Human beta-galactoside alpha-2,3-sialyltransferase (ST3Gal III) attenuated Taxol-induced apoptosis in ovarian cancer cells by downregulating caspase-8 activity

Cell Membrane Sialome: Sialic Acids as Therapeutic Targets and Regulators of Drug Resistance in Human Cancer Management

A cellular sialome is a physiologically active and dynamically changing component of the cell membrane. Sialylation plays a crucial role in tumor progression, and alterations in cellular sialylation patterns have been described as modulators of chemotherapy effectiveness. However, the precise mechanisms through which altered sialylation contributes to drug resistance in cancer are not yet fully understood. This review focuses on the intricate interplay between sialylation and cancer treatment. It presents the role of sialic acids in modulating cell-cell interactions, the extracellular matrix (ECM), and the immunosuppressive processes within the context of cancer. The issue of drug resistance is also discussed, and the mechanisms that involve transporters, the tumor microenvironment, and metabolism are analyzed. The review explores drugs and therapeutic approaches that may induce modifications in sialylation processes with a primary focus on their impact on sialyltransferases or sialidases. Despite advancements in cellular glycobiology and glycoengineering, an interdisciplinary effort is required to decipher and comprehend the biological characteristics and consequences of altered sialylation. Additionally, understanding the modulatory role of sialoglycans in drug sensitivity is crucial to applying this knowledge in clinical practice for the benefit of cancer patients.

The glycosyltransferase ST3GAL2 modulates virus proliferation and the inflammation response in porcine reproductive and respiratory syndrome virus infection

β-galactoside α-2,3-sialyltransferase 2 (ST3GAL2) is a member of the sialyltransferase family that mediates terminal modification of glycoproteins and glycolipids. ST3GAL2 has been found to play a role in obesity, aging, and malignant diseases. In this study, we cloned porcine ST3GAL2 (pST3GAL2) from porcine alveolar macrophages (PAMs), and its role in porcine reproductive and respiratory syndrome virus (PRRSV) infection was investigated by transcriptome analysis. pST3GAL2 was found to be located in the Golgi apparatus, and it was expressed at high levels in PRRSV-infected PAMs. Overexpression of pST3GAL2 resulted in a slight increase in PRRSV proliferation, and the interaction between pST3GAL2 and GP2a of PRRSV was detected by coimmunoprecipitation and confocal microscopy. The expression of pro-inflammatory cytokines (IFN-β, IL-2, IL-6, IL-18, IL-1β and TNF-α) was significantly inhibited in pST3GAL2-overexpressing, PRRSV-infected cells and upregulated in PRRSV-infected pST3GAL2-knockout cells, while the pattern of expression of anti-inflammatory cytokines (IL-4 and IL-10) was diametrically opposite. Our results demonstrate that the regulation of pST3GAL2 plays an important role in PRRSV proliferation and functional alterations in virus-infected cells. These results contribute to our understanding of the role of β-galactoside α-2,3-sialyltransferase 2 in antiviral immunity.

miR-144-5p and miR-451a Inhibit the Growth of Cholangiocarcinoma Cells Through Decreasing the Expression of ST8SIA4

Accumulating evidences indicate that non-coding RNAs play crucial roles in the progression of an extensive range of carcinomas. This study aimed to investigate the action mechanism of miR-144-5p and miR-451a in cholangiocarcinoma. We found that miR-144-5p and miR-451a were significantly decreased in cholangiocarcinoma patient samples compared to the adjacent normal bile duct samples. The downregulation of these two miRNAs was correlated with a more advanced disease state of cholangiocarcinoma patients. Overexpression of miR-144-5p and miR-451a suppressed the proliferation, invasion and migration of cholangiocarcinoma cells in vitro and inhibited xenograft tumor growth. Knockdown of these two miRNAs had the opposite effects. miR-144-5p and miR-451a regulated the expression of ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 4 (ST8SIA4), and presented a correlation with ST8SIA4 in patient samples. Overexpression of ST8SIA4 promoted the proliferation, invasion and migration of cholangiocarcinoma cells, and the changes were reversed by upregulating the expression of miR-144-5p and miR-451a. Our findings indicated that miR-144-5p and miR-451a displayed a tumor suppressor role through decreasing the expression of ST8SIA4 in cholangiocarcinoma.

Selectins: An Important Family of Glycan-Binding Cell Adhesion Molecules in Ovarian Cancer

Ovarian cancer is the most lethal gynecological malignancy worldwide. Unlike most other tumor types that metastasize via the vasculature, ovarian cancer metastasizes predominantly via the transcoelomic route within the peritoneal cavity. As cancer metastasis accounts for the majority of deaths, there is an urge to better understand its determinants. In the peritoneal cavity, tumor-mesothelial adhesion is an important step for cancer dissemination. Selectins are glycan-binding molecules that facilitate early steps of this adhesion cascade by mediating heterotypic cell-cell interaction under hydrodynamic flow. Here, we review the function and regulation of selectins in peritoneal carcinomatosis of ovarian cancer, and highlight how dysregulation of selectin ligand biogenesis affects disease outcome. Further, we will introduce the latest tools in studying selectin-glycan interaction. Finally, an overview of potential therapeutic intervention points that may lead to the development of efficacious therapies for ovarian cancer is provided.

Design, synthesis and evaluation of carbamate-linked uridyl-based inhibitors of human ST6Gal I

Sialic acid at the terminus of cell surface glycoconjugates is a critical element in cell-cell recognition, receptor binding and immune responses. Sialyltransferases (ST), the enzymes responsible for the biosynthesis of sialylated glycans are highly upregulated in cancer and the resulting hypersialylation of the tumour cell surface correlates strongly with tumour growth, metastasis and drug resistance. Inhibitors of human STs, in particular human ST6Gal I, are thus expected to be valuable chemical tools for the discovery of novel anticancer drugs. Herein, we report on the computationally-guided design and development of uridine-based inhibitors that replace the charged phosphodiester linker of known ST inhibitors with a neutral carbamate to improve pharmacokinetic properties and synthetic accessibility. A series of 24 carbamate-linked uridyl-based compounds were synthesised by coupling aryl and hetaryl α-hydroxyphosphonates with a 5'-amino-5'-deoxyuridine fragment. The inhibitory activities of the newly synthesised compounds against recombinant human ST6Gal I were determined using a luminescent microplate assay, and five promising inhibitors with K_i's ranging from 1 to 20 µM were identified. These results show that carbamate-linked uridyl-based compounds are a potential new class of readily accessible, non-cytotoxic ST inhibitors to be further explored.

Advances in the relationship between glycosyltransferases and multidrug resistance in cancer

Despite great progress in clinical treatment, cancer remains a serious health problem contributing to significant morbidity and mortality worldwide. Although chemotherapy is a common therapeutic measure, multidrug resistance (MDR) presents a major challenge that often leads to poor prognosis. The abnormal expression of glycosyltransferases (GTs) leading to aberrant glycosylation patterns are considered a marker of cancer. Furthermore, the biosynthesis of these glycoconjugates has been associated with tumor proliferation, invasion and metastasis. Recently, studies have found that GTs are involved in mediating MDR in cancer cells through complex mechanisms and can influence therapeutic effect. In this review, we focus on several types of cancers and summarize previous studies on the correlation between GTs and MDR.

Sialyltransferase ST3GAL1 promotes cell migration, invasion, and TGF-β1-induced EMT and confers paclitaxel resistance in ovarian cancer

Sialyltransferases transfer sialic acid to nascent oligosaccharides and are upregulated in cancer. The inhibition of sialyltransferases is emerging as a potential strategy to prevent metastasis in several cancers, including ovarian cancer. ST3GAL1 is a sialyltransferase that catalyzes the transfer of sialic acid from cytidine monophosphate-sialic acid to galactose-containing substrates and is associated with cancer progression and chemoresistance. However, the function of ST3GAL1 in ovarian cancer is uncertain. Herein, we use qRT-PCR, western blotting, and immunohistochemistry to assess the expression of ST3GAL1 in ovarian cancer tissue and cell lines and investigate whether it influences resistance to paclitaxel in vitro and in a mouse xenograft model. We found that ST3GAL1 is upregulated in ovarian cancer tissues and in the ovarian cancer cell lines SKOV-3 and OVCAR3 but downregulated in A2780 ovarian cancer cells. Overexpression of ST3GAL1 in A2780 cells increases cell growth, migration, and invasion whereas ST3GAL1 knockdown in SKOV-3 cells decreases cell growth, migration, and invasion. Furthermore, overexpression of ST3GAL1 increases resistance to paclitaxel while downregulation of ST3GAL1 decreases resistance to paclitaxel in vitro, and overexpression of ST3GAL1 increases tumorigenicity and resistance to paclitaxel in vivo. Transforming growth factor-β1 can increase ST3GAL1 expression and induce ovarian cell epithelial-mesenchymal transition (EMT). However, knockdown of ST3GAL1 inhibits EMT expression. Taken together, our findings have identified a regulatory mechanism involving ST3GAL1 in ovarian cancer. ST3GAL1 may be a promising target for overcoming paclitaxel resistance in ovarian carcinoma.

The role of α2,3-linked sialylation on clear cell type epithelial ovarian cancer

OBJECTIVE

Our previous study has shown that high expression of α2,3-sialytransferase type I was associated with advanced stage serous type epithelial ovarian cancer (EOC). The aim of the current study further attempts to evaluate the altered α 2,3-sialylation on the behavior of clear cell type EOC (C-EOC).

MATERIALS AND METHODS

Immunohistochemistry staining, bioinformatics analysis and tissue array were used to disclose the clinical significance of over α2,3-sialylation in C-EOC. An α2,3 sialylation inhibitor, soyasaponin I (SsaI) was used to investigate the behavior change of the C-EOC cell line.

RESULTS

We reconfirmed that α2,3-sialylation, instead of α2,6- sialylation, was associated with late-stage C-EOC. Soyasaponin I could inhibit α2,3-sialylation of C-EOC cell lines and increase E-cadherin expression with subsequently suppressing migration of C-EOC cells.

CONCLUSIONS

The current study demonstrated the important role of α2,3-linked sialylation in C-EOC and targeting of α2,3-linked sialylation might offer as a potential therapeutic strategy in the future.

α2,3-sialyltransferase type I regulates migration and peritoneal dissemination of ovarian cancer cells

Epithelial ovarian cancer (EOC) has the highest mortality rate among gynecologic cancers due to advanced stage presentation, peritoneal dissemination, and refractory ascites at diagnosis. We investigated the role of α2,3-sialyltransferase type I (ST3GalI) by analyzing human ovarian cancer datasets and human EOC tissue arrays. We found that high expression of ST3GalI was associated with advanced stage EOC. Transwell migration and cell invasion assays showed that high ST3GalI expression enhanced migration of EOC cells. We also observed that there was a linear relation between ST3GalI expression and epidermal growth factor receptor (EGFR) signaling in EOC patients, and that high ST3GalI expression blocked the effect of EGFR inhibitors. Co-Immunoprecipitation experiments demonstrated that ST3GalI and EGFR were present in the same protein complex. Inhibition of ST3GalI using a competitive inhibitor, Soyasaponin I (SsaI), inhibited tumor cell migration and dissemination in the in vivo mouse model with transplanted MOSEC cells. Further, SsaI synergistically enhanced the anti-tumor effects of EGFR inhibitor on EOC cells. Our study demonstrates that ST3GalI regulates ovarian cancer cell migration and peritoneal dissemination via EGFR signaling. This suggests α2,3-linked sialylation inhibitors in combination with EGFR inhibitors could be effective agents for the treatment of EOC.

Upregulation of miR-181c inhibits chemoresistance by targeting ST8SIA4 in chronic myelocytic leukemia

Chemotherapy resistance frequently drives tumor progression. Increased expression of ST8SIA4 has been reported in diverse carcinomas and highly correlates with leukemia multidrug resistance (MDR). MicroRNAs (miRNA) are widely recognized as key players in cancer progression and drug resistance. Here, to explore whether miRNA modulates the sensitivity of chronic myelocytic leukemia (CML) to chemotherapeutic agents and regulates ST8SIA4 expression, we analyzed the complete miRNA expression profile and found a subset of miRNAs specifically dysregulated in adriamycin-resistant CML cell line K562/ADR and its parent cell line K562. Compared with three pairs of CML cell lines and 38 clinical samples of peripheral blood mononuclear cells (PBMC) of CML patients, miR-181c expression was down-regulated in drug-resistant cell lines and CML/MDR samples. Altered expression levels of miR-181c influenced the MDR phenotypes of K562 and K562/ADR. Reporter-gene assay showed that miR-181c directly targeted and inhibited the ST8SIA4 expression, as well as miR-181c was inversely correlated with the levels of ST8SIA4 expression in CML cell lines and samples. Moreover, ST8SIA4 could reverse the effect of miR-181c on drug resistance in K562 and K562/ADR cells in vitro. Upregulation of miR-181c sensitized K562/ADR cells to adriamycin in vivo through directly suppressing ST8SIA4 expression. Further investigation showed that miR-181c mediated the activity of phosphoinositide-3 kinase (PI3K)/AKT signal pathway, and inhibition of PI3K/Akt in K562 cells counteracted miR-181c-mediated MDR phenotype. These data revealed an important role for miR-181c in the regulation of chemoresistance in CML, and suggested the potential application of miR-181c in drug resistance treatment.

Transition state-based ST6Gal I inhibitors: Mimicking the phosphodiester linkage with a triazole or carbamate through an enthalpy-entropy compensation

Human β-galactoside α-2,6-sialyltransferase I (ST6Gal I) catalyses the synthesis of sialylated glycoconjugates. Overexpression of ST6Gal I is observed in many cancers, where it promotes metastasis through altered cell surface sialylation. A wide range of sialyltransferase inhibitors have been developed, with analogues structurally similar to the transition state exhibiting the highest inhibitory activity. To improve synthetic accessibility and pharmacokinetics of previously reported inhibitors, the replacement of the charged phosphodiester linker with a potential neutral isostere such as a carbamate or a 1,2,3-triazole has been investigated. Extensive molecular dynamics simulations have demonstrated that compounds with the alternate linkers could maintain key interactions with the human ST6Gal I active site, demonstrating the potential of a carbamate or a 1,2,3-triazole as a phosphodiester isostere. Free energy perturbation calculations provided energetic evidence suggesting that the carbamate and 1,2,3-triazole were slightly more favourable than the phosphodiester. Further exploration with free energy component, quasi-harmonic and cluster analysis suggested that there is an enthalpy-entropy compensation accounting for the replacement of the flexible charged phosphodiester with a neutral and rigid isostere. Overall, these simulations provide a strong rationale for the use of a carbamate or 1,2,3-triazole as a phosphodiester isostere in the development of novel inhibitors of human ST6Gal I.

MicroRNA-33a and let-7e inhibit human colorectal cancer progression by targeting ST8SIA1

Colorectal cancer (CRC) is one of the leading causes of cancer mortality worldwide. Aberrant sialylation is crucially involved in the progression of various types of cancer. MicroRNAs (miRNAs) have been broadly studied in cancer. MicroRNA-33a (miR-33a) and Has-let-7e (let-7e) are non-coding RNA that can reduce cell motility and viability in cancer. In this study, miR-33a and let-7e levels were confirmed to be significantly down-regulated in CRC samples (n=32) and drug resistant cell line (HCT-8/5-FU) compared with those in the matched adjacent tissues and drug sensitivity cell line (HCT-8). ST8SIA1 was highly expressed in CRC tissues and HCT-8/5-FU cells, which was negatively correlated with miR-33a/let-7e expression. Luciferase reporter assays confirmed that both miR-33a and let-7e bound to the 3'-untranslated (3'-UTR) region of ST8SIA1. Inhibiting miR-33a/let-7e expression in CRC cells increased endogenous ST8SIA1 mRNA and protein levels. MiR-33a/let-7e knockdown promoted chemoresistance, proliferation, invasion, angiogenesis in vitro, and tumor growth in vivo. Whereas, ectopic expression of miR-33a/let-7e suppressed chemoresistance, proliferation, invasion and angiogenesis in CRC cell lines. ST8SIA1 knockdown mimicked the tumor suppressive effect of miR-33a/let-7e on CRC cells, while restoration of ST8SIA1 abolished the tumor suppressive effect of miR-33a/let-7e on CRC cells. Taken together, altered expression of miR-33a/let-7e was correlated with ST8SIA1 level, which might contribute to CRC progression. The miR-33a/let-7e-ST8SIA1 axis could be a therapeutic target for CRC patients.

ST3Gal III modulates breast cancer cell adhesion and invasion by altering the expression of invasion-related molecules

Changes in the carbohydrate structure on the surface of tumor cells is an important feature of cancer metastasis. The specific role of sialic acids in the glycoconjugate terminal has not yet been clearly elucidated in these processes. Previously, we reported that α2,3-sialic acid residues in breast cancer are associated with metastatic potential. The α2,3-sialyltransferase ST3Gal III, which adds α2,3-sialic acids to glycoproteins, is overexpressed in various tumors, and enzyme activity is correlated with tumor metastasis, yet its mechanistic role has not been fully evaluated. In the present study, we aimed to investigate the influence of ST3Gal III on key steps in the process of breast cancer metastasis. ST3Gal III-overexpressing and ST3Gal III-silenced breast cancer MDA-MB-231 cell lines were generated. They showed an increase or decrease in the tumor-associated antigen sialyl-Lewis X (SLeX). The E-selectin binding capacity of the transfectants was proportional to cell surface SLeX levels. Cell migration and invasion were positively correlated with ST3Gal III levels. Moreover, ST3Gal III expression modulated the protein expression of invasion-related molecules, including β1 integrin, matrix metalloproteinase (MMP)-2, MMP-9 and cyclooxygenase-2, which may account for the mechanism involved in the effects of ST3Gal III on breast cancer invasiveness. In conclusion, our findings in these novel models of ST3Gal III expression revealed a critical requirement for ST3Gal III in several steps of breast cancer metastasis. ST3Gal III modulates breast cancer cell adhesion and invasion by altering the expression of invasion-related molecules. This study provides novel insights into the mechanisms underlying metastasis and suggests a new target for the effective drug treatment of breast cancer metastasis.

Effect of ST3GAL 4 and FUT 7 on sialyl Lewis X synthesis and multidrug resistance in human acute myeloid leukemia

Sialyl Lewis X (sLe X, CD15s) is a key antigen produced on tumor cell surfaces during multidrug resistance (MDR) development. The present study investigated the effect of α1, 3 fucosyltransferase VII (FucT VII) and α2, 3 sialyltransferase IV (ST3Gal IV) on sLe X oligosaccharides synthesis as well as their impact on MDR development in acute myeloid leukemia cells (AML). FUT7 and ST3GAL4 were overexpressed in three AML MDR cells and bone marrow mononuclear cells (BMMC) of AML patients with MDR by real-time polymerase chain reaction (PCR). A close association was found between the expression levels of FUT7 and ST3GAL4 and the amount of sLe X oligosaccharides, as well as the phenotypic variation of MDR of HL60 and HL60/ADR cells both in vitro and in vivo. Manipulation of these two genes' expression modulated the activity of phosphoinositide-3 kinase (PI3K)/Akt signaling pathway, thereby regulating the proportionally mutative expression of P-glycoprotein (P-gp) and multidrug resistance related protein 1 (MRP1), both of which are known to be involved in MDR. Blocking the PI3K/Akt pathway by its specific inhibitor LY294002 or Akt short hairpin RNA (shRNA) resulted in the reduced MDR of HL60/ADR cells. This study indicated that sLe X involved in the development of MDR of AML cells probably through FUT7 and ST3GAL4 regulating the activity of PI3K/Akt signaling pathway and the expression of P-gp and MRP1.

Modification of sialylation is associated with multidrug resistance in human acute myeloid leukemia

Aberrant cell surface sialylation patterns have been shown to correlate with tumor progression and metastasis. However, the role of sialylation regulation of cancer multidrug resistance (MDR) remains poorly understood. This study investigated sialylation in modification on MDR in acute myeloid leukemia (AML). Using mass spectrometry (MS) analysis, the composition profiling of sialylated N-glycans differed in three pairs of AML cell lines. Real-time PCR showed the differential expressional profiles of 20 sialyltransferase (ST) genes in the both AML cell lines and bone marrow mononuclear cells (BMMCs) of AML patients. The expression levels of ST3GAL5 and ST8SIA4 were detected, which were overexpressed in HL60 and HL60/adriamycin-resistant (ADR) cells. The altered levels of ST3GAL5 and ST8SIA4 were found in close association with the MDR phenotype changing of HL60 and HL60/ADR cells both in vitro and in vivo. Further data demonstrated that manipulation of these two genes' expression modulated the activity of phosphoinositide-3 kinase (PI3K)/Akt signaling pathway and its downstream target thus regulated the proportionally mutative expression of P-glycoprotein (P-gp) and MDR-related protein 1 (MRP1), both of which are known to be involved in MDR. Blocking the PI3K/Akt pathway by its specific inhibitor LY294002 or by Akt small interfering RNA resulted in the reduced chemosensitivity of HL60/ADR cells. Therefore, this study indicated that sialylation involved in the development of MDR of AML cells probably through ST3GAL5 or ST8SIA4 regulating the activity of PI3K/Akt signaling and the expression of P-gp and MRP1.

Expression patterns of α2,3-sialyltransferase I and α2,6-sialyltransferase I in human cutaneous epithelial lesions

Skin tumors have become one of the most common cancers in the world and their carcinogenesis is frequently associated with altered glycosylation patterns. The aberrant sialylation, a type of glycosylation, can mediate pathophysiological key events during various stages of tumor progression, including invasion and metastasis. Sialyltransferases play a key role in a variety of biological processes, including cell-cell communication, cell-matrix interaction, adhesion, and protein targeting. In this study, it was evaluated the expression of ST3Gal I and ST6Gal I in cutaneous epithelial lesions that include actinic keratosis (n=15), keratoacanthoma (n=9), squamous cell carcinoma (n=22) and basal cell carcinoma (n=28) in order to evaluate if sialyltransferases expression is different in premalignant and in malignant tumors. The expression of ST3Gal I was observed in actinic keratosis (53%), keratoacanthoma (78%), squamous cell carcinoma (73%) and basal cell carcinoma (32%) with statistic differences between basal cell carcinoma and keratoacanthoma (P=0.0239) and basal cell carcinoma and squamous cell carcinoma (P=0.0096); for ST6Gal I, cytoplasmic expression was noted in actinic keratosis (40%), heterogeneous and cytoplasmic expression was noted in keratoacanthoma (67%), squamous cell carcinoma (41%) and basal cell carcinoma (7%) with statistic differences between basal cell carcinoma and squamous cell carcinoma (P=0.0061) and basal cell carcinoma and keratoacanthoma (P=0.0008). In summary, our results showed that the high expression of ST3Gal I and ST6Gal I, in skin tumors, is associated with tumors with greater potential for invasion and metastasis, as in the case of squamous cell carcinoma, and this may be related to their behavior.

Human GM3 Synthase Attenuates Taxol-Triggered Apoptosis Associated with Downregulation of Caspase-3 in Ovarian Cancer Cells

BACKGROUND

Taxol (paclitaxel) inhibits proliferation and induces apoptosis in a variety of cancer cells, but it also upregulates cytoprotective proteins and/or pathways that compromise its therapeutic efficacy.

MATERIALS AND METHOD

The roles of GM3 synthase (α2,3-sialyltransferase, ST3Gal V) in attenuating Taxol-induced apoptosis and triggering drug resistance were determined by cloning and overexpressing this enzyme in the SKOV3 human ovarian cancer cell line, treating SKOV3 and the transfectants (SKOV3/GS) with Taxol and determining apoptosis, cell survival, clonogenic ability, and caspase-3 activation.

RESULTS

In this report, we demonstrated that Taxol treatment resulted in apoptosis which was associated with caspase-3 activation. Taxol treatment upregulated the expression of human GM3 synthase, an enzyme that transfers a sialic acid to lactosylceramide. Moreover, we cloned the full-length GM3 synthase gene and showed for the first time that forced expression of GM3 synthase attenuated Taxol-induced apoptosis and increased resistance to Taxol in SKOV3 cells.

CONCLUSIONS

GM3 synthase overexpression inhibited Taxol-triggered caspase-3 activation, revealing that upregulation of GM3 synthase prevents apoptosis and hence reduces the efficacy of Taxol therapy.

alpha2,3-sialyltransferase ST3Gal III modulates pancreatic cancer cell motility and adhesion in vitro and enhances its metastatic potential in vivo

Background

Cell surface sialylation is emerging as an important feature of cancer cell metastasis. Sialyltransferase expression has been reported to be altered in tumours and may account for the formation of sialylated tumour antigens. We have focused on the influence of alpha-2,3-sialyltransferase ST3Gal III in key steps of the pancreatic tumorigenic process.

Methodology/Principal Findings

ST3Gal III overexpressing pancreatic adenocarcinoma cell lines Capan-1 and MDAPanc-28 were generated. They showed an increase of the tumour associated antigen sialyl-Lewis^x. The transfectants' E-selectin binding capacity was proportional to cell surface sialyl-Lewis^x levels. Cellular migration positively correlated with ST3Gal III and sialyl-Lewis^x levels. Moreover, intrasplenic injection of the ST3Gal III transfected cells into athymic nude mice showed a decrease in survival and higher metastasis formation when compared to the mock cells.

Conclusion

In summary, the overexpression of ST3Gal III in these pancreatic adenocarcinoma cell lines underlines the role of this enzyme and its product in key steps of tumour progression such as adhesion, migration and metastasis formation.