HSB2 and CCRF-CEM. ICAM-2/3 on Jurkat cells appeared to be the responsible ligands and the block of ICAM-2/3 dramatically impaired DC-SIGN association. We also found that ICAM-2/3 bear a considerable amount of Lewis X, Lewis Y and Lewis A residues, which are important for DC-SIGN recognition. Furthermore, transcriptome analysis revealed an upregulation of fucosyltransferase 4 (FUT4) in Jurkat cells and downregulating FUT4 limited DC-SIGN binding, indicating a previously unappreciated role of FUT4 in the control of Lewis antigens on malignant T lymphocytes. In addition, the presence of Jurkat cells impaired DC maturation and the block of DC-SIGN improved Jurkat cell-mediated effects on DC function and T cell differentiation. Together, we provide evidence that DC-SIGN orients DC association with acute T lymphoblastic leukemia cells and orchestrates DC functions.

Lewis x Antigen is Associated to Head and Neck Squamous Cell Carcinoma Survival

Head and neck squamous cell carcinoma (HNSCC) is an aggressive disease with poor prognosis without appropriate prognostic markers. Previous research shows that Lewis antigens have been involved in carcinoma dissemination and patients´ survival. Fucosyl and sialyltransferases are the enzymes implicated in the Lewis antigens synthesis. The purpose of this study was to evaluate the prognostic utility of Lewis antigens in HNSCC. We conducted a prospective research including histological samples from 79 patients with primary HNSCC. Lewis x and sialyl Lewis x expression were detected by immunohistochemistry; patient's data, progression free, and overall survival were documented. A statistical correlation study of antigenic expression and patients´ histopathological variables was performed. Cox regression models with internal validation procedures were employed to analyze survival data. By immunohistochemistry, Lewis x was detected in 34/79 (43%) tumor samples, while sialyl Lewis x only in 11/79 (14%). Lewis x expression showed a positive correlation with tumor differentiation and a better overall survival for Lewis x + patients was detected. Moreover, multivariate Cox's regression analysis showed that Lewis x is an independent predictor of better overall survival. The in silico analysis supported the presence of deregulated fucosyl (FUT4) and sialyltransferase (ST3GAL4) in the Lewis synthetic pathway related to patient survival. These results suggest that Lewis x expression is associated with a better outcome in patients with HNSCC.

Ginsenoside Rg3-induced EGFR/MAPK pathway deactivation inhibits melanoma cell proliferation by decreasing FUT4/LeY expression

Malignant melanoma is a destructive and lethal form of skin cancer with poor prognosis. An effective treatment for melanoma is greatly needed. Ginsenoside Rg3 is a herbal medicine with high antitumor activity. It is reported that abnormal glycosylation is correlated with the tumor cell growth. However, the antitumor effect of Rg3 on melanoma and its mechanism on regulating glycosylation are unknown. We found that Rg3 did not only inhibit A375 melanoma cell proliferation in a dose-dependent manner, but also decreased the expression of fucosyltransferase IV (FUT4) and its synthetic product Lewis Y (LeY), a tumor-associated carbohydrate antigen (TACA). Knocking down FUT4 expression by siRNA dramatically reduced FUT4/LeY level and inhibited cell proliferation through preventing the activation of EGFR/MAPK pathway. Consistently, the inhibitory effect of the Rg3 and FUT4 knockdown on melanoma growth was also seen in a xenograft melanoma mouse model. In conclusion, Rg3 effectively inhibited melanoma cell growth by downregulating FUT4 both in vitro and in vivo. Targeting FUT4/LeY mediated fucosylation by Rg3 inhibited the activation of EGFR/MAPK pathway and prevented melanoma growth. Results from this study suggest Rg3 is a potential novel therapy agent for melanoma treatment.

Different effects of androgen on the expression of Fut1, Fut2, Fut4 and Fut9 in male mouse reproductive tract

The α-(1,2) fucosyltransferases (Fut1 and Fut2) and α-(1,3) fucosyltransferases (Fut4, Fut9) are responsible for the synthesis of Lewis X (LeX) and Lewis Y (LeY) conjugated to glycoproteins. We recently reported that these fucosyltransferases were differentially expressed in the reproductive tract of male mouse. Here, we studied the effect of androgen on fucosyltransferase expression through the use of mouse castration models. We found that Fut1 mRNA and Fut4 mRNA were upregulated, while Fut2 mRNA and Fut9 mRNA were downregulated by androgen in the caput epididymis. However, in the vas deferens and prostate, only Fut4 mRNA and Fut2 mRNA were respectively upregulated following exposure to androgen. In the seminal vesicle, all fucosyltransferases, with the exception of Fut9, were upregulated. We identified the androgen receptor binding sites (ARBSs) of Fut2, Fut4 and Fut9 in the caput epididymis. Luciferase assay for these ARBSs is able to provide an indication as to why Fut4 and Fut9 are differently expressed and regulated by androgen, although they catalyze the same α-(1,3) fucose linkage. Our study showed that androgen could differentially regulate the expression of these fucosyltransferases and provided an insight into the characteristic distribution of each fucosyltransferase responsible for LeX/LeY biosynthesis in the male reproductive tract.

Hepatic gene expression of Caucasian and African-American patients with obesity-related non-alcoholic fatty liver disease

BACKGROUND/AIM

There is increasing data suggesting that African Americans with NAFLD tend to have less progressive liver disease. The aim of this study is to assess differences in the hepatic gene expression of African-American and Caucasian patients with NAFLD who had undergone bariatric surgery.

METHODS

A total of 94 patients (81 NAFLD and 13 weight-matched controls with normal liver biopsy) were included. Of the entire cohort, 73 were Caucasians and 21 were African Americans. All patients were undergoing bariatric surgery. Two liver biopsies were obtained at the time of surgery. One biopsy was snap-frozen for gene expression and the other biopsy was stained for pathologic assessment. Liver biopsy confirmed that 24 patients from our cohort had NASH while 57 had only simple steatosis. Snap-frozen liver biopsy specimens of these patients were then used for the RNA extraction. cDNA probes were hybridized with customized microarray gene chips containing 5,220 relevant genes. Gene expression profiles were compared between groups using significance analysis of microarrays algorithm.

RESULTS

In comparison to all Caucasian patients, African-American patients had over-expression of EPB41L1, IGF2, FAH, ACSL4, FUT4, CYP3A (q values < 10(-4)). In comparison to Caucasian NAFLD patients, African-American NAFLD patients showed over-expression of EPB41L1 and ACSL4 genes. Finally, in comparison to Caucasian NASH patients, African-American NASH patients showed over-expression of GSTM 2, GSTM4 and GSTM5 as well as FH and ASCL4 genes. Some genes highlighted by this analysis, particularly cytochrome CYP3A and glutathione transferases GSTM2, 4, 5, were previously implicated in the pathogenesis of NASH.

CONCLUSION

African-American patients with biopsy-proven obesity-related NAFLD and NASH have a specific hepatic gene expression pattern that may explain their differences from Caucasian patients with NAFLD in developing progressive liver disease.

Lewis y antigen promotes the proliferation of ovarian carcinoma-derived RMG-I cells through the PI3K/Akt signaling pathway

BACKGROUND

Lewis y antigen is difucosylated oligosaccharide and is carried by glycoconjugates at cell surface. Elevated expression of Lewis y has been found in 75% of ovarian tumor, and the high expression level is correlated to the tumor's pathological staging and prognosis. This study was to investigate the effect and the possible mechanism of Lewis y on the proliferation of human ovarian cancer cells.

METHODS

We constructed a plasmid encoding alpha1,2-fucosyltransferase (alpha1,2-FT) gene and then transfected it into ovarian carcinoma-derived RMG-I cells with lowest Lewis y antigen expression level. Effect of Lewis y on cell proliferation was assessed after transfection. Changes in cell survival and signal transduction were evaluated after alpha-L-fucosidase, anti-Lewis y antibody and phosphatidylinositol 3-kinase (PI3K) inhibitor treatment.

RESULTS

Our results showed that the levels of alpha1,2-FT gene and Lewis y increased significantly after transfection. The cell proliferation of ovarian carcinoma-derived RMG-I cells sped up as the Lewis y antigen was increased. Both of alpha-L-fucosidase and anti-Lewis y antibody inhibited the cell proliferation. The phosphorylation level of Akt was apparently elevated in Lewis y-overexpressing cells and the inhibitor of PI3K, LY294002, dramatically inhibited the growth of Lewis y-overexpressing cells. In addition, the phosphorylation intensity and difference in phosphorylation intensity between cells with different expression of alpha1,2-FT were attenuated significantly by the monoantibody to Lewis y and by the PI3K inhibitor LY294002.

CONCLUSIONS

Increased expression of Lewis y antigen plays an important role in promoting cell proliferation through activating PI3K/Akt signaling pathway in ovarian carcinoma-derived RMG-I cells. Inhibition of Lewis y expression may provide a new therapeutic approach for Lewis y positive ovarian cancer.

Altered expression of glycoproteins on the cell surface of Jurkat cells during etoposide-induced apoptosis: shedding and intracellular translocation of glycoproteins

BACKGROUND

The glycoproteins on the cell surface are altered during apoptosis and play an important role in phagocytic clearance of apoptotic cells.

METHODS

We classified Jurkat cells treated with etoposide as viable and early apoptotic cells, late apoptotic cells or secondary necrotic cells based on propidium iodide staining and scattered grams and estimated the expression levels of glycoproteins on the cell surface.

RESULTS

The cell surface expression levels of intercellular adhesion molecules (ICAM)-2 and -3 on the apoptotic cells were markedly lower, while those of calnexin, calreticulin, and lysosome-associated membrane proteins (LAMP)-1 and -2 were significantly higher compared to non-apoptotic cells. These decreases in ICAM-2 and -3 on the apoptotic cell surface were reduced in the presence of metalloproteinase inhibitors and caspase inhibitors, respectively. Confocal microscopic analysis revealed that calnexin and calreticulin were assembled around fragmented nuclei of blebbed apoptotic cells.

CONCLUSIONS

These results suggest that alteration of glycoproteins on the cell surface during apoptosis is associated with shedding and intracellular translocation of glycoproteins.

Breast cancer humoral immune response: involvement of Lewis y through the detection of circulating immune complexes and association with Mucin 1 (MUC1)

Background

In cancer patients, MUC1 glycoprotein may carry Lewis y which could be involved in immune response. Purposes: 1- to evaluate the presence of Lewis y and MUC1 in circulating immune complexes (Lewis y/CIC and MUC1/CIC, respectively) and their correlation; 2- to analyze the possible presence of Lewis y in carbohydrate chains of tumoral MUC1 glycoprotein and 3- to correlate serum and tissue parameters considered.

Methods

Pretreatment serum and tissue breast samples from 76 adenocarcinoma, 34 benign and 36 normal specimens were analyzed. Anti-MUC1 and anti-Lewis y MAbs were employed. To detect Lewis y/CIC and MUC1/CIC, ELISA tests were developed; serum samples containing MUC1 were previously selected by Cancer Associated Serum Antigen (CASA). Immunoprecipitation (IP) was performed in 9 malignant, benign and normal samples and analyzed by SDS-PAGE and Western blot. Lewis y and MUC1 expression was studied by immunohistochemistry (IHC). Statistical analysis was performed employing principal component analysis (PCA), ANOVA, Tukey HSD, Chi square test and classical correlation (p < 0.05).

Results

By ELISA, Lewis y/IgM/CIC levels showed statistically significant differences between breast cancer versus benign and normal samples; mean ± SD values expressed in OD units were: 0.525 ± 0.304; 0.968 ± 0.482 and 0.928 ± 0.447, for breast cancer, benign disease and normal samples, respectively, p < 0.05. Lewis y/IgG/CIC did not show any statistically significant difference. MUC1/IgM/CIC correlated with Lewis y/IgM/CIC. By CASA, 9 samples with MUC1 values above the cut off were selected and IP was performed, followed by SDS-PAGE and Western blot; bands at 200 kDa were obtained with each MAb in all the samples. By IHC, with C14 MAb, 47.5%, 31% and 35% of malignant, benign and normal samples, respectively, showed positive reaction while all the samples were positive with anti-MUC1 MAb; in both cases, with a different pattern of expression between malignant and non malignant samples.

Conclusion

Our findings support that in breast cancer there was a limited humoral immune response through Lewis y/IgM/CIC levels detection which correlated with MUC1/IgM/CIC. We also found that Lewis y might be part of circulating MUC1 glycoform structure and also that Lewis y/CIC did not correlate with Lewis y expression.

Suppression of FUT1/FUT4 expression by siRNA inhibits tumor growth

Lewis Y (LeY) antigen is highly expressed in a variety of human carcinomas of epithelial cell origin. Recent studies suggest functional blockade of LeY may provide a novel therapeutic approach for the treatment of cancers. However, suppressing LeY expression by genetic manipulation and its impact on neoplastic cell proliferation has not been investigated. We report here that different fucosyltransferases (FUTs) were expressed with the greatest expression of fucosyltransferase I or IV (FUT1/4), the two key enzymes for the synthesis of LeY in human epidermoid carcinoma A431 cells. Knocking down FUT1/4 expression by short interfering RNA technique dramatically reduced the expression of FUT1/4 and LeY and inhibited cell proliferation through decreasing epidermal growth factor receptor (EGFR) signaling pathway. Treatment of A431 cells that were inoculated into the nude mice with FUT1 siRNA or FUT4 siRNA greatly impeded tumor growth. Suppressing FUT1/4 expression also blocked EGF-induced tyrosine phosphorylation of EGFR and mitogen-activated protein kinases. In conclusion, suppressing the expression of FUT1/4 by RNAi technology reduces the synthesis of LeY and inhibits cancer growth. It may serve as a potential methodology for the treatment of cancers that express LeY glycoconjugates.

Ultrastructural localization of glycodelin oligosaccharides Le-x and Le-y in human seminal vesicles by immunogold staining

Histo-blood group antigens Le-x and Le-y are oligosaccharidic terminals that characterize many glycoproteins in the human tissues. In seminal plasma, they are expressed as part of the so-called glycodelin S, which is suggested to regulate sperm capacitation/decapacitation. It has recently been demonstrated that the core protein of glycodelin S is secreted by seminal vesicles. Here we show that epithelial cells of human seminal vesicles also release the Le-x and Le-y antigens. The presence of these substances in secretory material was revealed by means of an immunogold staining method in normal surgical samples. The results suggest that glycodelin S is secreted by seminal vesicles in its finished glycosylated form. Moreover, antigen reactivity was also revealed associated with plasma membranes.

Increased expression of Lewis X and Y antigens on the cell surface and FUT 4 mRNA during granzyme B-induced Jurkat cell apoptosis

Cytotoxic T cells and natural killer cells play key roles in cell-mediated cytotoxicity and can induce apoptosis in virus-infected and malignant cells by releasing cytotoxic granules. In the current study, apoptosis was induced in Jurkat cells, a human T cell line, by delivering granzyme B into the cells using BioPORTER, a cationic lipid formulation. During granzyme B-induced apoptosis, there was an increase in the cell surface expression of Lewis X and Y antigens. To clarify the roles of initiator and executioner caspases in the expression of Lewis X and Y antigens, we treated Jurkat cells with granzyme B in the presence of caspase 3, 8, and 9 inhibitors. The results indicated that delivery of granzyme B into Jurkat cells induces apoptosis by activating caspase 3 and that caspase 3 but not caspase 8 and 9 plays a key role in enhancing the expression of Lewis X and Y antigens. Real-time PCR revealed that expression of the mRNAs for alpha1,3-fucosyltransferases FUT4 was increased at 3 h during granzyme B-induced apoptosis, while FUT9 mRNA expression gradually increased after 12 h. This increased expression of FUT4 mRNA occurred downstream of caspase 3 activation and resulted in the increased cell surface expression of Lewis X and Y antigens.

Alpha1,3 Fucosyltransferase-VII modifies the susceptibility of apoptosis induced by ultraviolet and retinoic acid in human hepatocarcinoma cells

The role of alpha1,3fucosyltransferase-VII (alpha1,3 FucT-VII) in cell apoptosis was studied in human hepatocellular carcinoma H7,721 cells. After the cells were transfected with alpha1,3 FucT-VII cDNA, the expression of apoptotic protease, procaspase-3, was decreased, while the anti-apoptotic proteins, phospho-PKB and phospho-Bad were increased as compared with mock (vector) transfected cells, indicating that alpha1,3FucT-VII is a potential anti-apoptotic factor in H7,721 cells. After "alpha1,3FucT-VII" cells were irradiated by UV to induce apoptosis, the anti-apoptotic potential of alpha1,3FucT-VII became more apparent, as evidenced by the less apoptotic cell % and active cleaved caspase-3, more phospho-p38 MAPK and JNK (two anti-apoptotic signaling molecules in H7,721 cells responsible to UV stress) when compared with the "Mock" cells. In contrast, "alpha1,3FucT-VII" cells facilitated the apoptosis induced by all-trans retinoic acid (ATRA), which was verified by the greater sub-G1 (apoptotic cells) peak in flow cytometry analysis, more expressions of active caspase-3 and pro-apoptotic protein Bax, as well as less expressions of anti-apoptotic proteins, Bcl-2 and Bcl-X(L). The up regulation of alpha1,3FucT-VII mRNA and cell surface SLe(x) (alpha1,3FucT-VII product) by UV and down regulation of them by ATRA was speculated to be one of the mechanisms that alpha1,3FucT-VII decreased and increased the susceptibility of apoptosis induced by UV and ATRA respectively.

Virus-induced transcriptional activation of host FUT genes associated with neo-expression of Ley in cytomegalovirus-infected and sialyl-Lex in varicella-zoster virus-infected diploid human cells

Cell surface carbohydrate structures including sialyl-Lewis X (sLe(x)) and Lewis Y (Le(y)) are important ligands in normal and malignant tissues. The aim here was to determine the possible influence on the expression of such antigens by two viruses varicella-zoster virus (VZV) and cytomegalovirus (CMV) involved in persistent infections of humans. We found that infection of human diploid fibroblasts with both viruses resulted in transcriptional activation of several fucosyltransferase (FUT) genes that were either dormant or expressed at low levels in uninfected cells. Both viruses induced FUT3, FUT5, and FUT6, encoding alpha1,3- and/or alpha1,4-specific fucosyltransferases. CMV, but not VZV, induced transcription of FUT1 (encoding an alpha1,2-specific fucosyltransferase), FUT7, and FUT9. The changes in transcription of FUT genes were expectedly associated with expression of Le(y) in CMV-infected cells and sLe(x) in the VZV-infected fibroblasts although no expression of these antigens was observed in uninfected cells. One major explanation for this difference between CMV- and VZV-infected cells was that CMV, but not VZV, induced expression of FUT1, necessary for Le(y) expression. The induced carbohydrate antigens in CMV- and VZV-infected cells could be of significance for virus spread and possible escape from immune responses.