Chondroitin sulfate glycosaminoglycans as major P-selectin ligands on metastatic breast cancer cell lines

The C-type lectin domain of CD62P (P-selectin) functions as an integrin ligand

Recognition of integrins by CD62P has not been reported and this motivated a docking simulation using integrin αvβ3 as a target. We predicted that the C-type lectin domain of CD62P functions as a potential integrin ligand and observed that it specifically bound to soluble β3 and β1 integrins. Known inhibitors of the interaction between CD62P-PSGL-1 did not suppress the binding, whereas the disintegrin domain of ADAM-15, a known integrin ligand, suppressed recognition by the lectin domain. Furthermore, an R16E/K17E mutation in the predicted integrin-binding interface located outside of the glycan-binding site within the lectin domain, strongly inhibited CD62P binding to integrins. In contrast, the E88D mutation that strongly disrupts glycan binding only slightly affected CD62P-integrin recognition, indicating that the glycan and integrin-binding sites are distinct. Notably, the lectin domain allosterically activated integrins by binding to the allosteric site 2. We conclude that CD62P-integrin binding may function to promote a diverse set of cell-cell adhesive interactions given that β3 and β1 integrins are more widely expressed than PSGL-1 that is limited to leukocytes.

VT68.2: An Antibody to Chondroitin Sulfate Proteoglycan 4 (CSPG4) Displays Reactivity against a Tumor-Associated Carbohydrate Antigen

The anti-CSPG4 monoclonal antibodies (mAbs) have shown anti-tumor activity and therapeutic potential for treating breast cancer. In addition, CSPG4 is a dominant tumor-associated antigen that is also involved in normal-tissue development in humans. Therefore, the potential for off-tumor activity remains a serious concern when targeting CSPG4 therapeutically. Previous work suggested that glycans contribute to the binding of specific anti-CSPG4 antibodies to tumor cells, but the specificity and importance of this contribution are unknown. In this study, the reactivity of anti-CSPG4 mAbs was characterized with a peptide mimetic of carbohydrate antigens expressed in breast cancer. ELISA, flow cytometry, and microarray assays were used to screen mAbs for their ability to bind to carbohydrate-mimicking peptides (CMPs), cancer cells, and glycans. The mAb VT68.2 displayed a distinctly strong binding to a CMP (P10s) and bound to triple-negative breast cancer cells. In addition, VT68.2 showed a higher affinity for N-linked glycans that contain terminal fucose and fucosylated lactosamines. The functional assays demonstrated that VT68.2 inhibited cancer cell migration. These results define the glycoform reactivity of an anti-CSPG4 antibody and may lead to the development of less toxic therapeutic approaches that target tumor-specific glyco-peptides.

Theranostic Applications of Glycosaminoglycans in Metastatic Renal Cell Carcinoma

Renal cell carcinoma (RCC) makes up the majority of kidney cancers, with a poor prognosis for metastatic RCC (mRCC). Challenges faced in the management of mRCC, include a lack of reliable prognostic markers and biomarkers for precise monitoring of disease treatment, together with the potential risk of toxicity associated with more recent therapeutic options. Glycosaminoglycans (GAGs) are a class of carbohydrates that can be categorized into four main subclasses, viz., chondroitin sulfate, hyaluronic acid, heparan sulfate and keratan sulfate. GAGs are known to be closely associated with cancer progression and modulation of metastasis by modification of the tumor microenvironment. Alterations of expression, composition and spatiotemporal distribution of GAGs in the extracellular matrix (ECM), dysregulate ECM functions and drive cancer invasion. In this review, we focus on the clinical utility of GAGs as biomarkers for mRCC (which is important for risk stratification and strategizing effective treatment protocols), as well as potential therapeutic targets that could benefit patients afflicted with advanced RCC. Besides GAG-targeted therapies that holds promise in mRCC, other potential strategies include utilizing GAGs as drug carriers and their mimetics to counter cancer progression, and enhance immunotherapy through binding and transducing signals for immune mediators.

Bioactive food components and their inhibitory actions in multiple platelet pathways

In addition to hemostasis and thrombosis, blood platelets are involved in various processes such as inflammation, infection, immunobiology, cancer metastasis, wound repair and angiogenesis. Platelets' hemostatic and non-hemostatic functions are mediated by the expression of various membrane receptors and the release of proteins, ions and other mediators. Therefore, specific activities of platelets responsible for the non-hemostatic disease are to be inhibited while leaving the platelet's hemostatic function unaffected. Platelets' anti-aggregatory property has been used as a primary criterion for antiplatelet drugs/bioactives; however, their non-hemostatic activities are not well known. This review describes the hemostatic and non-hemostatic function of human blood platelets and the modulatory effects of bioactive food components. PRACTICAL APPLICATIONS: In this review, we have discussed the antiplatelet effects of several food components. These bioactive compounds inhibit both hemostatic and non-hemostatic pathways involving blood platelet. Platelets have emerged as critical biological factors of normal and pathologic vascular healing and other diseases such as cancers and inflammatory and immune disorders. The challenge for therapeutic intervention in these disorders will be to find drugs and bioactive compounds that preferentially block specific sites implicated in emerging roles of platelets' complicated contribution to inflammation, tumour growth, or other disorders while leaving at least some of their hemostatic function intact.

Role of extracellular matrix proteoglycans in immune cell recruitment

Leucocyte recruitment is a critical component of the immune response and is central to our ability to fight infection. Paradoxically, leucocyte recruitment is also a central component of inflammatory-based diseases such as rheumatoid arthritis, atherosclerosis and cancer. The role of the extracellular matrix, in particular proteoglycans, in this process has been largely overlooked. Proteoglycans consist of protein cores with glycosaminoglycan sugar side chains attached. Proteoglycans have been shown to bind and regulate the function of a number of proteins, for example chemokines, and also play a key structural role in the local tissue environment/niche. Whilst they have been implicated in leucocyte recruitment and inflammatory disease, their mechanistic function has yet to be fully understood, precluding therapeutic targeting. This review summarizes what is currently known about the role of proteoglycans in the different stages of leucocyte recruitment and proposes a number of areas where more research is needed. A better understanding of the mechanistic role of proteoglycans during inflammatory disease will inform the development of next-generation therapeutics.

Chondroitin sulfate-mediated albumin corona nanoparticles for the treatment of breast cancer

Chondroitin sulfate-mediated albumin corona nanoparticles were readily prepared without any chemical reaction, and their active tumor targeting and therapeutic effects were examined. Negatively charged chondroitin sulfate (CS) and positively charged doxorubicin (DOX) self-assembled into nanoparticles (CS-DOX-NPs) via electrostatic interactions. Bovine serum albumin (BSA) was then adsorbed on the surface of CS-DOX-NPs to form albumin corona nanoparticles (BC-DOX-NPs) protected from endogenous proteins. Due to the dual effect of BSA and CS, BC-DOX-NPs interacted with the gp60, SPARC and CD44 receptors on tumor cells, facilitating their rapid and efficient transcytosis and improving their accumulation and uptake within tumor tissues. The simultaneous presence of BSA and CS also allowed BC-DOX-NPs to target CD44 efficiently, leading to greater cellular uptake and cytotoxicity against 4T1 cells than CS-DOX-NPs or free DOX. Intravenous injection of BC-DOX-NPs into orthotopic 4T1 tumor-bearing mice led to greater drug accumulation at the tumor site than with CS-DOX-NPs or free DOX, resulting in significant inhibition of tumor growth and lower exposure of major organs to the drug.

MicroRNA-128 Confers Anti-Endothelial Adhesion and Anti-Migration Properties to Counteract Highly Metastatic Cervical Cancer Cells' Migration in a Parallel-Plate Flow Chamber

Despite the distant metastasis of cervical cancer cells being a prominent cause of mortality, neither the metastasis capacity nor the in vitro conditions mimicking adhesion of cervical cancer cells to endothelial cells have been fully elucidated. Circulating metastatic cancer cells undergo transendothelial migration and invade normal organs in distant metastasis; however, the putative molecular mechanism remains largely uncertain. In this study, we describe the use of an in vitro parallel-plate flow chamber to simulate the dynamic circulation stress on cervical cancer cells and elucidate their vascular adhesion and metastasis. We isolate the viable and shear stress-resistant (SSR) cervical cancer cells for mechanistic studies. Remarkably, the identified SSR-HeLa and SSR-CaSki exhibited high in vitro adhesive and metastatic activities. Hence, a consistently suppressed miR-128 level was revealed in SSR cell clones compared to those of parental wild-type (WT) cells. Overexpressed miR-128 attenuated SSR-HeLa cells’ adherence to human umbilical cord vein endothelial cells (HUVECs); in contrast, suppressed miR-128 efficiently augmented the static adhesion capacity in WT-HeLa and WT-CaSki cells. Hence, amplified miR-128 modestly abolished in vitro SSR-augmented HeLa and CaSki cell movement, whereas reduced miR-128 aggravated the migration speed in a time-lapse recording assay in WT groups. Consistently, the force expression of miR-128 alleviated the SSR-enhanced HeLa and CaSki cell mobility in a wound healing assay. Notably, miR-128 mediated SSR-enhanced HeLa and CaSki cells’ adhesion and metastasis through suppressed ITGA5, ITGB5, sLex, CEACAM-6, MMP9, and MMP23 transcript levels. Our data provide evidence suggesting that miR-128 is a promising microRNA that prevented endothelial cells’ adhesion and transendothelial migration to contribute to the SSR-enhanced adhesion and metastasis progression under a parallel-plate flow chamber system. This indicates that the nucleoid-based miR-128 strategy may be an attractive therapeutic strategy to eliminate tumor cells resistant to circulation shear flow, prevent vascular adhesion, and preclude subsequent transendothelial metastasis.

Chondroitin sulfate-hybridized zein nanoparticles for tumor-targeted delivery of docetaxel

Chondroitin sulfate-hybridized zein nanoparticles (zein/CS NPs) were developed for targeted delivery of docetaxel, which exhibited mean diameters of 157.8 ± 3.6 nm and docetaxel encapsulation efficiency of 64.2 ± 1.9 %. Docetaxel was released from the NPs in a sustained manner (∼72 h), following first-order kinetics. The zein/CS NPs showed improved colloidal stability, maintaining the initial size in serum for 12 h. The pre-treatment of CS reduced the uptake efficiency of the NPs by 23 % in PC-3 cells, suggesting the involvement of CD44-mediated uptake mechanism. The NPs showed 2.79-fold lower IC₅₀ values than free docetaxel. Enhanced tumor accumulation of the NPs was confirmed in PC-3 xenograft mice by near-infrared fluorescence imaging (35.3-fold, versus free Cy5.5). The NPs exhibited improved pharmacokinetic properties (9.5-fold longer terminal half-life, versus free docetaxel) and anti-tumor efficacy comparable to Taxotere with negligible systemic toxicity, suggesting zein/CS NPs could be a promising nanoplatform for targeted cancer therapy.

Carbohydrate (Chondroitin 4) Sulfotransferase-11-Mediated Induction of Epithelial-Mesenchymal Transition and Generation of Cancer Stem Cells

INTRODUCTION

We have previously shown that the expression of carbohydrate (chondroitin 4) sulfotransferase-11 (CHST11) is elevated in human breast cancer tissues, and that its expression in human breast cancer cell lines is associated with aggressive behavior of cells. The clinical significance of CHST11 expression is unknown, and its function in breast cancer cells is not fully understood.

OBJECTIVE

The current study was performed to define the clinical significance of this gene and address its biological function in promoting the aggressive behavior of breast cancer cells.

METHODS

Publicly available datasets were analyzed to determine the correlation of CHST11 expression with breast cancer survival. MCF-7 cells were transfected with the human CHST11 gene, and MCF-7-CHST11 cells with stable expression of the gene were established. Morphology and metastatic capacity of transfected cells were monitored in vitro. E-cadherin and β-catenin expression was compared by immunofluorescence. The expression of genes involved in epithelial-mesenchymal transition (EMT) and pluripotency was determined using real-time PCR. The Wnt inhibitor, Wnt-C59, was used to examine the involvement of Wnt in CHST11-mediated morphology.

RESULTS

The elevated expression of CHST11 in breast tumor specimens was significantly associated with poor survival among patients. MCF-7-CHST11 cells displayed morphological characteristics consistent with EMT, together with a significantly higher proliferation rate, enhanced migratory potential, and more robust anchorage-independent growth. MCF-7-CHST11 cells showed decreased expression of E-cadherin and increased accumulation of β-catenin, as assessed by immunofluorescence. Consistently, increased expression of CHST11 resulted in upregulation of key EMT and stem cell markers. Morphological transition in MCF-7-CHST11 cells was partially reversed by co-incubation with an inhibitor of the Wnt pathway.

CONCLUSIONS

Our findings support a role for CHST11 in induction of EMT and stem cell-like properties. Our data also associate the expression levels of CHST11 in breast tumor specimens with patients' survival. The results have a significant implication for CHST11 expression level as a novel molecular signature for predictive and prognostic purposes in breast cancer. Moreover, with a possible role in driving tumor cell aggressiveness, CHST11 expression might be further considered as a potential therapeutic target for breast cancer.

Systematic analysis of the human tumor cell binding to human vs. murine E- and P-selectin under static vs. dynamic conditions

Endothelial E- and P-selectins promote metastasis formation by interacting with sialyl-Lewis X and A (sLeX/sLeA) on circulating tumor cells. This interaction precedes extravasation and can take place under dynamic and static conditions. Metastasis formation is often studied in xenograft models. However, it is unclear whether species differences exist in the ligand specificity of human (h) vs. murine (m) selectins and whether different ligands are functional under dynamic vs. static conditions. We systematically compared the h vs. m E- and P-selectin (ESel/PSel) binding of a range of human tumor cells under dynamic vs. static conditions. The tumor cells were categorized by their sLeA/X status (sLeA+/sLeX+, sLeA−/sLeX+ and sLeA−/sLeX−). The general biological nature of the tumor–selectin interaction was analyzed by applying several tumor cell treatments (anti-sLeA/X blockade, neuraminidase, pronase and inhibition of O/N-glycosylation). We observed remarkable differences in the static vs. dynamic interaction of tumor cells with h vs. m ESel/PSel depending on their sLeA/X status. The tumor cell treatments mostly affected either static or dynamic as well as either h- or m-selectin interaction. mESel showed a higher diversity of potential ligands than hESel. Inhibition of O-GalNAc-glycosylation also affected glycosphingolipid synthesis. Summarized, different ligands on human tumor cells are functional under static vs. dynamic conditions and for the interaction with human vs. murine ESel/PSel. Non-canonical selectin ligands lacking the sLeA/X glycan epitopes exist on human tumor cells. These findings have important implications for the current development of glycomimetic, antimetastatic drugs and encourage the development of immunodeficient mice with humanized selectins.

Galectin-3 Regulates the Expression of Tumor Glycosaminoglycans and Increases the Metastatic Potential of Breast Cancer

Galectin-3 (Gal-3) is a multifunctional β-galactoside-binding lectin that once synthesized is expressed in the nucleus, cytoplasm, cell surface, and extracellular environment. Gal-3 plays an important role in breast cancer tumors due to its ability to promote interactions between cell-cell and cell-extracellular matrix (ECM) elements, increasing tumor survival and metastatic dissemination. Still, the mechanism by which Gal-3 interferes with tumor cell migration and metastasis formation is complex and not fully understood. Here, we showed that Gal-3 knockdown increased the migration ability of 4T1 murine breast cancer cells in vitro. Using the 4T1 orthotopic breast cancer spontaneous metastasis mouse model, we demonstrated that 4T1-derived tumors were significantly larger in the presence of Gal-3 (scramble) in comparison with Gal-3 knockdown 4T1-derived tumors. Nevertheless, Gal-3 knockdown 4T1 cells were outnumbered in the bone marrow in comparison with scramble 4T1 cells. Finally, we reported here a decrease in the content of cell-surface syndecan-1 and an increase in the levels of chondroitin sulfate proteoglycans such as versican in Gal-3 knockdown 4T1 cells both in vitro and in vivo. Overall, our findings establish that Gal-3 downregulation during breast cancer progression regulates cell-associated and tumor microenvironment glycosaminoglycans (GAGs)/proteoglycans (PG), thus enhancing the metastatic potential of tumor cells.

ECM-Mimetic Multiresponsive Nanobullets Targeted Against Metastasizing Circulating Tumor Clusters in Breast Cancer

Targeting smaller populations of circulating tumor clusters (CTC) with tumor-initiating and colonization potentials at distant sites in circulation remains a challenge as clusters possess both epithelial and mesenchymal characteristics. Bullet shaped ellipsoidal nanostructures of size 600 ± 11.3 nm (major axis) and 281.9 ± 5.3 nm (minor axis) with 2.2 aspect ratio were self-assembled using inorganic and organic GRAS biomaterials to preferentially target tumor-causing CTCs. Negatively-charged chondroitin sulfate in presence of gelatin guides unidirectional growth of calcium carbonate mesocrystals to form nanobullets, mediates CD44 targeting of CTCs. Switchable multi-responsive drug release profiles (temperature and pH) were recorded for nanobullets promoting spontaneous and efficient cell-killing. CD44 and E-cadherin overexpressing 'seeding' cell clusters of 170 ± 22 µm were developed as in vitro CTC model. pH responsive release of Dox into lysosome stimulates calcium influx resulting in cell death. CD44-blocked CTCs showed significantly reduced internalization when compared to CD44-expressing CTCs thereby confirming CD44 specific internalization of nanobullets. Significantly retarded expansion of clusters when shifted to cell adhesive surfaces depicts the potential of nanobullets against colonization of CTCs. Hence, newer insights on developed anisotropic ECM-mimetic nanohybrids would enhance targeted capture of tumor-initiating clusters in systemic circulation that would potentially reduce the progression of tumor in breast cancer patients.

Glycosylation in the Tumor Microenvironment: Implications for Tumor Angiogenesis and Metastasis

Just as oncogene activation and tumor suppressor loss are hallmarks of tumor development, emerging evidence indicates that tumor microenvironment-mediated changes in glycosylation play a crucial functional role in tumor progression and metastasis. Hypoxia and inflammatory events regulate protein glycosylation in tumor cells and associated stromal cells in the tumor microenvironment, which facilitates tumor progression and also modulates a patient's response to anti-cancer therapeutics. In this review, we highlight the impact of altered glycosylation on angiogenic signaling and endothelial cell adhesion, and the critical consequences of these changes in tumor behavior.

The dual role of the glycosaminoglycan chondroitin-6-sulfate in the development, progression and metastasis of cancer

The remarkable structural heterogeneity of chondroitin sulfate (CS) and dermatan sulfate (DS) generates biological information that can be unique to each of these glycosaminoglycans (GAGs), and changes in their composition are translated into alterations in the binding profiles of these molecules. CS/DS can bind to various cytokines and growth factors, cell surface receptors, adhesion molecules, enzymes and fibrillar glycoproteins of the extracellular matrix, thereby influencing both cell behavior and the biomechanical and biochemical properties of the matrix. In this review, we summarize the current knowledge concerning CS/DS metabolism in the human cancer stroma. The remodeling of the GAG profile in the tumor niche is manifested as a substantial increase in the CS content and a gradual decrease in the proportion between DS and CS. Furthermore, the composition of CS and DS is also affected, which results in a substantial increase in the 6‐O‐sulfated and/or unsulfated disaccharide content, which is concomitant with a decrease in the 4‐O‐sulfation level. Here, we discuss the possible impact of alterations in the CS/DS sulfation pattern on the binding capacity and specificity of these GAGs. Moreover, we propose potential consequences of the stromal accumulation of chondroitin‐6‐sulfate for the progression and metastasis of cancer.

Chondroitin sulfate derived theranostic nanoparticles for targeted drug delivery

Glycosaminoglycan derived nanoparticles are a promising delivery system owing to their unique tumour targeting ability. Exploiting fluorescein for inducing amphiphilicity in these biopolymers provides inherent imaging and drug stabilization capabilities by π-π stacking interactions with aromatic antineoplastic agents. This offers a versatile and highly customizable nanocarrier with narrow size distribution and high drug loading efficiency (80%) with sustained drug release.

Biodiversity of CS–proteoglycan sulphation motifs: chemical messenger recognition modules with roles in information transfer, control of cellular behaviour and tissue morphogenesis

Chondroitin sulphate (CS) glycosaminoglycan chains on cell and extracellular matrix proteoglycans (PGs) can no longer be regarded as merely hydrodynamic space fillers. Overwhelming evidence over recent years indicates that sulphation motif sequences within the CS chain structure are a source of significant biological information to cells and their surrounding environment. CS sulphation motifs have been shown to interact with a wide variety of bioactive molecules, e.g. cytokines, growth factors, chemokines, morphogenetic proteins, enzymes and enzyme inhibitors, as well as structural components within the extracellular milieu. They are therefore capable of modulating a panoply of signalling pathways, thus controlling diverse cellular behaviours including proliferation, differentiation, migration and matrix synthesis. Consequently, through these motifs, CS PGs play significant roles in the maintenance of tissue homeostasis, morphogenesis, development, growth and disease. Here, we review (i) the biodiversity of CS PGs and their sulphation motif sequences and (ii) the current understanding of the signalling roles they play in regulating cellular behaviour during tissue development, growth, disease and repair.

Role of protein glycosylation in cancer metastasis

Although altered glycosylation has been detected in human cancer cells decades ago, only investigations in the last years have enormously increased our knowledge about the details of protein glycosylation and its role in tumour progression. Many proteins, which are heavily glycosylated, i.e. adhesion proteins or proteases, play an important role in cancer metastasis that represents the crucial and frequently life-threatening step in progression of most tumour types. Compared to normal tissue, tumour cells often show altered glycosylation patters with appearance of new tumour-specific antigens. In this review, we give an overview about the role of glycosylation in tumour metastasis, describing recent results about O-glycans, N-glycans and glycosaminoglycans. We show that glycan structures, glycosylated proteins and glycosylation enzymes have influence on different steps of the metastatic process, including epithelial-mesenchymal transition (EMT), migration, invasion/intravasation and extravasation of tumour cells. Regarding the important role of cancer metastasis for patients survival, further knowledge about the consequences of altered glycosylation patterns in tumour cells is needed which might eventually lead to the development of novel therapeutic approaches.

Development of Sialic Acid-coated Nanoparticles for Targeting Cancer and Efficient Evasion of the Immune System

Evading the reticuloendothelial system (RES) remains a critical challenge in the development of efficient delivery and diagnostic systems for cancer. Sialic acid (N-acetylneuraminic acid, Neu5Ac) is recognized as a "self" marker by major serum protein complement factor H and shows reduced interaction with the innate immune system via sialic acid-binding immunoglobulin-like lectin (Siglec), which is known as one of the significant regulators of phagocytic evasion. Accordingly, we prepared different surface-modified gold nanoparticles (AuNPs) and investigated the effects of sialic acid on cellular and immune responses of nanoparticles in vitro and in vivo. Sialic acid modification not only facilitates evasion of the RES by suppressing the immune response, but also enhances tumor accumulation via its active targeting ability. Therefore, sialic acid modification presents a promising strategy to advance nanotechnology towards the prospect of clinical translation.

C-type lectins facilitate tumor metastasis

Metastasis, a life-threatening complication of cancer, leads to the majority of cases of cancer-associated mortality. Unfortunately, the underlying molecular and cellular mechanisms of cancer metastasis remain to be fully elucidated. C-type lectins are a large group of proteins, which share structurally homologous carbohydrate-recognition domains (CRDs) and possess diverse physiological functions, including inflammation and antimicrobial immunity. Accumulating evidence has demonstrated the contribution of C-type lectins in different steps of the metastatic spread of cancer. Notably, a substantial proportion of C-type lectins, including selectins, mannose receptor (MR) and liver and lymph node sinusoidal endothelial cell C-type lectin, are important molecular targets for the formation of metastases in vitro and in vivo. The present review summarizes what has been found regarding C-type lectins in the lymphatic and hematogenous metastasis of cancer. An improved understanding the role of C-type lectins in cancer metastasis provides a comprehensive perspective for further clarifying the molecular mechanisms of cancer metastasis and supports the development of novel C-type lectins-based therapies the for prevention of metastasis in certain types of cancer.

Chondroitin sulfate-capped super-paramagnetic iron oxide nanoparticles as potential carriers of doxorubicin hydrochloride

Chondroitin-4-sulfate (CS), a glycosaminoglycan, was used to prepare CS-capped super-paramagnetic iron oxide nanoparticles, which were further employed for loading a water-soluble chemotherapeutic agent (doxorubicin hydrochloride, DOX). CS-capped SPIONs have potential biomedical application in cancer targeting. The optimized formulation had a hydrodynamic size of 91.2±0.8nm (PDI; 0.228±0.004) and zeta potential of -49.1±1.66mV. DOX was loaded onto the formulation up to 2% (w/w) by physical interaction with CS. TEM showed nano-sized particles having a core-shell structure. XRD confirmed crystal phase of iron oxide. FT-IR conceived the interaction of iron oxide with CS as bidentate chelation and also confirmed DOX loading. Vibration sample magnetometry confirmed super-paramagnetic nature of nanoparticles, with saturation magnetization of 0.238emug(-1). In vitro release profile at pH 7.4 showed that 96.67% of DOX was released within 24h (first order kinetics). MTT assay in MCF7 cells showed significantly higher (p<0.0001) cytotoxicity for DOX in SPIONs than DOX solution (IC50 values 6.294±0.4169 and 11.316±0.1102μgmL(-1), respectively).

Inhibition of Cell Proliferation and Growth of Pancreatic Cancer by Silencing of Carbohydrate Sulfotransferase 15 In Vitro and in a Xenograft Model

Chondroitin sulfate E (CS-E), a highly sulfated glycosaminoglycan, is known to promote tumor invasion and metastasis. Because the presence of CS-E is detected in both tumor and stromal cells in pancreatic ductal adenocarcinoma (PDAC), multistage involvement of CS-E in the development of PDAC has been considered. However, its involvement in the early stage of PDAC progression is still not fully understood. In this study, to clarify the direct role of CS-E in tumor, but not stromal, cells of PDAC, we focused on carbohydrate sulfotransferase 15 (CHST15), a specific enzyme that biosynthesizes CS-E, and investigated the effects of the CHST15 siRNA on tumor cell proliferation in vitro and growth in vivo. CHST15 mRNA is highly expressed in the human pancreatic cancer cell lines PANC-1, MIA PaCa-2, Capan-1 and Capan-2. CHST15 siRNA significantly inhibited the expression of CHST15 mRNA in these four cells in vitro. Silencing of the CHST15 gene in the cells was associated with significant reduction of proliferation and up-regulation of the cell cycle inhibitor-related gene p21^CIP1/WAF1. In a subcutaneous xenograft tumor model of PANC-1 in nude mice, a single intratumoral injection of CHST15 siRNA almost completely suppressed tumor growth. Reduced CHST15 protein signals associated with tumor necrosis were observed with the treatment with CHST15 siRNA. These results provide evidence of the direct action of CHST15 on the proliferation of pancreatic tumor cells partly through the p21^CIP1/WAF1 pathway. Thus, CHST15-CS-E axis-mediated tumor cell proliferation could be a novel therapeutic target in the early stage of PDAC progression.

Prognostic impact of chondroitin-4-sulfotransferase CHST11 in ovarian cancer

Ovarian cancer (OvCa) accounts for the highest tumor-related mortality among gynecological malignancies, but the underlying mechanisms are poorly understood. Glycosaminoglycans are abundantly present in ovarian tumors, and there is rising evidence that chondroitin sulfate (CS) as well as diverse carbohydrate sulfotransferases (CHSTs), the enzymes involved in the sulfation process of these structures, plays an important role in metastatic spread of tumor cells. mRNA expression levels of CHST3/7/11/12/13/15 were compared between malignant (86 OvCas) and non-malignant tumors (6 borderline tumors and 3 cystadenomas). CHST11 and CHST15 were further chosen for Western blot analysis in a cohort of 216 OvCas. Protein expression levels were correlated with clinicopathologic prognostic parameters and survival data. A significantly higher mRNA expression of CHST11, CHST12, and CHST15 was measured in ovarian cancer samples in comparison to non-malignant ones, and the same trend was observed for CHST13. For CHST3 and CHST7, no significant differences were found between the two groups. At protein level, high CHST11 expression was independently associated with unfavorable progression-free survival (PFS; p = 0.027). A similar trend was observed for CHST15, showing a nearly significant correlation between high expression levels and shorter recurrence-free survival in patients without macroscopic residual tumor after surgery (p = 0.053). We conclude that CHSTs involved in the synthesis of CS-A and CS-E might influence ovarian cancer progression, and we suggest CHST11 as independent unfavorable prognostic factor in this entity.

CHST11 gene expression and DNA methylation in breast cancer

Our previously published data link P-selectin-reactive chondroitin sulfate structures on the surface of breast cancer cells to metastatic behavior of cells. We have shown that a particular sulfation pattern mediated by the expression of carbohydrate (chondroitin 4) sulfotransferase-11 (CHST11) correlates with P-selectin binding and aggressiveness of human breast cancer cell lines. The present study was performed to evaluate the prognostic value of CHST11 expression and determine whether aberrant DNA methylation controls CHST11 expression in breast cancer. Publicly available datasets were used to examine the association of CHST11 expression to aggressiveness and progression of breast cancer. Methylation status was analyzed using bisulfite genomic sequencing. 5-aza-2′-deoxycytidine (5AzadC) was used for DNA demethylation. Reduced representation bisulfite sequencing was performed in the CpG island of CHST11 with a minimum coverage of 10. Quantitative real-time RT-PCR was employed to confirm the expression profile of CHST11 in breast cancer cell lines. Flow cytometry was also used to confirm the expression of the CHST11 product, chondroitin sulfate A (CS-A). The expression of CHST11 was significantly higher in basal-like and Her2-amplified cell lines compared to luminal cell lines. CHST11 was also highly expressed in cancer tissues compared to normal tissues and the expression levels were significantly associated with tumor progression. We observed very low levels of DNA methylation in a CpG island of CHST11 in basal-like cells but very high levels in the same region in luminal cells. Treatment of MCF7 cells, a luminal cell line with very low expression of CHST11, with 5AzadC increased the expression of CHST11 and its immediate product, CS-A, in a dose-dependent manner. These results suggest that CHST11 may play a direct role in progression of breast cancer and that its expression is controlled by DNA methylation. Therefore, in addition to CHST11 mRNA levels, the methylation status of this gene also has potential as a prognostic biomarker.

Gray platelet syndrome: proinflammatory megakaryocytes and α-granule loss cause myelofibrosis and confer metastasis resistance in mice

NBEAL2 encodes a multidomain scaffolding protein with a putative role in granule ontogeny in human platelets. Mutations in NBEAL2 underlie gray platelet syndrome (GPS), a rare inherited bleeding disorder characterized by a lack of α-granules within blood platelets and progressive bone marrow fibrosis. We present here a novel Nbeal2(-/-) murine model of GPS and demonstrate that the lack of α-granules is due to their loss from platelets/mature megakaryocytes (MKs), and not by initial impaired formation. We show that the lack of Nbeal2 confers a proinflammatory phenotype to the bone marrow MKs, which in combination with the loss of proteins from α-granules drives the development of bone marrow fibrosis. In addition, we demonstrate that α-granule deficiency impairs platelet function beyond their purely hemostatic role and that Nbeal2 deficiency has a protective effect against cancer metastasis.

Enhancing radiotherapy by lipid nanocapsule-mediated delivery of amphiphilic gold nanoparticles to intracellular membranes

Amphiphilic gold nanoparticles (amph-NPs), composed of gold cores surrounded by an amphiphilic mixed organic ligand shell, are capable of embedding within and traversing lipid membranes. Here we describe a strategy using crosslink-stabilized lipid nanocapsules (NCs) as carriers to transport such membrane-penetrating particles into tumor cells and promote their transfer to intracellular membranes for enhanced radiotherapy of cancer. We synthesized and characterized interbilayer-crosslinked multilamellar lipid vesicles (ICMVs) carrying amph-NPs embedded in the capsule walls, forming Au-NCs. Confocal and electron microscopies revealed that the intracellular distribution of amph-NPs within melanoma and breast tumor cells following uptake of free particles vs Au-NCs was quite distinct and that amph-NPs initially delivered into endosomes by Au-NCs transferred over a period of hours to intracellular membranes through tumor cells, with greater intracellular spread in melanoma cells than breast carcinoma cells. Clonogenic assays revealed that Au-NCs enhanced radiotherapeutic killing of melanoma cells. Thus, multilamellar lipid capsules may serve as an effective carrier to deliver amphiphilic gold nanoparticles to tumors, where the membrane-penetrating properties of these materials can significantly enhance the efficacy of frontline radiotherapy treatments.

Chondroitin sulfate-E is a negative regulator of a pro-tumorigenic Wnt/beta-catenin-Collagen 1 axis in breast cancer cells

Expression of the glycosaminoglycan chondroitin sulfate-E (CS-E) is misregulated in many human cancers, including breast cancer. Cell-surface associated CS-E has been shown to have pro-tumorigenic functions, and pharmacological treatment with exogenous CS-E has been proposed to interfere with tumor progression mediated by endogenous CS-E. However, the effects of exogenous CS-E on breast cancer cell behavior, and the molecular mechanisms deployed by CS-E are not well understood. We show here that treatment with CS-E, but not other chondroitin forms, could interfere with the invasive protrusion formation and migration of breast cancer cells in three-dimensional organotypic cultures. Microarray analysis identified transcriptional programs controlled by CS-E in these cells. Importantly, negative regulation of the pro-metastatic extracellular matrix gene Col1a1 was required for the anti-migratory effects of exogenous CS-E. Knock-down of Col1a1 gene expression mimics the effects of CS-E treatment, while exposing cells to a preformed collagen I matrix interfered with the anti-migratory effects of CS-E. In addition, CS-E specifically interfered with Wnt/beta-catenin signaling, a known pro-tumorigenic pathway. Lastly, we demonstrate that Col1a1 is a positively regulated target gene of the Wnt/beta-catenin pathway in breast cancer cells. Together, our data identify treatment with exogenous CS-E as negative regulatory mechanism of breast cancer cell motility through interference with a pro-tumorigenic Wnt/beta-catenin - Collagen I axis.

c-FOS suppresses ovarian cancer progression by changing adhesion

Background:

C-Fos was initially described as oncogene, but was associated with favourable prognosis in ovarian cancer (OvCa) patients. The molecular and functional aspects underlying this effect are still unknown.

Methods:

Using stable transfectants of SKOV3 and OVCAR8 cells, proliferation, migration, invasion and apoptotic potential of c-FOS-overexpressing clones and controls were compared. Adherence to components of the extracellular matrix was analysed in static assays, and adhesion to E-selectin, endothelial and mesothelial cells in dynamic flow assays. The effect of c-FOS in vivo was studied after intraperitoneal injection of SKOV3 clones into SCID mice, and changes in gene expression were determined by microarray analysis.

Results:

Tumour growth after injection into SCID mice was strongly delayed by c-FOS overexpression, with reduction of lung metastases and circulating tumour cells. In vitro, c-FOS had only weak influence on proliferation and migration, but was strongly pro-apoptotic. Adhesion to components of the extracellular matrix (collagen I, IV) and to E-selectin, endothelial and mesothelial cells was significantly reduced in c-FOS-overexpressing OvCa cells. This corresponds to deregulation of adhesion proteins and glycosylation enzymes in microarray analysis.

Conclusion:

In addition to its known pro-apoptotic effect, c-FOS might influence OvCa progression by changing the adhesion of OvCa cells to peritoneal surfaces.

Physical biology in cancer. 3. The role of cell glycocalyx in vascular transport of circulating tumor cells

Circulating tumor cells (CTCs) in blood are known to adhere to the luminal surface of the microvasculature via receptor-mediated adhesion, which contributes to the spread of cancer metastasis to anatomically distant organs. Such interactions between ligands on CTCs and endothelial cell-bound surface receptors are sensitive to receptor-ligand distances at the nanoscale. The sugar-rich coating expressed on the surface of CTCs and endothelial cells, known as the glycocalyx, serves as a physical structure that can control the spacing and, thus, the availability of such receptor-ligand interactions. The cancer cell glycocalyx can also regulate the ability of therapeutic ligands to bind to CTCs in the bloodstream. Here, we review the role of cell glycocalyx on the adhesion and therapeutic treatment of CTCs in the bloodstream.

Heparan sulfate and heparanase as modulators of breast cancer progression

Breast cancer is defined as a cancer originating in tissues of the breast, frequently in ducts and lobules. During the last 30 years, studies to understand the biology and to treat breast tumor improved patients' survival rates. These studies have focused on genetic components involved in tumor progression and on tumor microenvironment. Heparan sulfate proteoglycans (HSPGs) are involved in cell signaling, adhesion, extracellular matrix assembly, and growth factors storage. As a central molecule, HSPG regulates cell behavior and tumor progression. HS accompanied by its glycosaminoglycan counterparts regulates tissue homeostasis and cancer development. These molecules present opposite effects according to tumor type or cancer model. Studies in this area may contribute to unveil glycosaminoglycan activities on cell dynamics during breast cancer exploring these polysaccharides as antitumor agents. Heparanase is a potent tumor modulator due to its protumorigenic, proangiogenic, and prometastatic activities. Several lines of evidence indicate that heparanase is upregulated in all human sarcomas and carcinomas. Heparanase seems to be related to several aspects regulating the potential of breast cancer metastasis. Due to its multiple roles, heparanase is seen as a target in cancer treatment. We will describe recent findings on the function of HSPGs and heparanase in breast cancer behavior and progression.

Over-sulfated glycosaminoglycans are alternative selectin ligands: insights into molecular interactions and possible role in breast cancer metastasis

Distant metastasis account for about 90 % of cancer associated deaths, and yet the oncology field is cruelly lacking tools to accurately predict and/or prevent metastasis. Distant metastasis occurs when circulating tumor cells interact with the endothelium of distant organs and extravasate from the blood vessel into the surrounding tissue. Selectins are a family of carbohydrate receptors well depicted for their role in tumor cells extravasation. They mediate primary interactions of cancer cells with endothelial cells, as well as secondary interactions with leucocytes and platelets, which are also promoting metastasis. The cancer associated carbohydrate antigen sialyl-Lewis x (sLe(x)) has been repeatedly shown to be involved, as selectin ligand, in these interactions. However, recent studies have highlighted that glycosaminoglycans (GAGs), another class of glycans, may also serve as ligands for selectins. We report herein that cancer-associated GAGs are differentially recognized by selectins according to their density of sulfation and the pH conditions of the binding. We also show that these parameters regulate platelets-cancer cells heterotypic aggregation, supporting the idea that GAGs may have pro-metastatic function. Combining our experimental results with in depth analyses of molecular dockings, we propose a model of GAG/selectin interactions robust enough to recapitulate the differential binding of selectins to GAGs, the competition between GAGs and sLe(x) for selectin binding and the effect of sub-physiological pH on GAGs affinities towards selectins. Altogether, our data suggest GAGs to be good ligands for selectins, potentially promoting distant metastasis in a complementary way to sLe(x).

Expression of N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase involved in chondroitin sulfate synthesis is responsible for pulmonary metastasis

Chondroitin sulfate (CS) containing E-disaccharide units, glucuronic acid-N-acetylgalactosamine(4, 6-O-disulfate), at surfaces of tumor cells plays a key role in tumor metastasis. However, the molecular mechanism of the metastasis involving the CS chain-containing E-units is not fully understood. In this study, to clarify the role of E-units in the metastasis and to search for potential molecular targets for anticancer drugs, the isolation and characterization of Lewis lung carcinoma (LLC) cells stably downregulated by the knockdown for the gene encoding N-acetylgalactosamine 4-O-sulfate 6-O-sulfotransferase (GalNAc4S-6ST), which is responsible for the formation of E-units in CS chains, were performed. Knockdown of GalNAc4S-6ST in LLC cells resulted in a reduction in the proportion of E-units, in adhesiveness to extracellular matrix adhesion molecules and in proliferation in vitro. Furthermore, the stable downregulation of GalNAc4S-6ST expression in LLC cells markedly inhibited the colonization of the lungs by inoculated LLC cells and invasive capacity of LLC cells. These results provide clear evidence that CS chain-containing E-units and/or GalNAc4S-6ST play a crucial role in pulmonary metastasis at least through the increased adhesion and the invasive capacity of LLC cells and also provides insights into future drug targets for anticancer treatment.

Role of GalNAc4S-6ST in astrocytic tumor progression

N-Acetylgalactosamine 4-sulfate 6-O-sulfotransferase (GalNAc4S-6ST) is the sulfotransferase responsible for biosynthesis of highly sulfated chondroitin sulfate CS-E. Although involvements of CS-E in neuronal cell functions have been extensively analyzed, the role of GalNAc4S-6ST in astrocytic tumor progression remains unknown. Here, we reveal that GalNAc4S-6ST transcripts were detected in astrocytic tumors derived from all 30 patients examined using quantitative reverse transcription-PCR analysis. Patients with high GalNAc4S-6ST mRNA expression had significantly worse outcome compared with patients with low expression, and multivariate survival analysis disclosed that GalNAc4S-6ST is an independent poor prognostic factor for astrocytic tumors. We then tested whether CS-E enhanced haptotaxic migration of glioblastoma U251-MG cells that endogenously express both the CS-E's scaffold tyrosine phosphatase ζ (PTPζ) and GalNAc4S-6ST, in the presence of CS-E's preferred ligands, pleiotrophin (PTN) or midkine (MK), using a modified Boyden chamber method. Haptotaxic stimulation of cell migration by PTN was most robust on control siRNA-transfected U251-MG cells, while that enhancing effect was cancelled following transduction of GalNAc4S-6ST siRNA. Similar results were obtained using MK, suggesting that both PTN and MK enhance migration of U251-MG cells by binding to CS-E. We also found that PTPζ as well as PTN and MK were frequently expressed in astrocytic tumor cells. Thus, our findings indicate that GalNAc4S-6ST mRNA expressed by astrocytic tumor cells is associated with poor patient prognosis likely by enhancing CS-E-mediated tumor cell motility in the presence of PTN and/or MK.

Horizontal gene transfer contributed to the evolution of extracellular surface structures: the freshwater polyp Hydra is covered by a complex fibrous cuticle containing glycosaminoglycans and proteins of the PPOD and SWT (sweet tooth) families

The single-cell layered ectoderm of the fresh water polyp Hydra fulfills the function of an epidermis by protecting the animals from the surrounding medium. Its outer surface is covered by a fibrous structure termed the cuticle layer, with similarity to the extracellular surface coats of mammalian epithelia. In this paper we have identified molecular components of the cuticle. We show that its outermost layer contains glycoproteins and glycosaminoglycans and we have identified chondroitin and chondroitin-6-sulfate chains. In a search for proteins that could be involved in organising this structure we found PPOD proteins and several members of a protein family containing only SWT (sweet tooth) domains. Structural analyses indicate that PPODs consist of two tandem β-trefoil domains with similarity to carbohydrate-binding sites found in lectins. Experimental evidence confirmed that PPODs can bind sulfated glycans and are secreted into the cuticle layer from granules localized under the apical surface of the ectodermal epithelial cells. PPODs are taxon-specific proteins which appear to have entered the Hydra genome by horizontal gene transfer from bacteria. Their acquisition at the time Hydra evolved from a marine ancestor may have been critical for the transition to the freshwater environment.

More than matrix: the multifaceted role of decorin in cancer

The small leucine-rich proteoglycan, decorin, has incrementally been shown to be a powerful inhibitor of growth in a wide variety of tumour cells, an effect specifically mediated by the interaction of decorin core protein with the epidermal growth factor receptor (EGFR) and other ErbB family proteins. Nowadays, this matrikine has become the main focus of various cancer studies. Decorin is an important component of the cellular microenvironment or extracellular matrix (ECM). Its interactions with matrix and cell membrane components have been implicated in many physiological and pathophysiological processes including matrix organisation, signal transduction, wound healing, cell migration, inhibition of metastasis, and angiogenesis. This review summarises recent findings on decorin's interactions and behaviour related to cancer. Highlighted are key functions of decorin such as interaction with cell surface receptors, as well as with ECM components, and the therapeutic potential of this multifunctional molecule.

Expression of E-selectin ligands on circulating tumor cells: cross-regulation with cancer stem cell regulatory pathways?

Although significant progress has been made in the fight against cancer, successful treatment strategies have yet to be developed to combat those tumors that have metastasized to distant organs. Poor characterization of the molecular mechanisms of cancer spread is a major impediment to designing predictive diagnostics and effective clinical interventions against late stage disease. In hematogenous metastasis, it is widely suspected that circulating tumor cells (CTCs) express specific adhesion molecules that actively initiate contact with the vascular endothelium lining the vessel walls of the target organ. This "tethering" is mediated by ligands expressed by CTCs that bind to E-selectin expressed by endothelial cells. However, it is currently unknown whether expression of functional E-selectin ligands on CTCs is related to cancer stem cell regulatory or maintenance pathways, particularly epithelial-to-mesenchymal transition and the reverse, mesenchymal-to-epithelial transition. In this hypothesis and theory article, we explore the potential roles of these mechanisms on the dynamic regulation of selectin ligands mediating CTC trafficking during metastasis.

Iduronic acid in chondroitin/dermatan sulfate: biosynthesis and biological function

The ability of chondroitin/dermatan sulfate (CS/DS) to convey biological information is enriched by the presence of iduronic acid. DS-epimerases 1 and 2 (DS-epi1 and 2), in conjunction with DS-4-O-sulfotransferase 1, are the enzymes responsible for iduronic acid biosynthesis and will be the major focus of this review. CS/DS proteoglycans (CS/DS-PGs) are ubiquitously found in connective tissues, basement membranes, and cell surfaces or are stored intracellularly. Such wide distribution reflects the variety of biological roles in which they are involved, from extracellular matrix organization to regulation of processes such as proliferation, migration, adhesion, and differentiation. They play roles in inflammation, angiogenesis, coagulation, immunity, and wound healing. Such versatility is achieved thanks to their variable composition, both in terms of protein core and the fine structure of the CS/DS chains. Excellent reviews have been published on the collective and individual functions of each CS/DS-PG. This short review presents the biosynthesis and functions of iduronic acid-containing structures, also as revealed by the analysis of the DS-epi1- and 2-deficient mouse models.

Receptor for advanced glycation end products (RAGE) functions as receptor for specific sulfated glycosaminoglycans, and anti-RAGE antibody or sulfated glycosaminoglycans delivered in vivo inhibit pulmonary metastasis of tumor cells

Altered expression of chondroitin sulfate (CS) and heparan sulfate (HS) at the surfaces of tumor cells plays a key role in malignant transformation and tumor metastasis. Previously we demonstrated that a Lewis lung carcinoma (LLC)-derived tumor cell line with high metastatic potential had a higher proportion of E-disaccharide units, GlcUA-GalNAc(4,6-O-disulfate), in CS chains than low metastatic LLC cells and that such CS chains are involved in the metastatic process. The metastasis was markedly inhibited by the pre-administration of CS-E from squid cartilage rich in E units or by preincubation with a phage display antibody specific for CS-E. However, the molecular mechanism of the inhibition remains to be investigated. In this study the receptor molecule for CS chains containing E-disaccharides expressed on LLC cells was revealed to be receptor for advanced glycation end products (RAGE), which is a member of the immunoglobulin superfamily predominantly expressed in the lung. Interestingly, RAGE bound strongly to not only E-disaccharide, but also HS-expressing LLC cells. Furthermore, the colonization of the lungs by LLC cells was effectively inhibited by the blocking of CS or HS chains at the tumor cell surface with an anti-RAGE antibody through intravenous injections in a dose-dependent manner. These results provide the clear evidence that RAGE is at least one of the critical receptors for CS and HS chains expressed at the tumor cell surface and involved in experimental lung metastasis and that CS/HS and RAGE are potential molecular targets in the treatment of pulmonary metastasis.

Glycomechanics of the metastatic cascade: tumor cell-endothelial cell interactions in the circulation

Hydrodynamic shear force plays an important role in the leukocyte adhesion cascade that involves the tethering and rolling of cells along the endothelial layer, their firm adhesion or arrest, and their extravasation or escape from the circulatory system by inducing passive deformation, or cell flattening, and microvilli stretching, as well as regulating the expression, distribution, and conformation of adhesion molecules on leukocytes and the endothelial layer. Similarly, the dissemination of circulating tumor cells (CTCs) from the primary tumor sites is believed to involve tethering, rolling, and firm adhesion steps before their eventual extravasation which leads to secondary tumor sites (metastasis). Of particular importance to both the leukocyte adhesion cascade and the extravasation of CTCs, glycoproteins are involved in all three steps (capture, rolling, and firm adhesion) and consist of a variety of important selectin ligands. This review article provides an overview of glycoprotein glycosylation associated with the abnormal glycan expression on cancer cell surfaces, where well-established and novel selectin ligands that are cancer related are discussed. An overview of computational approaches on the effects of fluid mechanical force on glycoprotein mediated cancer cell rolling and adhesion is presented with a highlight of recent flow-based and selectin-mediated cell capturing/enriching devices. Finally, as an important branch of the glycoprotein family, mucins, specifically MUC1, are discussed in the context of their aberrant expression on cancer cells and their role as cancer cell adhesion molecules. Since metastasis relies heavily on glycoprotein interactions in the bloodstream where the fluid shear stress highly regulates cell adhesion forces, it is important to study and understand the glycomechanics of all relevant glycoproteins (well-established and novel) as they relate to the metastatic cascade.

Selectin ligand sialyl-Lewis x antigen drives metastasis of hormone-dependent breast cancers

The glycome acts as an essential interface between cells and the surrounding microenvironment. However, changes in glycosylation occur in nearly all breast cancers, which can alter this interaction. Here, we report that profiles of glycosylation vary between ER-positive and ER-negative breast cancers. We found that genes involved in the synthesis of sialyl-Lewis x (sLe(x); FUT3, FUT4, and ST3GAL6) are significantly increased in estrogen receptor alpha-negative (ER-negative) tumors compared with ER-positive ones. SLe(x) expression had no influence on the survival of patients whether they had ER-negative or ER-positive tumors. However, high expression of sLe(x) in ER-positive tumors was correlated with metastasis to the bone where sLe(x) receptor E-selectin is constitutively expressed. The ER-positive ZR-75-1 and the ER-negative BT20 cell lines both express sLe(x) but only ZR-75-1 cells could adhere to activated endothelial cells under dynamic flow conditions in a sLe(x) and E-selectin-dependent manner. Moreover, L/P-selectins bound strongly to ER-negative MDA-MB-231 and BT-20 cell lines in a heparan sulfate (HS)-dependent manner that was independent of sLe(x) expression. Expression of glycosylation genes involved in heparan biosynthesis (EXT1 and HS3ST1) was increased in ER-negative tumors. Taken together, our results suggest that the context of sLe(x) expression is important in determining its functional significance and that selectins may promote metastasis in breast cancer through protein-associated sLe(x) and HS glycosaminoglycans.

Chondroitin sulfates play a major role in breast cancer metastasis: a role for CSPG4 and CHST11 gene expression in forming surface P-selectin ligands in aggressive breast cancer cells

Introduction

We have previously demonstrated that chondroitin sulfate glycosaminoglycans (CS-GAGs) on breast cancer cells function as P-selectin ligands. This study was performed to identify the carrier proteoglycan (PG) and the sulfotransferase gene involved in synthesis of the surface P-selectin-reactive CS-GAGs in human breast cancer cells with high metastatic capacity, as well as to determine a direct role for CS-GAGs in metastatic spread.

Methods

Quantitative real-time PCR (qRT-PCR) and flow cytometry assays were used to detect the expression of genes involved in the sulfation and presentation of chondroitin in several human breast cancer cell lines. Transient transfection of the human breast cancer cell line MDA-MB-231 with the siRNAs for carbohydrate (chondroitin 4) sulfotransferase-11 (CHST11) and chondroitin sulfate proteoglycan 4 (CSPG4 ) was used to investigate the involvement of these genes in expression of surface P-selectin ligands. The expression of CSPG4 and CHST11 in 15 primary invasive breast cancer clinical specimens was assessed by qRT-PCR. The role of CS-GAGs in metastasis was tested using the 4T1 murine mammary cell line (10 mice per group).

Results

The CHST11 gene was highly expressed in aggressive breast cancer cells but significantly less so in less aggressive breast cancer cell lines. A positive correlation was observed between the expression levels of CHST11 and P-selectin binding to cells (P < 0.0001). Blocking the expression of CHST11 with siRNA inhibited CS-A expression and P-selectin binding to MDA-MB-231 cells. The carrier proteoglycan CSPG4 was highly expressed on the aggressive breast cancer cell lines and contributed to the P-selectin binding and CS-A expression. In addition, CSPG4 and CHST11 were over-expressed in tumor-containing clinical tissue specimens compared with normal tissues. Enzymatic removal of tumor-cell surface CS-GAGs significantly inhibited lung colonization of the 4T1 murine mammary cell line (P = 0.0002).

Conclusions

Cell surface P-selectin binding depends on CHST11 gene expression. CSPG4 serves as a P-selectin ligand through its CS chain and participates in P-selectin binding to the highly metastatic breast cancer cells. Removal of CS-GAGs greatly reduces metastatic lung colonization by 4T1 cells. The data strongly indicate that CS-GAGs and their biosynthetic pathways are promising targets for the development of anti-metastatic therapies.

Signaling mechanism of cell adhesion molecules in breast cancer metastasis: potential therapeutic targets

Metastasis is responsible for the majority of breast cancer-related deaths. The metastatic spread of cancer cells is a complicated process that requires considerable flexibility in the adhesive properties of both tumor cells and other interacting cells. Cell adhesion molecules (CAMs) are membrane receptors that mediate cell-cell and cell-matrix interactions, and are essential for transducing intracellular signals responsible for adhesion, migration, invasion, angiogensis, and organ-specific metastasis. This review will discuss the recent advances in our understanding on the biological functions, signaling mechanisms, and therapeutic potentials of important CAMs involved in breast cancer metastasis.

Dermatan sulfate and bone marrow mononuclear cells used as a new therapeutic strategy after arterial injury in mice

BACKGROUND AIMS

Previously, we have demonstrated that administration of dermatan sulfate (DS) suppresses neointima formation in the mouse carotid artery by activating heparin co-factor II. A similar suppressive effect was observed by increasing the number of progenitor cells in circulation. In this study, we investigated the combination of DS and bone marrow mononuclear cells (MNC), which includes potential endothelial progenitors, in neointima formation after arterial injury.

METHODS

Arterial injury was induced by mechanical dilation of the left common carotid artery. We analyzed the extension of endothelial lesion, thrombus formation, P-selectin expression and CD45(+) cell accumulation 1 and 3 days post-injury, and neointima formation 21 days post-injury. Animals were injected with MNC with or without DS during the first 48 h after injury.

RESULTS

The extension of endothelial lesion was similar in all groups 1 day after surgery; however, in injured animals treated with MNC and DS the endothelium recovery seemed to be more efficient 21 days after lesion. Treatment with DS inhibited thrombosis, decreased CD45(+) cell accumulation and P-selectin expression at the site of injury, and reduced the neointimal area by 56%. Treatment with MNC reduced the neointimal area by 54%. The combination of DS and MNC reduced neointima formation by more than 91%. In addition, DS promoted a greater accumulation of MNC at the site of injury.

CONCLUSIONS

DS inhibits the initial thrombotic and inflammatory processes after arterial injury and promotes migration of MNC to the site of the lesion, where they may assist in the recovery of the injured endothelium.