Enhancement of the adhesive and spreading potentials of ovarian carcinoma RMG-1 cells due to increased expression of integrin α5β1 with the Lewis Y-structure on transfection of the α1,2-fucosyltransferase gene

HERPUD1 promotes ovarian cancer cell survival by sustaining autophagy and inhibit apoptosis via PI3K/AKT/mTOR and p38 MAPK signaling pathways

HERPUD1 is an important early marker of endoplasmic reticulum stress (ERS) and is involved in the ubiquitination and degradation of several unfolded proteins. However, its role in tumorigenesis is seldom studied, and its role in ovarian cancer is unclear. Lewis y antigen is a tumor-associated sugar antigen that acts as an 'antenna' on the cell surface to receive signals from both inside and outside the cell. We previously reported that Lewis y can promote ovarian cancer by promoting autophagy and inhibiting apoptosis. In this study, we detect the expression of HERPUD1 and Lewis y antigens in 119 different ovarian cancer tissues, determine their relationship with clinicopathological parameters, analyze the correlation between these two proteins, and explore the related cancer-promoting mechanisms through MTT, flow cytometry, western blotting, and bioinformatics. HERPUD1 is highly expressed in ovarian cancer, especially in the early stage, and the expression of HERPUD1 and Lewis y antigen was positively correlated. After overexpression of Lewis y antigen, the expression level of HERPUD1 increased. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathways (KEGG) analysis showed that HERPUD1 and its related genes are enriched in regulating immunity, endoplasmic reticulum stress, ubiquitin-dependent degradation, ERS-induced apoptosis, and other key signaling pathways. We also clarified the HERPUD1 network of kinases, microRNA and transcription factor targets, and the impact of HERPUD1 mutations on prognosis. In addition, HERPUD1 promotes the proliferation of ovarian cancer cells, inhibits apoptosis, affects the cell cycle, promotes the occurrence of autophagy, and inhibits EMT and PI3K/AKT/mTOR and p38MAPK pathways. Overall, HERPUD1, regulated by the expression of tumor-associated protein Lewis y, promotes cell survival in the early stages of tumors, suggesting that HERPUD1 may play an important role in the development of ovarian cancer.

Blood group antigens SLeX, SLeA, and LeY as prognostic markers in endometrial cancer

PURPOSE

Endometrial cancer (EC) is the most common gynecological cancer worldwide. Treatment has been improved in recent years, but, in advanced stages, therapeutical options are still limited. It has been reported that the expression of the blood group antigens Sialyl Lewis X (SLeX), Sialyl Lewis A (SLeA) and Lewis Y (LeY) is associated with prognosis in several tumors. Large studies on endometrial and cervical cancer are still pending.

METHODS

Specimens of 234 patients with EC were immunohistochemically stained with antibodies for SLeX, SLeA and LeY. Expression was correlated to histopathological variables.

RESULTS

High expression of SLeX was correlated to low pT-stage (p = 0.013), low grade (p < 0.001), low FIGO-stage (p = 0.006) and better overall survival rates (OS; p = 0.023). High expression of SLeA was associated with low pT-stage (p = 0.013), low grade (p = 0.001) and better progression-free survival (PFS; p = 0.043). LeY staining was correlated to pN + (p = 0.038), low grade (p = 0.005) and poorer PFS (p = 0.022).

CONCLUSION

This is the first study examining the expression of SLeX, SLeA and LeY in EC, which can serve as additional future prognostic markers. Further studies are necessary to understand the underlying mechanisms. The study was approved by the local ethics committee of the Ludwig-Maximilians University Munich (reference number 19-249).

Human Epididymis Protein 4 and Lewis y Enhance Chemotherapeutic Resistance in Epithelial Ovarian Cancer Through the p38 MAPK Pathway

INTRODUCTION

Ovarian cancer has a high mortality rate due to difficulties in early detection and chemotherapy resistance. Human epididymal protein 4 (HE4) has been adopted as a novel serum biomarker for early ovarian cancer diagnosis, and the presence of Lewis y antigen modifications on HE4 in ovarian cancer cell lines has been detected in previous studies. The aim of this study was to analyze the expression of HE4 and Lewis y antigen in human ovarian cancer in order to find a correlation between them, as well as with the clinical pathological parameters of patients with ovarian cancer.

METHODS

Immunohistochemistry was used to detect the respective expression of these compounds in two patient groups (chemotherapy-resistant and chemotherapy-sensitive) containing a total of 95 patients. Then, a bioinformatic approach was adopted and online large sample databases (TCGA, CCLE, and GTEx; Metascape, Cytoscape) were used to explore the potential mechanisms of action of these compounds.

RESULTS

The results of this study demonstrate that high HE4 and Lewis y expression could be used as markers for chemotherapy resistance and poor prognosis in patients with ovarian cancer. These two expression events were widely correlated in various cancer tissues and are thought to act by activating the p38 mitogen-activated protein kinases (MAPK) pathway and inducing Vascular Endothelial Growth Factor A (VEGFA), Prostaglandin-Endoperoxide Synthase 2 (PTGS2), Early Growth Response 1 (EGR1), and Hypoxia-Inducible Factor 1-Alpha (HIFI1A), thereby promoting malignant biological behavior and resistance in ovarian cancer.

CONCLUSIONS

These findings not only reveal the possible mechanism by which HE4 and Lewis y antigen affect ovarian cancer but also identify a four-gene signature that could be very useful in ovarian cancer detection and/or the development of new targeted therapies.

Fucosyltransferase 4 shapes oncogenic glycoproteome to drive metastasis of lung adenocarcinoma

BACKGROUND

Aberrant fucosylation plays a critical role in lung cancer progression. Nevertheless, the key fucosyltransferase with prognostic significance in lung cancer patients, the enzyme's intracellular targets, and complex molecular mechanisms underlying lung cancer metastasis remain incompletely understood.

METHODS

We performed a large-scale transcriptome-clinical correlation to identify major fucosyltransferases with significant prognostic values. Invasion, migration, cell adhesion assays were performed using lung cancer cells subject to genetic manipulation of FUT4 levels. Genome-wide RNA-seq and immunoprecipitation-mass spectrometry were used to characterize major cellular processes driven by FUT4, as well as profiling its intracellular protein targets. We also performed lung homing and metastasis assays in mouse xenograft models to determine in vivo phenotypes of high FUT4-expressing cancer cells.

FINDINGS

We show that FUT4 is associated with poor overall survival in lung adenocarcinoma patients. High FUT4 expression promotes lung cancer invasion, migration, epithelial-to-mesenchymal transition, and cell adhesion. FUT4-mediated aberrant fucosylation markedly activates multiple cellular processes, including membrane trafficking, cell cycle, and major oncogenic signaling pathways. The effects are independent of receptor tyrosine kinase mutations. Notably, genetic depletion of FUT4 or targeting FUT4-driven pathways diminishes lung colonization and distant metastases of lung cancer cells in mouse xenograft models.

INTERPRETATION

We propose that FUT4 can be a prognostic predictor and therapeutic target in lung cancer metastasis. Our data provide a scientific basis for a potential therapeutic strategy using targeted therapy in a subset of patients with high FUT4-expressing tumors with no targetable mutations.

TGF-β1 fucosylation enhances the autophagy and mitophagy via PI3K/Akt and Ras-Raf-MEK-ERK in ovarian carcinoma

Transforming growth factor-β, a cell secretion factor of the TGF-β superfamily, is involved in the regulation of cell proliferation, differentiation, cytoskeleton formation, migration, invasion and other biological behaviors. Autophagy and mitophagy play an important role in tumor progression by regulating self-digestion, and degradation and reuse of cells and mitochondria. In this study, changes in autophagy and mitophagy processes in ovarian cancer cells under TGF-β1 treatment were detected via Western blot and immunofluorescence, as well as the role of fucosylation modification. Changes in mitochondrial membrane potential in response to TGF-β1 and fucosylation were detected via immunofluorescence. The effects of TGF-β1 and its fucosylation on autophagic flux were further determined by transient transfection of cells with Ad-mRFP-GFP-LC3 adenovirus. TGF-β1 clearly promoted autophagy and mitophagy in ovarian cancer cells. TGF-β1 fucosylation stimulated these regulatory effects on ovarian cancer cells via modulation of PI3K/Akt and Ras-Raf-MEK-ERK pathways through TAK1. Our collective data support the physiological significance of TGF-β1 and provide a novel direction for targeted therapy for ovarian cancer.

Chemotherapy Resistance in Advanced Ovarian Cancer Patients

Ovarian cancer is the seventh most common gynaecologic malignancy seen in women. Majority of the patients with ovarian cancer are diagnosed at the advanced stage making prognosis poor. The standard management of advanced ovarian cancer includes tumour debulking surgery followed by chemotherapy. Various types of chemotherapeutic regimens have been used to treat advanced ovarian cancer, but the most promising and the currently used standard first-line treatment is carboplatin and paclitaxel. Despite improved clinical response and survival to this combination of chemotherapy, numerous patients either undergo relapse or succumb to the disease as a result of chemotherapy resistance. To understand this phenomenon at a cellular level, various macromolecules such as DNA, messenger RNA and proteins have been developed as biomarkers for chemotherapy response. This review comprehensively summarizes the problem that pertains to chemotherapy resistance in advanced ovarian cancer and provides a good overview of the various biomarkers that have been developed in this field.

Ascites from Ovarian Cancer Induces Novel Fucosylated Proteins

Ovarian cancer is considered to be the most lethal type of gynecological cancer. During the advanced stages of ovarian cancer, an accumulation of ascites is observed. Fucosylation has been classified as an abnormal post-translational modification that is present in many diseases, including ovarian cancer. Ovarian cancer cells that are cultured with ascites stimulation change their morphology; concomitantly, the fucosylation process is altered. However, it is not known which fucosylated proteins are modified. The goal of this work was to identify the differentially fucosylated proteins that are expressed by ovarian cancer cell lines that are cultured with ovarian cancer patients' ascites. Aleuria aurantia lectin was used to detect fucosylation, and some changes were observed, especially in the cell membrane. Affinity chromatography and mass spectrometry (MALDI-TOF) were used to identify 6 fucosylated proteins. Four proteins (Intermediate filament family orphan 1 [IFFO1], PHD finger protein 20-like protein 1 [PHF20L1], immunoglobulin gamma 1 heavy chain variable region partial [IGHV1-2], and Zinc finger protein 224 [ZNF224]) were obtained from cell cultures stimulated with ascites, and the other two proteins (Peregrin [BRPF1] and Dystrobrevin alpha [DTNA]) were obtained under normal culture conditions. The fucosylated state of some of these proteins was further analyzed. The experimental results show that the ascites of ovarian cancer patients modulated the fucosylation process. The PHD finger protein 20-like protein 1, Zinc finger protein 224 and Peregrin proteins colocalize with fucosylation at different levels.

Co‑expression of Lewis y antigen and CD147 in epithelial ovarian cancer is correlated with malignant progression and poor prognosis

CD147 is a highly glycosylated transmembrane protein expressed on the surface of tumor cells. In the present study, the expression and clinical significance of the Lewis y antigen and CD147 in epithelial ovarian cancer (EOC) were analyzed, and the function and correlation in between the expression of Lewis y and CD147 were evaluated using immunohistochemical staining, reverse transcription‑quantitative polymerase chain reaction analysis, immunocytochemical staining, immunoprecipitation and western blotting. The results showed that the expression of CD147 was higher in EOC tissues and correlated with a higher tumor burden. Lewis y and CD147 exhibited similar expression patterns and their expression was positively correlated. The results of the immunofluorescence and immunoprecipitation experiments showed that Lewis y and CD147 colocalized in the cell membrane and cytoplasm. Lewis y antigen, but not Lewis x or sialyl Lewis x, was predominantly expressed in the highly glycosylated form of CD147. These changes occurred at the post‑transcriptional level. As an important component of CD147, Lewis y promoted CD147‑mediated cell adhesion and the expression of matrix metalloproteinase 2. In conclusion, Lewis y antigen and CD147 were significantly upregulated in ovarian tumors, and the altered expression of Lewis y may cause changes in CD147. The two molecules are associated with carcinogenesis and the development of ovarian cancer, and Lewis y antigen is a component of the CD147 structure.

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.

Biological functions of fucose in mammals

Fucose is a 6-deoxy hexose in the l-configuration found in a large variety of different organisms. In mammals, fucose is incorporated into N-glycans, O-glycans and glycolipids by 13 fucosyltransferases, all of which utilize the nucleotide-charged form, GDP-fucose, to modify targets. Three of the fucosyltransferases, FUT8, FUT12/POFUT1 and FUT13/POFUT2, are essential for proper development in mice. Fucose modifications have also been implicated in many other biological functions including immunity and cancer. Congenital mutations of a Golgi apparatus localized GDP-fucose transporter causes leukocyte adhesion deficiency type II, which results in severe developmental and immune deficiencies, highlighting the important role fucose plays in these processes. Additionally, changes in levels of fucosylated proteins have proven as useful tools for determining cancer diagnosis and prognosis. Chemically modified fucose analogs can be used to alter many of these fucose dependent processes or as tools to better understand them. In this review, we summarize the known roles of fucose in mammalian physiology and pathophysiology. Additionally, we discuss recent therapeutic advances for cancer and other diseases that are a direct result of our improved understanding of the role that fucose plays in these systems.

Fucosylated Antigens in Cancer: An Alliance toward Tumor Progression, Metastasis, and Resistance to Chemotherapy

Aberrant glycosylation of tumor cells is recognized as a universal hallmark of cancer pathogenesis. Overexpression of fucosylated epitopes, such as type I (H1, Lewis^a, Lewis^b, and sialyl Lewis^a) and type II (H2, Lewis^x, Lewis^y, and sialyl Lewis^x) Lewis antigens, frequently occurs on the cancer cell surface and is mainly attributed to upregulated expression of pertinent fucosyltransferases (FUTs). Nevertheless, the impact of fucose-containing moieties on tumor cell biology is not fully elucidated yet. Here, we review the relevance of tumor-overexpressed FUTs and their respective synthesized Lewis determinants in critical aspects associated with cancer progression, such as increased cell survival and proliferation, tissue invasion and metastasis, epithelial to mesenchymal transition, epithelial and immune cell interaction, angiogenesis, multidrug resistance, and cancer stemness. Furthermore, we discuss the potential use of enhanced levels of fucosylation as glycan biomarkers for early prognosis, diagnosis, and disease monitoring in cancer patients.

Lewis y antigen promotes p27 degradation by regulating ubiquitin-proteasome activity

As a tumor-associated carbohydrate antigen, elevated expression of Lewis y promotes the malignant behaviors of tumor cells. Although our preliminary study showed that the increased expression of Lewis y antigen decreased the expression of cell cycle inhibitor protein p27, the relevant mechanism remains unclear. Autophagy and the ubiquitin-proteasome system are two main ways of intracellular protein degradation, whose abnormal activities are closely associated with progression of malignant tumors. In our present study, we constructed two stable transfected cell lines with high expression of Lewis y antigen, named CAOV3-FUT1 and SKOV3-FUT1. We showed that the proportion of cells at S phase was significantly increased after FUT1 transfection, whereas p27 protein was obviously decreased. The autophagy activity, the levels of ubiquitination, and chymotrypsin-like protease activity were increased remarkably in the transfected cells. Interestingly, Lewis y antigen promoted the degradation of p27 by increasing ubiquitin-proteasome activity. In the vivo studies, Lewis y antigen improved the tumorigenic ability of ovarian cancer cells in nude mice and reduced the expression of p27. These findings suggested that Lewis y antigen activated both the autophagy and ubiquitin-proteasome activity and promoted the degradation of p27 through the ubiquitin-proteasome pathway.

Targeting tumor-associated carbohydrate antigens: a phase I study of a carbohydrate mimetic-peptide vaccine in stage IV breast cancer subjects

Tumor-associated carbohydrate antigens (TACAs) support cell survival that could be interrupted by anti-TACA antibodies. Among TACAs that mediate cell survival signals are the neolactoseries antigen Lewis Y (LeY) and the ganglioside GD2. To induce sustained immunity against both LeY and GD2, we developed a carbohydrate mimicking peptide (CMP) as a surrogate pan-immunogen that mimics both. This CMP, referred to as P10s, is the N-terminal half of a peptide vaccine named P10s-PADRE, the C-terminal half of which (PADRE) is a Pan-T-cell epitope. A Phase I dose-escalation trial of P10s-PADRE plus adjuvant MONTANIDE™ ISA 51 VG was conducted in subjects with metastatic breast cancer to test 300 and 500 μg/injection in two cohorts of 3 subjects each. Doses of the P10s-PADRE vaccine were administered to research participants subcutaneously on weeks 1, 2, 3, 7 and 19. Antibody responses to P10s, GD2, and LeY were measured by ELISA. The P10s-PADRE vaccine induced antibodies specifically reactive with P10s, LeY and GD2 in all 6 subjects. Serum antibodies displayed Caspase-3-dependent apoptotic functionality against LeY or GD2 expressing breast cancer cell lines. Immunization with the P10s-PADRE vaccine was well-tolerated and induced functional antibodies, and the data suggest potential clinical benefit.

High expressions of BCL6 and Lewis y antigen are correlated with high tumor burden and poor prognosis in epithelial ovarian cancer

Aberrant regulation of BCL6 plays crucial oncogenic roles in various malignant tumors; howbeit, the function of BCL6 in tumorigenesis of ovarian cancer remains unclear. The aim of this study is to investigate the role of BCL6 in ovarian cancer. The methods of immunohistochemical staining, quantitative real-time polymerase chain reaction, immunocytochemical staining, and gene expression profile enrichment analysis were performed to identify the possible role of BCL6 in ovarian cancer. We observed that the expression of BCL6 was significantly higher in ovarian cancer tissues and correlated with higher tumor burden including advanced International Federation of Gynecology and Obstetrics stages, poor differentiation, Type II ovarian cancer, the presence of >1 cm residual tumor size, and appearance of recurrence or death (all p < 0.05). The expression patterns of Lewis y were similar to these of BCL6. Multivariate Cox analysis demonstrated that advanced International Federation of Gynecology and Obstetrics stage, lymph node metastasis, residual tumor size >1 cm, as well as high expressions of BCL6 and Lewis y antigen were independent factors of worse progression-free survival and overall survival (all p < 0.05). There was a positive correlation of the expressions of BCL6 and Lewis y antigen. The associated genes with BCL6 in response to Lewis y antigen were identified, including four upregulated genes ( SOCS3, STAT1, PPARG, and GADD45A) and three downregulated genes ( ACAN, E2F3, and ZBTB7B). In conclusion, the high expressions of BCL6 and Lewis y antigen are associated with development, high tumor burden, and worse prognosis of ovarian cancer and targeting BCL6 could be a novel therapeutic strategy for ovarian cancer treatment.

The translational blocking of α5 and α6 integrin subunits affects migration and invasion, and increases sensitivity to carboplatin of SKOV-3 ovarian cancer cell line

Epithelial ovarian cancer is the most lethal gynecologic malignancy. Integrins, overexpressed in cancer, are involved in various processes that favor the development of the disease. This study focused on determining the degree of involvement of α5, α6 and β3 integrin subunits in the establishment/development of epithelial ovarian cancer (EOC), such as proliferation, migration, invasion, and response to carboplatin. The translation of the α5, α6 and β3 integrins was blocked using morpholines, generating morphant cells for these proteins, which were corroborated by immunofluorescence assays. WST-1 proliferation assay showed that silencing of α5, α6, and β3 integrins does not affect the survival of morphants. Wound healing and transwell chamber assays showed that blocking α5 and α6 integrins decrease, in lesser and greater level respectively, the migratory and the invasive capacity of SKOV-3 cells. Finally, blocking α5 and α6 integrins partially sensitized the cells response to carboplatin, while blocking integrin β3 generated resistance to this drug. Statistical analyses were performed with the GraphPad Prism 5.0 software employing one way and two-way ANOVA tests; data are shown as average±SD. Results suggest that α5 and α6 integrins could become good candidates for chemotherapy targets in EOC.

Gene expression profile analysis in response to α1,2-fucosyl transferase (FUT1) gene transfection in epithelial ovarian carcinoma cells

The aim of this study was to identify differentially expressed genes (DEGs) in response to α1,2-fucosyl transferase (FUT1) gene transfection in epithelial ovarian cancer cells. Human whole-genome oligonucleotide microarrays were used to determine whether gene expression profile may differentiate the epithelial ovarian cell line Caov-3 transfected with FUT1 from the empty plasmid-transfected cells. Quantitative real-time PCR and immunohistochemical staining validated the microarray results. Gene expression profile identified 215 DEGs according to the selection criteria, in which 122 genes were upregulated and 93 genes were downregulated. Gene Ontology (GO) and canonical pathway enrichment analysis were applied, and we found that these DEGs are involved in BioCarta mammalian target of rapamycin (mTOR) pathway, BioCarta eukaryotic translation initiation factor 4 (EIF4) pathway, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in cancer. Interaction network analysis predicted genes participating in the regulatory connection. Highly differential expression of TRIM46, PCF11, BCL6, PTEN, and FUT1 genes was validated by quantitative real-time PCR in two cell line samples. Finally, BCL6 and Lewis Y antigen were validated at the protein level by immunohistochemistry in 103 paraffin-embedded ovarian cancer tissues. The identification of genes in response to FUT1 may provide a theoretical basis for the investigations of the molecular mechanism of ovarian cancer.

On the trail of the glycan codes stored in cancer-related cell adhesion proteins

Changes in the profile of protein glycosylation are a hallmark of ongoing neoplastic transformation. A unique set of tumor-associated carbohydrate antigens expressed on the surface of malignant cells may serve as powerful diagnostic and therapeutic targets. Cell-surface proteins with altered glycosylation affect the growth, proliferation and survival of those cells, and contribute to their acquisition of the ability to migrate and invade. They may also facilitate tumor-induced immunosuppression and the formation of distant metastases. Deciphering the information encoded in these particular glycan portions of glycoconjugates may shed light on the mechanisms of cancer progression and metastasis. A majority of the related review papers have focused on overall changes in the patterns of cell-surface glycans in various cancers, without pinpointing the molecular carriers of these glycan structures. The present review highlights the ways in which particular tumor-associated glycan(s) coupled with a given membrane-bound protein influence neoplastic cell behavior during the development and progression of cancer. We focus on altered glycosylated cell-adhesion molecules belonging to the cadherin, integrin and immunoglobulin-like superfamilies, examined in the context of molecular interactions.

Lewis y enhances CAM-DR in ovarian cancer cells by activating the FAK signaling pathway and upregulating Bcl-2/Bcl-XL expression

Oligosaccharides on the surface of adhesion molecules may contribute to the process of CAM-DR. To investigate the role of the Lewis y antigen in this process, we established a cell adhesion model mediated by the integrin α5β1-FN interaction in the ovarian cancer cell line, RMG-1-hFUT, which highly expresses Lewis y by transfection with α1,2-fucosyltransferase into RMG-1 cells. Our results indicate that the rates of carboplatin-induced apoptosis and necrosis are reduced in FN-adhered tumor cells, and carboplatin resistance is significantly decreased in the presence of anti-Lewis y antibody. CAM-DR in tumor cells has been correlated with elevated expression of the nuclear anti-apoptotic proteins Bcl-2 and Bcl-XL. Lewis y promotes the expression of the Bcl-2 and Bcl-XL genes by activating the focal adhesion kinase signaling pathway and accelerating their transcription. Thus, Lewis y leads to inhibition of apoptosis and enhancement of CAM-DR by activation of the FAK signaling pathway and upregulation of Bcl-2/Bcl-XL expression in ovarian cancer cell lines.

Lewisy promotes migration of oral cancer cells by glycosylation of epidermal growth factor receptor

Aberrant glycosylation changes normal cellular functions and represents a specific hallmark of cancer. Lewis^y (Le^y) carbohydrate upregulation has been reported in a variety of cancers, including oral squamous cell carcinoma (OSCC). A high level of Le^y expression is related to poor prognosis of patients with oral cancer. However, it is unclear how Le^y mediates oral cancer progression. In this study, the role of Le^y in OSCC was explored. Our data showed that Le^y was upregulated in HSC-3 and OC-2 OSCC cell lines. Particularly, glycosylation of epidermal growth factor receptor (EGFR) with Le^y was found in OC-2 cells, and this modification was absent upon inhibition of Le^y synthesis. The absence of Le^y glycosylation of EGFR weakened phosphorylation of AKT and ERK in response to epidermal growth factor (EGF). Additionally, EGF-triggered cell migration was reduced, but cell proliferation was not affected. Le^y modification stabilized EGFR upon ligand activation. Conversely, absence of Le^y glycosylation accelerated EGFR degradation. In summary, these results indicate that increased expression of Le^y in OSCC cells is able to promote cell migration by modifying EGFR which in turn stabilizes EGFR expression and downstream signaling. Targeting Le^y on EGFR could have a potential therapeutic effect on oral cancer.

Gene expression profile analysis identifies metastasis and chemoresistance-associated genes in epithelial ovarian carcinoma cells

The purpose of this study was to identify genes that associated with higher ability of metastasis and chemotherapic resistance in epithelial ovarian carcinoma (EOC) cells. An oligonucleotide microarray with probe sets complementary to 41,000⁺ unique human genes and transcripts was used to determine whether gene expression profile may differentiate three epithelial ovarian cell lines (RMG-I-C, COC1 and HO8910) from their sub-lines (RMG-I-H, COCI/DDP and HO8910/PM) with higher ability of metastasis and chemotherapic resistance. Quantitative real-time PCR and immunohistochemical staining validated the microarray results. Hierarchic cluster analysis of gene expression identified 49 genes that exhibited ≥2.0-fold change and P value ≤0.05. Highly differential expression of GCET2, NLRP4, FOXP1 and SNX29 genes was validated by quantitative PCR in all cell line samples. Finally, FOXP1 was validated at the protein level by immunohistochemistry in paraffin embedded ovarian tissues (i.e., for metastasis, 15 primary EOC and 10 omental metastasis [OM]; for chemoresistance, 13 sensitive and 13 resistant EOC). The identification of higher ability of metastasis and chemotherapic resistance-associated genes may provide a foundation for the development of new type-specific diagnostic strategies and treatment for metastasis and chemotherapic resistance in epithelial ovarian cancer.

c-Jun transcriptionally regulates alpha 1, 2-fucosyltransferase 1 (FUT1) in ovarian cancer

Alpha 1, 2-fucosyltransferase (FUT 1/2) is a rate-limiting enzyme that catalyzes the synthesis of Lewis y, a cell membrane-associated carbohydrate antigen. In human ovarian cancer, the upregulated expression of FUT1 and Lewis y is associated with advanced pathological stages and involved in cell proliferation, migration and invasion. However, the mechanism underlying the upregulation of FUT1 is largely unknown. Here, we identify an AP-1 binding site in FUT1 promoter in ovarian cancer cells. c-Jun promotes FUT1 expression, thereby enhancing Lewis y biosynthesis in various ovarian cancer cell lines. Moreover, EMSA, luciferase activity and ChIP assays demonstrate c-Jun directly interacts with FUT1 promoter. Furthermore, FUT1 mediates c-Jun-induced cell proliferation in ovarian cancer cells. In human ovarian cancer samples, c-Jun overexpression is linked to malignant degree and positively correlated to FUT1 and Lewis y expression. Taken together, c-Jun could transcriptionally modulate FUT1 expression in ovarian cancer, implicating the potential application of c-Jun inhibitors for human ovarian cancer therapy.

The expression of annexin II and Lewis y antigen in ovarian epithelial tumors and the correlation between them

The main aim of this study was to explore the molecular structural relationship between annexin II (ANXA2) and Lewis y antigen by determining their expression patterns and clinical significance in ovarian epithelial carcinoma. The structural relationship between ANXA2 and Lewis y antigen was examined using immunoprecipitation and confocal laser scanning microscopy in two ovarian caner cell lines ES-2 and CaoV-3. We also constracted the stably transfected cell lines with low ANXA2 gene expression in order to detect the expression level between ANXA2 and Lewis y. ANXA2 and Lewis y were detected in tissues from malignant, borderline, benign, and normal ovarian tissues using immunohistochemical analysis. ANXA2 and Lewis y were present in both two ovarian cancer cells and ANXA2 contained Lewis y antigen. Moreover, expression of Lewis y antigen in ANXA2 from cell after transfection was higher than that before. Our immunohistochemistry data revealed significantly higher positive expression rates of ANXA2 in malignant ovarian tissues, compared to benign tumor and normal tissue, similar to Lewis y antigen levels in ovarian cancer. Notably, tissues displaying marked expression of ANXA2 simultaneously expressed high levels of Lewis y antigen. A linear correlation between the expression patterns of ANXA2 and Lewis y antigen was evident. Consistently, double-labeling immunofluorescence experiments illustrated co-localization of ANXA2 and Lewis y antigen within the same area. In conclusions, ANXA2 contains Lewis y antigen. Our results further demonstrate a close correlation between the expression levels of the two antigens, which are significantly high in ovarian cancer.

Overexpression of Lewis y antigen promotes human epididymis protein 4-mediated invasion and metastasis of ovarian cancer cells

To study Human epididymis protein 4 (HE4) surface fucosylation and to determine the effects and significance of Lewis y antigen on HE4-mediated invasion and metastasis of ovarian cancer cells, we investigated four types of ovarian cancer cells and found that six fucosylated antigens (Lewis y, Lewis x, Lewis a, Lewis b, sLewis a, and sLewis x) were identified on HE4 in ovarian cancer cells. Moreover, modification of the type II sugar chain (Lewis y, Lewis x, and sLewis x) was significantly higher than the type I sugar chain (Lewis a, Lewis b, sLewis a) of the lactose series. To confirm the effects of Lewis y antigen on HE4-mediated invasion and metastasis of ovarian cancer cells, the CaoV-3 cells with high Lewis y antigen on the HE4 surface and ES-2 cells, with high Lewis x antigen but low Lewis y antigen, were investigated. We found that the expression levels of HE4 and Lewis y increased in both cell lines while the level of Lewis x didn't have any change after transfection. Furthermore, the high expression of Lewis y antigen significantly enhanced the HE4-mediated invasion and metastasis of ovarian cancer cells. The invasion and metastasis capacities were significantly decreased after Lewis y antibody blocking. This study demonstrates that overexpression of the Lewis y antigen on HE4 promotes ovarian cancer cell invasion and metastasis, which is likely to be used as a target for the clinical treatment of ovarian cancer.

Calreticulin activates β1 integrin via fucosylation by fucosyltransferase 1 in J82 human bladder cancer cells

Fucosylation regulates various pathological events in cells. We reported that different levels of CRT (calreticulin) affect the cell adhesion and metastasis of bladder cancer. However, the precise mechanism of tumour metastasis regulated by CRT remains unclear. Using a DNA array, we identified FUT1 (fucosyltransferase 1) as a gene regulated by CRT expression levels. CRT regulated cell adhesion through α1,2-linked fucosylation of β1 integrin and this modification was catalysed by FUT1. To clarify the roles for FUT1 in bladder cancer, we transfected the human FUT1 gene into CRT-RNAi stable cell lines. FUT1 overexpression in CRT-RNAi cells resulted in increased levels of β1 integrin fucosylation and rescued cell adhesion to type-I collagen. Treatment with UEA-1 (Ulex europaeus agglutinin-1), a lectin that recognizes FUT1-modified glycosylation structures, did not affect cell adhesion. In contrast, a FUT1-specific fucosidase diminished the activation of β1 integrin. These results indicated that α1,2-fucosylation of β1 integrin was not involved in integrin-collagen interaction, but promoted β1 integrin activation. Moreover, we demonstrated that CRT regulated FUT1 mRNA degradation at the 3'-UTR. In conclusion, the results of the present study suggest that CRT stabilized FUT1 mRNA, thereby leading to an increase in fucosylation of β1 integrin. Furthermore, increased fucosylation levels activate β1 integrin, rather than directly modifying the integrin-binding sites.

Co-expression of Lewis y antigen with human epididymis protein 4 in ovarian epithelial carcinoma

Objective

The main aims of this study were to explore the molecular structural relationship between Human epididymis protein 4 (HE4) and Lewis y antigen by determining their expression patterns and clinical significance in ovarian epithelial carcinoma.

Methods

The structural relationship between HE4 and Lewis y antigen was examined using immunoprecipitation and confocal laser scanning microscopy. HE4 and Lewis y were detected in tissues from malignant (53 cases), borderline (27 cases), benign (15 cases) and normal ovarian tissues (15 cases) using immunohistochemical analysis.

Results

HE4 was present in ovarian cancer, benign tumor tissues, ovarian carcinoma cells, and culture medium, and contained Lewis y antigen. Moreover, expression of Lewis y antigen in HE4 from ovarian cancer was higher than that from benign tumor (P<0.05). HE4 possibly exists as two protein isoforms, both containing Lewis y antigen. Our immunohistochemistry data revealed significantly higher positive expression rates of HE4 in malignant ovarian tissues, compared to benign tumor and normal tissue (P<0.05), similar to Lewis y antigen levels in ovarian cancer (P<0.05). Notably, tissues displaying marked expression of HE4 simultaneously expressed high levels of Lewis y antigen. A linear correlation between the expression patterns of HE4 and Lewis y antigen was evident. Consistently, double-labeling immunofluorescence experiments illustrated co-localization of HE4 and Lewis y antigen within the same area.

Conclusions

HE4 contains Lewis y antigen. Our results further demonstrate a close correlation between the expression levels of the two antigens, which are significantly high in ovarian cancer.

Expression of Lewis y antigen and integrin αv, β3 in ovarian cancer and their relationship with chemotherapeutic drug resistance

OBJECTIVE

This study investigates the expression of Lewis y antigen, integrin αv, β3 in epithelial ovarian cancer tissues. We further evaluate the relationship between their expression and chemotherapy resistance of ovarian cancer and its possible clinical significance.

METHODS

Tissues of 92 patients with ovarian cancer meeting the inclusion criteria with complete follow-up data were enrolled and divided into chemotherapy resistant group and sensitive group. The expression and relationship of Lewis y antigen and integrin αv, β3 are assessed in paraffin sections using immunohistochemistry and double-labeling immunofluorescence method. Multivariate logistic regression analysis was used to investigate the relationship between age, clinical stage, differentiation, histologic subtype, Lewis y antigen and integrin αv, β3 expression in ovarian cancer patients.

RESULTS

The expression rates of Lewis y antigen and integrin αv in the resistant group, significantly higher than the rates found in the sensitive group (p <0.05). Multivariate analysis showed that the expression of Lewis y antigen, integrin αv and ovarian cancer's clinical stage were independent, drug resistance-related risk factors. The expression levels of Lewis y antigen and integrin αv, β3 were positively correlated with each other.

CONCLUSIONS

A close correlation between Lewis y antigen, integrin αv, β3 and ovarian cancer was observed. Lewis y antigen can influence the biological behavior of a tumor cell as an important composition of integrin αv, β3 by some signal pathway. And the expression of Lewis y antigen, integrin αv and ovarian cancer's clinical stage are both independent, drug resistance-related risk factors.

Chemoresistance is associated with MUC1 and Lewis y antigen expression in ovarian epithelial cancers

Objective

The aim of this study was to analyze the correlation and clinical significance between the expression of Mucin-1 (MUC1) and the Lewis y antigen with chemoresistance in ovarian epithelial cancers.

Methods

Ovarian cancer patients (n = 92) treated at our hospital from May 2005 to July 2009 were divided, according to their treatment and follow-up outcomes, into a resistant group (n = 37) or sensitive group (n = 55). The expression of MUC1 and Lewis y antigen in ovarian cancer tissues was detected using immunohistochemistry and correlated with chemoresistance.

Results

The positive rates of MUC1 and Lewis y antigen in the resistant group were both 91.89%, significantly higher than their positive rates in the sensitive group (65.45% and 69.09%, respectively, and both p < 0.05). MUC1 or Lewis y expression and the pathological stage of the tissue were independent risk factors for chemoresistance (all p < 0.05).

Conclusion

The increased expression of MUC1 and the Lewis y antigen is a significant risk factor for chemoresistance in patients with ovarian epithelial cancer.

High expression of Lewis y antigen and CD44 is correlated with resistance to chemotherapy in epithelial ovarian cancers

Objectives

To measure Lewis y antigen and CD44 antigen expression in epithelial ovarian carcinoma and to correlate the levels of these antigens with clinical response to chemotherapy.

Methods

The study cases included 34 cases of ovarian carcinoma with resistance to chemotherapeutic drugs, 6 partially drug-sensitive cases, and 52 drug-sensitive cases (92 total).

Results

The rates of expression of Lewis y antigen and CD44 antigen were significantly greater in the drug-resistant group than that in the partially-sensitive or sensitive groups. Surgical stage, residual tumor size and expression of CD44 and Lewis y antigen in ovarian carcinoma tissues were independent risk factors for chemotherapeutic drug resistance.

Conclusions

Over-expression of Lewis y and CD44 antigen are strong risk factors for chemotherapeutic drug resistance in ovarian carcinoma patients.

Elevated levels of Lewis y and integrin α5β1 correlate with chemotherapeutic drug resistance in epithelial ovarian carcinoma

Objective

To measure Lewis y and integrin α₅β₁ expression in epithelial ovarian carcinoma and to correlate the levels of these molecules with ovarian carcinoma chemotherapy and prognosis.

Methods

The study population included 34 ovarian carcinoma patients with chemotherapeutic drug-resistance, six partially drug-sensitive cases, and 52 drug-sensitive cases (92 total). Immunochemistry was used to determine expression of Lewis y antigen and integrin α₅β₁ in ovarian carcinoma tissues, and correlation of these molecules with chemotherapy resistance was further investigated, Multi-factor logistic regression analysis was applied to investigate: age, surgical stage, grade, subtype of patient cases, metastasis of lymph nodes, residual tumor size, expression levels of Lewis y antigen and integrin α₅β₁ correlation with ovarian carcinoma chemotherapy resistance.

Results

The expression rates of Lewis y antigen and integrins α₅ and β₁ were significantly greater in the drug-resistant group (91.17%, 85.29%, 88.24%) than the partially sensitive (50.00%, 33.33%, 50.00%) or sensitive groups (61.54%, 57.69%, 55.77%). Binary logistic regression analysis revealed that surgical stage, residual tumor size, and expression of integrin α₅ and Lewis y in ovarian carcinoma tissues were independent risk factors for chemotherapeutic drug resistance.

Conclusions

Overexpression of Lewis y and integrin α₅ are strong risk factors for chemotherapeutic drug resistance in ovarian carcinoma patients.

An easily accessible sulfated saccharide mimetic inhibits in vitro human tumor cell adhesion and angiogenesis of vascular endothelial cells

Oligosaccharides aberrantly expressed on tumor cells influence processes such as cell adhesion and modulation of the cell’s microenvironment resulting in an increased malignancy. Schmidt’s imidate strategy offers an effective method to synthesize libraries of various oligosaccharide mimetics. With the aim to perturb interactions of tumor cells with extracellular matrix proteins and host cells, molecules with 3,4-bis(hydroxymethyl)furan as core structure were synthesized and screened in biological assays for their abilities to interfere in cell adhesion and other steps of the metastatic cascade, such as tumor-induced angiogenesis.

The most active compound, (4-{[(β-D-galactopyranosyl)oxy]methyl}furan-3-yl)methyl hydrogen sulfate (GSF), inhibited the activation of matrix-metalloproteinase-2 (MMP-2) as well as migration of the human melanoma cells of the lines WM-115 and WM-266-4 in a two-dimensional migration assay. GSF inhibited completely the adhesion of WM-115 cells to the extracellular matrix (ECM) proteins, fibrinogen and fibronectin.

In an in vitro angiogenesis assay with human endothelial cells, GSF very effectively inhibited endothelial tubule formation and sprouting of blood vessels, as well as the adhesion of endothelial cells to ECM proteins. GSF was not cytotoxic at biologically active concentrations; neither were 3,4-bis{[(β-D-galactopyranosyl)oxy]methyl}furan (BGF) nor methyl β-D-galactopyranoside nor 3,4-bis(hydroxymethyl)furan, which were used as controls, eliciting comparable biological activity. In silico modeling experiments, in which binding of GSF to the extracellular domain of the integrin α_vβ₃ was determined, revealed specific docking of GSF to the same binding site as the natural peptidic ligands of this integrin. The sulfate in the molecule coordinated with one manganese ion in the binding site.

These studies show that this chemically easily accessible molecule GSF, synthesized in three steps from 3,4-bis(hydroxymethyl)furan and benzoylated galactose imidate, is nontoxic and antagonizes cell physiological processes in vitro that are important for the dissemination and growth of tumor cells in vivo.

Macrophages regulate expression of α1,2-fucosyltransferase genes in human endometrial epithelial cells

The epithelial cell surface of the endometrium undergoes substantial biochemical changes to allow embryo attachment and implantation in early pregnancy. We hypothesized that tissue macrophages influence these events to promote uterine receptivity. To investigate the role of macrophages in regulating epithelial cell expression of genes linked to glycan-mediated embryo adhesion, Ishikawa, RL95-2 and HEC1A endometrial epithelial cells were cultured alone or with unactivated or lipopolysaccharide-activated monocytic U937 cells, separated using transwell inserts. Expression of mRNAs encoding two α1,2-fucosyltransferases (FUT1, FUT2) was increased in all three epithelial cell lines following co-culture with U937 cells, and was associated with increased fucosylation of cell surface glycoproteins detected using lectins from Ulex europaeus (UEA-1) and Dolichos biflorus (DBA). FUT1 induction by U937 cells also occurred in primary endometrial epithelial cells collected in luteal but not proliferative phase. Activation of the interleukin-6 (IL6)/leukemia inhibitory factor (LIF) cytokine signaling pathway with phosphorylation of STAT3 and elevated SOCS3 mRNA expression was evident in epithelial cells stimulated by U937 co-culture. Several recombinant macrophage-secreted cytokines exerted stimulatory or inhibitory effects on FUT1 and FUT2 mRNA expression, and the macrophage-derived cytokine LIF partially replicated the effects of U937 cells on both FUT1 and FUT2 expression and UEA-1 and DBA lectin reactivity in Ishikawa cells. These results suggest that macrophage-derived factors including LIF might facilitate development of an implantation-receptive endometrium by regulating surface glycan structures in epithelial cells. Abnormal phenotypes or altered abundance of uterine macrophages could contribute to the pathophysiology of primary unexplained infertility in women.

Human epididymis protein 4 (HE4) plays a key role in ovarian cancer cell adhesion and motility

Human epididymis protein 4 (HE4) is a novel and specific biomarker for epithelial ovarian cancer (EOC). We previously demonstrated that serum HE4 levels were significantly elevated in the majority of EOC patients but not in subjects with benign disease or healthy controls. However, the precise mechanism of HE4 protein function is unknown. In this study, we generated HE4-overexpressing SKOV3 cells and found that stably transduced cells promoted cell adhesion and migration. Knockdown of HE4 expression was achieved by stable transfection of SKOV3 cells with a construct encoding a short hairpin DNA directed against the HE4 gene. Correspondingly, the proliferation and spreading ability of HE4-expressed cells were inhibited by HE4 suppression. Mechanistically, impaired EGFR and Erk1/2 phosphorylation were observed in cells with HE4 knockdown. The phosphorylation was restored when the knockdown cells were cultured in conditioned medium containing HE4. Moreover, in vivo tumorigenicity showed that HE4 suppression markedly inhibited the growth of tumors. This suggests that expression of HE4 is associated with cancer cell adhesion, migration and tumor growth, which can be related to its effects on the EGFR-MAPK signaling pathway. Our results provide evidence of the cellular and molecular mechanisms that may underlie the motility-promoting role of HE4 in EOC progression. The role of HE4 as a target for gene-based therapy might be considered in future studies.

Lewis y regulate cell cycle related factors in ovarian carcinoma cell RMG-I in vitro via ERK and Akt signaling pathways

Objective

To investigate the effect of Lewis y overexpression on the expression of proliferation-related factors in ovarian cancer cells.

Methods

mRNA levels of cyclins, CDKs, and CKIs were measured in cells before and after transfection with the α1,2-fucosyltransferase gene by real-time PCR, and protein levels of cyclins, CDKs and CKIs were determined in cells before and after gene transfection by Western blot.

Results

Lewis y overexpression led to an increase in both mRNA and protein expression levels of cyclin A, cyclin D1 and cyclin E in ovarian cancer cells, decrease in both mRNA and protein expression levels of p16 and p21, and decrease of p27 at only the protein expression level without change in its mRNA level. There were no differences in proteins and the mRNA levels of CDK2, CDK4 and CDK6 before and after gene transfection. Anti-Lewis y antibody, ERK and PI3K pathway inhibitors PD98059 and LY294002 reduced the difference in cyclin and CKI expression caused by Lewis y overexpression.

Conclusion

Lewis y regulates the expression of cell cycle-related factors through ERK/MAPK and PI3K/Akt signaling pathways to promote cell proliferation.

Study on the expression and clinical significances of lewis y antigen and integrin αv, β3 in epithelial ovarian tumors

OBJECTIVE

To detect the expression and clinical significances of Lewis y antigen and integrin αv, β3 in epithelial ovarian tumors, and to explore the expression correlation between Lewis y antigen and integrin αv, β3.

METHODS

Immunohistochemical staining was performed in 95 cases of epithelial ovarian cancer, 37 cases of borderline tumors, 20 cases of benign tumors, and 20 cases of normal ovarian tissue, for the detection of Lewis y antigen and integrin αv, β3 expressions, and to analyze the relationship between Lewis y antigen and integrin, and the relationship between clinical and pathological parameters of ovarian cancer. In addition, immunofluorescence double labeling was utilized to detect the expression correlation between Lewis y antigen and integrin αv, β3 in ovarian cancer.

RESULTS

In epithelial ovarian tumors, the expression rate of Lewis y antigen was 81.05%, significantly higher than that of borderline (51.53%) (P < 0.05) and benign (25%) (P < 0.01) tumors, and normal ovarian tissues (0) (P < 0.01). The expression rate of integrin αv, β3 in malignant epithelial ovarian tumors was 78.95% and 82.11%, respectively, significantly higher than that of the borderline (45.94%, 40.54%) (both P < 0.05), benign group (10.00%, 15.00%) (both P < 0.01) and normal ovary group (5%, 15%) (both P < 0.01).

CONCLUSIONS

Lewis y and integrins αv, β3 are relevant to pelvic and abdominal diffusion and metastasis of ovarian cancer cells, suggesting that these two molecules mediate a boosting function for tumor metastasis.

Enhancive effects of Lewis y antigen on CD44-mediated adhesion and spreading of human ovarian cancer cell line RMG-I

Background

This study aimed to investigate the molecular structural relationship between cell adhesive molecule CD44 and Lewis y antigen, and determine the effects of Lewis y antigen on CD44-mediated adhesion and spreading of ovarian cancer cell line RMG-I and the Lewis y antigen-overexpressed cell line RMG-I-H.

Methods

The expression of CD44 in RMG-I and RMG-I-H cells before and after treatment of Lewis y monoclonal antibody was detected by immunocytochemistry; the expression of Lewis y antigen and CD44 was detected by Western Blot. The structural relationship between Lewis y antigen and CD44 was determined by immunoprecipitation and confocal laser scanning microscopy. The adhesion and spreading of RMG-I and RMG-I-H cells on hyaluronic acid (HA) were observed. The expression of CD44 mRNA in RMG-I and RMG-I-H cells was detected by real-time RT-PCR.

Results

Immunocytochemistry revealed that the expression of CD44 was significantly higher in RMG-I-H cells than in RMG-I cells (P < 0.01), and its expression in both cell lines was significantly decreased after treatment of Lewis y monoclonal antibody (both P < 0.01). Western Blot confirmed that the content of CD44 in RMG-I-H cells was 1.46 times of that in RMG-I cells. The co-location of Lewis y antigen and CD44 was confirmed by co-immunoprecipitation. The co-expression of CD44 and Lewis y antigen in RMG-I-H cells was 2.24 times of that in RMG-I cells. The adhesion and spreading of RMG-I-H cells on HA were significantly enhanced as compared to those of RMG-I cells (P < 0.01), and this enhancement was inhibited by Lewis y monoclonal antibody (P < 0.01). The mRNA level of CD44 in both cell lines was similar (P > 0.05).

Conclusion

Lewis y antigen strengthens CD44-mediated adhesion and spreading of ovarian cancer cells.

Lewis (y) antigen overexpression increases the expression of MMP-2 and MMP-9 and invasion of human ovarian cancer cells

Lewis (y) antigen is a difucosylated oligosaccharide present on the plasma membrane, and its overexpression is frequently found in human cancers and has been shown to be associated with poor prognosis. Our previous studies have shown that Lewis (y) antigen plays a positive role in the process of invasion and metastasis of ovarian cancer cells. However, the mechanisms by which Lewis (y) antigen enhances the invasion and tumor metastasis are still unknown. In this study, we established a stable cell line constitutively expressing Lewis (y) antigen (RMG-1-hFUT) by transfecting the cDNA encoding part of the human α1,2-fucosyltransferase (α1,2-FUT) gene into the ovarian cancer cell line RMG-1, and investigated whether Lewis (y) antigen regulates the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9, and tissue inhibitors of metalloproteinases (TIMP-1) and TIMP-2. We found that RMG-1-hFUT cells exhibited higher invasive capacities than their control cells. In addition, expression of TIMP-1 and TIMP-2 was down-regulated and expression of MMP-2 and MMP-9 was up-regulated. Anti-Lewis (y) antigen antibody treatment significantly reversed the expression of TIMP-1, TIMP-2, MMP-2 and MMP-9. Taken together, we provide the first evidence that down-regulation of TIMP-1 and TIMP-2 and up-regulation of MMP-2 and MMP-9 represents one of the mechanisms by which Lewis (y) antigen promotes cell invasion.

Lewis Y promotes growth and adhesion of ovarian carcinoma-derived RMG-I cells by upregulating growth factors

Lewis y (LeY) antigen is a difucosylated oligosaccharide carried by glycoconjugates on the cell surface. Overexpression of LeY is frequently observed in epithelial-derived cancers and has been correlated to the pathological staging and prognosis. However, the effects of LeY on ovarian cancer are not yet clear. Previously, we transfected the ovarian cancer cell line RMG-I with the α1,2-fucosyltransferase gene to obtain stable transfectants, RMG-I-H, that highly express LeY. In the present study, we examined the proliferation, tumorigenesis, adhesion and invasion of the cell lines with treatment of LeY monoclonal antibody (mAb). Additionally, we examined the expression of TGF-β1, VEGF and b-FGF in xenograft tumors. The results showed that the proliferation and adhesion in vitro were significantly inhibited by treatment of RMG-I-H cells with LeY mAb. When subcutaneously inoculated in nude mice, RMG-I-H cells produced large tumors, while mock-transfected cells RMG-I-C and the parental cells RMG-I produced small tumors. Moreover, the tumor formation by RMG-I-H cells was inhibited by preincubating the cells with LeY mAb. Notably, the expression of TGF-β1, VEGF and b-FGF all increased in RMG-I-H cells. In conclusion, LeY plays an important role in promoting cell proliferation, tumorigenecity and adhesion, and these effects may be related to increased levels of growth factors. The LeY antibody shows potential application in the treatment of LeY-positive tumors.