Epithelial syndecan-1 expression is associated with stage and grade in colorectal cancer

Proteolytic signaling in cancer

INTRODUCTION

Cancer is a disease of (altered) biological pathways, often driven by somatic mutations and with several implications. Therefore, the identification of potential markers of disease is challenging. Given the large amount of biological data generated with omics approaches, oncology has experienced significant contributions. Proteomics mapping of protein fragments, derived from proteolytic processing events during oncogenesis, may shed light on (i) the role of active proteases and (ii) the functional implications of processed substrates in biological signaling circuits. Both outcomes have the potential for predicting diagnosis/prognosis in diseases like cancer. Therefore, understanding proteolytic processing events and their downstream implications may contribute to advances in the understanding of tumor biology and targeted therapies in precision medicine.

AREAS COVERED

Proteolytic events associated with some hallmarks of cancer (cell migration and proliferation, angiogenesis, metastasis, as well as extracellular matrix degradation) will be discussed. Moreover, biomarker discovery and the use of proteomics approaches to uncover proteolytic signaling events will also be covered.

EXPERT OPINION

Proteolytic processing is an irreversible protein post-translational modification and the deconvolution of biological data resulting from the study of proteolytic signaling events may be used in both patient diagnosis/prognosis and targeted therapies in cancer.

Heparan sulfate proteoglycans in cancer: Pathogenesis and therapeutic potential

The heparan sulfate proteoglycans (HSPGs) are glycoproteins that consist of a proteoglycan "core" protein and covalently attached heparan sulfate (HS) chain. HSPGs are ubiquitously expressed in mammalian cells on the cell surface and in the extracellular matrix (ECM) and secretory vesicles. Within HSPGs, the protein cores determine when and where HSPG expression takes place, and the HS chains mediate most of HSPG's biological roles through binding various protein ligands, including cytokines, chemokines, growth factors and receptors, morphogens, proteases, protease inhibitors, and ECM proteins. Through these interactions, HSPGs modulate cell proliferation, adhesion, migration, invasion, and angiogenesis to display essential functions in physiology and pathology. Under physiological conditions, the expression and localization of HSPGs are finely regulated to orchestrate their physiological functions, and this is disrupted in cancer. The HSPG dysregulation elicits multiple oncogenic signaling, including growth factor signaling, ECM and Integrin signaling, chemokine and immune signaling, cancer stem cell, cell differentiation, apoptosis, and senescence, to prompt cell transformation, proliferation, tumor invasion and metastasis, tumor angiogenesis and inflammation, and immunotolerance. These oncogenic roles make HSPGs an attractive pharmacological target for anti-cancer therapy. Several therapeutic strategies have been under development, including anti-HSPG antibodies, peptides and HS mimetics, synthetic xylosides, and heparinase inhibitors, and shown promising anti-cancer efficacy. Therefore, much progress has been made in this line of study. However, it needs to bear in mind that the roles of HSPGs in cancer can be either oncogenic or tumor-suppressive, depending on the HSPG and the cancer cell type with the underlying mechanisms that remain obscure. Further studies need to address these to fill the knowledge gap and rationalize more efficient therapeutic targeting.

Alterations of the Extracellular Matrix in Colorectal Carcinoma

Background: The process of proliferation and invasion of tumor cells depends on changes in the extracellular matrix (ECM) through the activation of enzymes and alterations in the profile of ECM components. Our aims are to investigate the mRNA and protein expression profiles of the ECM components, heparanase-1 (HPSE), heparanase-2 (HPSE2), matrix metalloproteinase-9 (MMP-9), and syndecan-1 (SDC1) in neoplastic and nonneoplastic tissues of 24 patients with colorectal carcinoma (CRC) and to test for associations between these expression patterns with the presence or absence of lymph node metastasis. Materials and Methods: This was a cross-sectional study in which 24 adult patients with CRC were admitted for resectional surgery. We analyzed the mRNA and protein expression patterns of the HPSE, HPSE2, MMP-9, and SDC1 genes by quantitative reverse transcription PCR and immunohistochemistry, respectively. Additionally, we investigated whether variations exist in the expression of the ECM components between the affected tissue and nontumoral tissue collected from the same patient. Tissue samples were collected immediately after the surgical resection. Results and Conclusion: The data showed higher mRNA and protein expression levels of HPSE2 (p = 0.0058), MMP-9 (p = 0.0268), and SDC1 (p = 0.0002) in tumor samples when compared with the nonneoplastic tissues. There was, however, only an increase in the level of the HPSE protein in the tumoral tissues. Increased expression of HPSE2 was observed in patients with lymph node metastasis (p = 0.031). This elevation in HPSE2 mRNA expression in patients with lymph node metastasis potentially indicates that it may participate in driving colorectal carcinoma progression.

Targeting Syndecan-1: New Opportunities in Cancer Therapy

Syndecan-1 (SDC1, CD138) is one of the heparan sulfate proteoglycans and is essential for maintaining normal cell morphology, interacting with extracellular and intracellular protein repertoire as well as mediating signaling transduction upon environmental stimuli. The critical role of SDC1 in promoting tumorigenesis and metastasis has been increasingly recognized in various cancer types, implying a promising potential of utilizing SDC1 as a novel target for cancer therapy. This review summarizes the current knowledge on SDC1 structure and functions, including its role in tumor biology. We also discuss the highlights and limitations of current SDC1-targeted therapies as well as the obstacles in developing new therapeutic methods, offering our perspective on the future directions to target SDC1 for cancer treatment.

Cell-surface heparan sulfate proteoglycans as multifunctional integrators of signaling in cancer

Proteoglycans (PGs) represent a large proportion of the components that constitute the extracellular matrix (ECM). They are a diverse group of glycoproteins characterized by a covalent link to a specific glycosaminoglycan type. As part of the ECM, heparan sulfate (HS)PGs participate in both physiological and pathological processes including cell recruitment during inflammation and the promotion of cell proliferation, adhesion and motility during development, angiogenesis, wound repair and tumor progression. A key function of HSPGs is their ability to modulate the expression and function of cytokines, chemokines, growth factors, morphogens, and adhesion molecules. This is due to their capacity to act as ligands or co-receptors for various signal-transducing receptors, affecting pathways such as FGF, VEGF, chemokines, integrins, Wnt, notch, IL-6/JAK-STAT3, and NF-κB. The activation of those pathways has been implicated in the induction, progression, and malignancy of a tumor. For many years, the study of signaling has allowed for designing specific drugs targeting these pathways for cancer treatment, with very positive results. Likewise, HSPGs have become the subject of cancer research and are increasingly recognized as important therapeutic targets. Although they have been studied in a variety of preclinical and experimental models, their mechanism of action in malignancy still needs to be more clearly defined. In this review, we discuss the role of cell-surface HSPGs as pleiotropic modulators of signaling in cancer and identify them as promising markers and targets for cancer treatment.

Syndecan-1 Promotes Hepatocyte-Like Differentiation of Hepatoma Cells Targeting Ets-1 and AP-1

Syndecan-1 is a transmembrane heparan sulfate proteoglycan which is indispensable in the structural and functional integrity of epithelia. Normal hepatocytes display strong cell surface expression of syndecan-1; however, upon malignant transformation, they may lose it from their cell surfaces. In this study, we demonstrate that re-expression of full-length or ectodomain-deleted syndecan-1 in hepatocellular carcinoma cells downregulates phosphorylation of ERK1/2 and p38, with the truncated form exerting an even stronger effect than the full-length protein. Furthermore, overexpression of syndecan-1 in hepatoma cells is associated with a shift of heparan sulfate structure toward a highly sulfated type specific for normal liver. As a result, cell proliferation and proteolytic shedding of syndecan-1 from the cell surface are restrained, which facilitates redifferentiation of hepatoma cells to a more hepatocyte-like phenotype. Our results highlight the importance of syndecan-1 in the formation and maintenance of differentiated epithelial characteristics in hepatocytes partly via the HGF/ERK/Ets-1 signal transduction pathway. Downregulation of Ets-1 expression alone, however, was not sufficient to replicate the phenotype of syndecan-1 overexpressing cells, indicating the need for additional molecular mechanisms. Accordingly, a reporter gene assay revealed the inhibition of Ets-1 as well as AP-1 transcription factor-induced promoter activation, presumably an effect of the heparan sulfate switch.

Involvement of Syndecan-1 and Heparanase in Cancer and Inflammation

The cell surface heparan sulfate proteoglycan Syndecan-1 acts as an important co-receptor for receptor tyrosine kinases and chemokine receptors, and as an adhesion receptor for structural glycoproteins of the extracellular matrix. It serves as a substrate for heparanase, an endo-β-glucuronidase that degrades specific domains of heparan sulfate carbohydrate chains and thereby alters the functional status of the proteoglycan and of Syndecan-1-bound ligands. Syndecan-1 and heparanase show multiple levels of functional interactions, resulting in mutual regulation of their expression, processing, and activity. These interactions are of particular relevance in the context of inflammation and malignant disease. Studies in animal models have revealed a mechanistic role of Syndecan-1 and heparanase in the regulation of contact allergies, kidney inflammation, multiple sclerosis, inflammatory bowel disease, and inflammation-associated tumorigenesis. Moreover, functional interactions between Syndecan-1 and heparanase modulate virtually all steps of tumor progression as defined in the Hallmarks of Cancer. Due to their prognostic value in cancer, and their mechanistic involvement in tumor progression, Syndecan-1 and heparanase have emerged as important drug targets. Data in preclinical models and preclinical phase I/II studies have already yielded promising results that provide a translational perspective.

The Good and Bad Sides of Heparanase-1 and Heparanase-2

In this chapter, we will emphasize the importance of heparan sulfate proteoglycans (HSPG) in controlling various physiological and pathological molecular mechanisms and discuss how the heparanase enzyme can modulate the effects triggered by HSPG. Additionally, we will also navigate about the existing knowledge of the possible role of heparanase-2 in biological events. Heparan sulfate is widely distributed and evolutionarily conserved, evidencing its vital importance in cell development and functions such as cell proliferation, migration, adhesion, differentiation, and angiogenesis. During remodeling of the extracellular matrix, the breakdown of heparan sulfate by heparanase results in the release of molecules containing anchored glycosaminoglycan chains of great interest in heparanase-mediated cell signaling pathways in various physiological states, tumor development, inflammation, and other diseases. Taken together, it appears that heparanase plays a key role in the maintenance of the pathology of cancer and inflammatory diseases and is a potential target for anti-cancer therapies. Therefore, heparanase inhibitors are currently being examined in clinical trials as novel cancer therapeutics. Heparanase-2 has no enzymatic activity, displays higher affinity for heparan sulfate and the coding region alignment shows 40% identity with the heparanase gene. Heparanase-2 plays an important role in embryogenic development however its mode of action and biological function remain to be elucidated. Heparanase-2 functions as an inhibitor of the heparanase-1 enzyme and also inhibits neovascularization mediated by VEGF. The HPSE2 gene is repressed by the Polycomb complex, together suggesting a role as a tumor suppressor.

Serum and tissue syndecan-1 levels in renal cell carcinoma

Background

The proteoglycan syndecan-1 is involved in cell proliferation, adhesion and angiogenesis. It was shown to be involved in cancer progression in different tumor entities. So far, the role of syndecan-1 in renal cell carcinoma (RCC), one of the most common diseases in urologic oncology, was little described. Purpose of the present study was to obtain serum concentrations and tissue expression levels of syndecan-1 in a cohort of patients diagnosed with RCC.

Methods

Clinical and follow-up data were obtained from 413 RCC patients. SDC1 levels were determined in serum samples of 100 patients by enzyme-linked immunosorbent assay and tissue SDC1 expression was measured by immunohistochemistry (IHC) in 343 cases. Results were correlated with clinicopathological and follow-up data.

Results

Five and ten years overall and cancer specific survival were 67% and 56% [overall survival (OS)] and 79% and 76% [cancer-specific survival (CSS)]. In female patients and locally advanced disease (≥T3), tissue SDC1 expression was decreased (female 85.6% vs. male 71.1% low tissue SDC1 expression, P=0.0153 and ≤T2 70.0% vs. ≥T3 87.2% low tissue SDC1 expression, P=0.0055) compared to male patients and organ confined disease. Locally advanced tumor stage, presence of lymph node or distant metastases, high Fuhrman grading and clear cell carcinoma as histopathological subtype were independent prognostic factors for reduced CSS and OS. There was no impact of serum SDC1 (sSDC1) serum concentration or SDC1 tissue protein expression on OS, CSS or recurrence free survival (RFS) in uni- or multivariable analysis.

Conclusions

sSDC1 concentration or SDC1 tissue protein expression levels had no influence on patients' prognosis in the present cohort of patients diagnosed with RCC.

Syndecan-1-Dependent Regulation of Heparanase Affects Invasiveness, Stem Cell Properties, and Therapeutic Resistance of Caco2 Colon Cancer Cells

The heparan sulfate proteoglycan Syndecan-1 binds cytokines, morphogens and extracellular matrix components, regulating cancer stem cell properties and invasiveness. Syndecan-1 is modulated by the heparan sulfate-degrading enzyme heparanase, but the underlying regulatory mechanisms are only poorly understood. In colon cancer pathogenesis, complex changes occur in the expression pattern of Syndecan-1 and heparanase during progression from well-differentiated to undifferentiated tumors. Loss of Syndecan-1 and increased expression of heparanase are associated with a change in phenotypic plasticity and an increase in invasiveness, metastasis and dedifferentiation. Here we investigated the regulatory and functional interplay of Syndecan-1 and heparanase employing siRNA-mediated silencing and plasmid-based overexpression approaches in the human colon cancer cell line Caco2. Heparanase expression and activity were upregulated in Syndecan-1 depleted cells. This increase was linked to an upregulation of the transcription factor Egr1, which regulates heparanase at the promoter level. Inhibitor experiments demonstrated an impact of focal adhesion kinase, Wnt and ROCK-dependent signaling on this process. siRNA-depletion of Syndecan-1, and upregulation of heparanase increased the colon cancer stem cell phenotype based on sphere formation assays and phenotypic marker analysis (Side-population, NANOG, KLF4, NOTCH, Wnt, and TCF4 expression). Syndecan-1 depletion increased invasiveness of Caco2 cells in vitro in a heparanase-dependent manner. Finally, upregulated expression of heparanase resulted in increased resistance to radiotherapy, whereas high expression of enzymatically inactive heparanase promoted chemoresistance to paclitaxel and cisplatin. Our findings provide a new avenue to target a stemness-associated signaling axis as a therapeutic strategy to reduce metastatic spread and cancer recurrence.

The potential of hypericin and hyperforin for antiadhesion therapy to prevent metastasis of parental and oxaliplatin-resistant human adenocarcinoma cells (HT-29)

Cancer cells disseminate to other parts of the body during metastasis through the process of intravasation. The hypericin and hyperforin effect has been described to understand the signal mechanisms that stimulate or stunt cancer cell sprouting to metastasis on colon adenocarcinoma cells HT-29 and its resistant form HT-29-OxR. We focused on the key points of adhesion proteins (cadherin, integrin, selectin and syndecan) and also proteins participating in or contributing to the process of cancer cell migration and adhesion through genes expression and proteins levels. Treatment effects were identified as a consequence of decreased cell adhesion, changes of expression in the adhesive proteins as well as basal membrane degradation associated with changes in the expression of matrix proteinases and in their activity. Finally, the cells affected by hypericin or hyperforin were evaluated by monitoring the cancer cell adhesion properties and proliferation processes. Supplementary Fig. (Supplemental digital content 1, http://links.lww.com/ACD/A267).

Loss of SDC1 Expression Is Associated with Poor Prognosis of Colorectal Cancer Patients in Northern China

Background

Syndecan-1 (SDC1/CD138) is a key cell surface adhesion molecule essential for maintaining cell morphology and the interactions with the surrounding microenvironment. SDC1 tumor immunoexpression may be increased or decreased in epithelial malignant neoplasms compared to that in adjacent non-neoplastic tissue, depending on the type of carcinoma, and it has been correlated with various clinicopathological parameters and patient prognosis. SDC1 expression is decreased in colorectal cancer (CRC) tissue, but the relationship between prognosis and SDC1 expression in CRC patients is controversial.

Methods

In this study, SDC1 expression was detected in 65 adjacent non-neoplastic colorectal tissues, 477 CRCs, and 79 metastatic lymph nodes using tissue microarray.

Results

The data show that SDC1 decreased in CRC tissues (p ≤ 0.001) and metastatic lymph node tissues (p ≤ 0.001) compared to that in adjacent non-neoplastic colorectal tissues. Loss of SDC1 protein expression is associated with poor overall (p < 0.0001) and disease-free survival (p < 0.0001), differentiation (p = 0.017), stage (p ≤ 0.001), and lymph node metastasis (p ≤ 0.001) in CRC patients.

Conclusions

These data suggest that the loss of SDC1 plays an important role in CRC malignant progression. Loss of SDC1 expression indicates poor prognosis in patients from northern China with CRC.

MicroRNA-494 acts as a tumor suppressor in pancreatic cancer, inhibiting epithelial-mesenchymal transition, migration and invasion by binding to SDC1

Pancreatic cancer (PC) is the fourth most common cause of cancer‑related mortality in the industrialized world. Emerging evidence indicates that a variety of microRNAs (miRNAs or miRs) are involved in the development of PC. The aim of the present study was to elucidate the mechanisms through which miR‑494 affects the epithelial‑mesenchymal transition (EMT) and invasion of PC cells by binding to syndecan 1 (SDC1). PC tissues and pancreatitis tissues were collected, and the regulatory effects of miR‑494 on SDC1 were validated using bioinformatics analysis and a dual‑luciferase report gene assay. The cell line with the highest SDC1 expression was selected for use in the following experiments. The role of miR‑494 in EMT was assessed by measuring the expression of SDC1, E‑cadherin and vimentin. Cell proliferation was assessed using a cell counting kit (CCK)‑8 assay, migration was measured using a scratch test, invasion was assessed with a Transwell assay and apoptosis was detected by flow cytometry. Finally, a xenograft tumor model was constructed in nude mice to observe tumor growth in vivo. We found that SDC1 protein expression was significantly higher in the PC tissues. SDC1 was verified as a target gene of miR‑494. The SW1990 cell line was selected for use in further experiments as it had the lowest miR‑494 expression and the highest SDC1 expression. Our results also demonstrated that miR‑494 overexpression and SDC1 silencing significantly decreased the mRNA and protein expression of SDC1 and vimentin in SW1990 cells, while it increased E‑cadherin expression and apoptosis, and inhibited cell growth, migration, invasion and tumor growth. On the whole, the findings of this study demonstrated that miR‑494 is able to downregulate SDC1 expression, thereby inhibiting the progression of PC. These findings reveal a novel mechanism through which miR‑494 affects the development of PC and may thus provide a basis for the application of miR‑494 in pancreatic oncology.

Unbinding Kinetics of Syndecans by Single-Molecule Force Spectroscopy

Syndecans are transmembrane proteoglycans that, together with integrins, control cell interactions with extracellular matrix components. Despite structural similarities between all members of the syndecan family, their specific attachment to extracellular matrix proteins is defined by heparan and chondroitin chains. We postulate various unbinding kinetics for each type of single syndecan complex. Force spectroscopy data, recorded by atomic force microscope, were analyzed using two theoretical approaches describing force-induced unbinding, authored by Bell-Evans and Dudko-Hummer-Szabo. Our results reveal distinct unbinding pathways dependent on the syndecan family member. Syndecan-1 unbinds by passing over two energy barriers, inner and outer. Syndecan-4 unbinds by crossing over only one energy barrier. It has already been reported that both syndecans bear heparan chains that are structurally indistinguishable. Our finding reveals that unbinding of single syndecan complexes is family-member-dependent. Distinct unbinding pathways can be attributed to structural differences of heparan and chondroitin chains.

Syndecan-1 deficiency promotes tumor growth in a murine model of colitis-induced colon carcinoma

Syndecan-1 (Sdc1) is an important member of the cell surface heparan sulfate proteoglycan family, highly expressed by epithelial cells in adult organisms. Sdc1 is involved in the regulation of cell migration, cell-cell and cell-matrix interactions, growth-factor, chemokine and integrin activity, and implicated in inflammatory responses and tumorigenesis. Gastrointestinal tract represents an important anatomic site where loss of Sdc1 expression was reported both in inflammation and malignancy. However, the biological significance of Sdc1 in chronic colitis-associated tumorigenesis has not been elucidated. To the best of our knowledge, this study is the first to test the effects of Sdc1 loss on colorectal tumor development in inflammation-driven colon tumorigenesis. Utilizing a mouse model of colitis-related colon carcinoma induced by the carcinogen azoxymethane (AOM), followed by the inflammatory agent dextran sodium sulfate (DSS), we found that Sdc1 deficiency results in increased susceptibility to colitis-associated tumorigenesis. Importantly, colitis-associated tumors developed in Sdc1-defficient mice were characterized by increased local production of IL-6, activation of STAT3, as well as induction of several STAT3 target genes that act as important effectors of colonic tumorigenesis. Altogether, our results highlight a previously unknown effect of Sdc1 loss in progression of inflammation-associated cancer and suggest that decreased levels of Sdc1 may serve as an indicator of colon carcinoma progression in the setting of chronic inflammation.

Syndecans as Cell Surface Receptors in Cancer Biology. A Focus on their Interaction with PDZ Domain Proteins

Syndecans are transmembrane receptors with ectodomains that are modified by glycosaminoglycan chains. The ectodomains can interact with a wide variety of molecules, including growth factors, cytokines, proteinases, adhesion receptors, and extracellular matrix (ECM) components. The four syndecans in mammals are expressed in a development-, cell-type-, and tissue-specific manner and can function either as co-receptors with other cell surface receptors or as independent adhesion receptors that mediate cell signaling. They help regulate cell proliferation and migration, angiogenesis, cell/cell and cell/ECM adhesion, and they may participate in several key tumorigenesis processes. In some cancers, syndecan expression regulates tumor cell proliferation, adhesion, motility, and other functions, and may be a prognostic marker for tumor progression and patient survival. The short cytoplasmic tail is likely to be involved in these events through recruitment of signaling partners. In particular, the conserved carboxyl-terminal EFYA tetrapeptide sequence that is present in all syndecans binds to some PDZ domain-containing proteins that may function as scaffold proteins that recruit signaling and cytoskeletal proteins to the plasma membrane. There is growing interest in understanding these interactions at both the structural and biological levels, and recent findings show their high degree of complexity. Parameters that influence the recruitment of PDZ domain proteins by syndecans, such as binding specificity and affinity, are the focus of active investigations and are important for understanding regulatory mechanisms. Recent studies show that binding may be affected by post-translational events that influence regulatory mechanisms, such as phosphorylation within the syndecan cytoplasmic tail.

Prognostic and clinical significance of syndecan-1 in colorectal cancer: a meta-analysis

Background

Syndecan-1 plays a vital role in the suppression, transformation, and migration of several cancer types, including colorectal cancer (CRC). However, the prognostic and clinical significance of syndecan-1 in CRC remains conflicting. Therefore, we performed a meta-analysis to clarify this relationship.

Methods

A comprehensive literature search for relevant studies published up to December 2014 was performed using PubMed, EMBASE, and Ovid library database. The odds ratio (OR) and pooled hazard ratio (HR) with their 95 % confidence intervals (CI) were used to estimate the effects.

Results

Ten studies with 888 CRC patients were selected for evaluation. The results showed that syndecan-1 expression was lower in CRC tissue than in normal colorectal tissue (OR = 0.02, 95 % CI = 0.00–0.09), and lower in the advanced stage than in the early stage (OR = 2.24, 95 % CI = 1.14 − 4.42). Additionally, syndecan-1 expression was higher in well and moderately differentiated CRC than in poorly differentiated CRC (OR = 2.91, 95 % CI = 1.21–6.98); no significant difference was found in patients with or without lymph node metastasis (OR = 0.91, 95 % CI = 0.34–2.43) and distant metastasis (OR = 0.89, 95 % CI = 0.19-4.21). The pooled results showed that syndecan-1 expression was not associated with survival in CRC patients (HR = 0.93, 95 % CI = 0.86–1.01).

Conclusion

This meta-analysis indicated that loss of syndecan-1 expression is associated with CRC development, histological differentiation, and clinical stage, but not with lymph node metastasis and distant metastasis. In addition, these findings fail to support the prognostic significance of syndecan-1 in CRC.

Molecular and clinical profiles of syndecan-1 in solid and hematological cancer for prognosis and precision medicine

Syndecan-1 (SDC1, CD138) is a key cell surface adhesion molecule essential for maintaining cell morphology and interaction with the surrounding microenvironment. Deregulation of SDC1 contributes to cancer progression by promoting cell proliferation, metastasis, invasion and angiogenesis, and is associated with relapse through chemoresistance. SDC1 expression level is also associated with responses to chemotherapy and with prognosis in multiple solid and hematological cancers, including multiple myeloma and Hodgkin lymphoma. At the tissue level, the expression levels of SDC1 and the released extracellular domain of SDC1 correlate with tumor malignancy, phenotype, and metastatic potential for both solid and hematological tumors in a tissue-specific manner. The SDC1 expression profile varies among cancer types, but the differential expression signatures between normal and cancer cells in epithelial and stromal compartments are directly associated with aggressiveness of tumors and patient's clinical outcome and survival. Therefore, relevant biomarkers of SDC signaling may be useful for selecting patients that would most likely respond to a particular therapy at the time of diagnosis or perhaps for predicting relapse. In addition, the reciprocal expression signature of SDC between tumor epithelial and stromal compartments may have synergistic value for patient selection and the prediction of clinical outcome.

Syndecan-1 in Cancer: Implications for Cell Signaling, Differentiation, and Prognostication

Syndecan-1, a cell surface heparan sulfate proteoglycan, is critically involved in the differentiation and prognosis of various tumors. In this review, we highlight the synthesis, cellular interactions, and the signalling pathways regulated by syndecan-1. The basal syndecan-1 level is also crucial for understanding the sequential changes involving malignant transformation, tumor progression, and advanced or disseminated cancer stages. Moreover, we focus on the cellular localization of this proteoglycan as cell membrane anchored and/or shed, soluble syndecan-1 with stromal or nuclear accumulation and how this may carry different, highly tissue specific prognostic information for individual tumor types.

Proteoglycans as potential microenvironmental biomarkers for colon cancer

Glycosylation changes occur widely in colon tumours, suggesting glycosylated molecules as potential biomarkers for colon cancer diagnostics. In this study, proteoglycans (PGs) expression levels and their transcriptional patterns are investigated in human colon tumours in vivo and carcinoma cells in vitro. According to RT-PCR analysis, normal and cancer colon tissues expressed a specific set of PGs (syndecan-1, perlecan, decorin, biglycan, versican, NG2/CSPG4, serglycin, lumican, CD44), while the expression of glypican-1, brevican and aggrecan was almost undetectable. Overall transcriptional activity of the PGs in normal and cancer tissues was similar, although expression patterns were different. Expression of decorin and perlecan was down-regulated 2-fold in colon tumours, while biglycan and versican expression was significantly up-regulated (6-fold and 3-fold, respectively). Expression of collagen1A1 was also increased 6-fold in colon tumours. However, conventional HCT-116 colon carcinoma and AG2 colon cancer-initiating cells did not express biglycan and decorin and were versican-positive and -negative, respectively, demonstrating an extracellular origin of the PGs in cancer tissue. Selective expression of heparan sulfate (HS) proteoglycans syndecan-1 and perlecan in the AG2 colon cancer-initiating cell line suggests these PGs as potential biomarkers for cancer stem cells. Overall transcriptional activity of the HS biosynthetic system was similar in normal and cancer tissues, although significant up-regulation of extracellular sulfatases SULF1/2 argues for a possible distortion of HS sulfation patterns in colon tumours. Taken together, the obtained results suggest versican, biglycan, collagen1A1 and SULF1/2 expression as potential microenvironmental biomarkers and/or targets for colon cancer diagnostics and treatment.

Syndecan-1 expression is associated with tumor size and EGFR expression in colorectal carcinoma: a clinicopathological study of 230 cases

BACKGROUND

Syndecan-1 (SDC1) is reported to modulate several key processes of tumorigenesis and has variable expression in many cancers. To date, the cause of altered expression has not been elucidated. In this study, we compared SDC1 expression with various clinicopathological parameters and molecular markers to evaluate its clinical significance in colorectal carcinoma.

METHODS

We screened for SDC1 expression using immunohistochemistry in 230 surgical specimens of primary colorectal carcinoma from patients consecutively treated between 2008 and 2011 at Seoul St. Mary's Hospital, The Catholic University of Korea. The relationship between SDC1 expression and various clinicopathological parameters and molecular markers was analyzed.

RESULTS

The tumors were principally located in the left colon (71.3%) and rectum (33.5%). There were 216 (93.9%) adenocarcinomas, 10 (4.3%) mucinous adenocarcinomas, and 4 other tumors. Most of the carcinomas were pT3 (68.3%) and pT4 (22.2%). There was regional lymph node metastasis in 140 patients. SDC1 expression was identified in the cancer cells of 212 (96.8%) colon cancer cases. Of the SDC1-positive cases, 131 showed predominantly membranous immunopositivity, and 81 showed a predominantly cytoplasmic staining pattern. Mixed membranous and cytoplasmic staining was observed in 154 cases. In 93 cases, stromal SDC1 reactivity was noted. Epithelial SDC1 immunopositivity was significantly associated with tumor size (p=0.016) and epidermal growth factor receptor expression (p=0.006). However, it was not significantly correlated with lymph node metastasis, distant metastasis, lymphatic or vascular invasion, or KRAS mutation. In addition, stromal SDC1 immunopositivity was significantly associated with the male sex (p=0.018).

CONCLUSIONS

The expression profile of SDC1 may be of clinical value in colorectal cancer and may help in identifying aggressive forms of colorectal carcinoma. Further studies are needed in order to better understand the role of SDC1 in the progression and invasiveness of colorectal carcinoma.

Molecular concepts in the pathogenesis of ameloblastoma: implications for therapeutics

Ameloblastoma is a benign odontogenic neoplasm that may exhibit aggressive biological behavior as evidenced by its rapid growth and significance recurrence rates following initial surgical resection. Currently, the only therapy for ameloblastoma is surgical, and adjunctive treatment modalities are needed to mitigate tumor growth and to reduce the need for extensive and disfiguring surgeries. Many studies have identified markers expressed by ameloblastoma and these lend insight to our understanding of tumor progression. This review provides a summary of the specific molecular pathways implicated in tumor pathogenesis, including those involved in bone remodeling, apoptosis, cell signaling, and tumor suppression. Based on these data, we identify several prognostic or therapeutic markers that have been used successfully in the treatment of other neoplastic processes that may also have diagnostic and prognostic utility for ameloblastoma. Thus, it is important to determine which markers hold the greatest promise for clinical management of this benign neoplasm in order to improve treatment options, particularly in patients with aggressive forms of ameloblastoma.

Clinical implications in the shift of syndecan-1 expression from the cell membrane to the cytoplasm in bladder cancer

BACKGROUND

To determine the diagnostic and prognostic capability of urinary and tumoral syndecan-1 (SDC-1) levels in patients with cancer of the urinary bladder.

METHODS

SDC-1 levels were quantitated by enzyme-linked immunosorbent assay (ELISA) in 308 subjects (102 cancer subjects and 206 non-cancer subjects) to assess its diagnostic capabilities in voided urine. The performance of SDC-1 was evaluated using the area under the curve of a receiver operating characteristic curve. In addition, immunohistochemical (IHC) staining assessed SDC-1 protein expression in 193 bladder specimens (185 cancer subjects and 8 non-cancer subjects). Outcomes were correlated to SDC-1 levels.

RESULTS

Mean urinary levels of SDC-1 did not differ between the cancer subjects and the non-cancer subjects, however, the mean urinary levels of SDC-1 were reduced in high-grade compared to low-grade disease (p < 0.0001), and in muscle invasive bladder cancer (MIBC) compared to non-muscle invasive bladder cancer (NMIBC) (p = 0.005). Correspondingly, preliminary data note a shift from a membranous cellular localization of SDC-1 in normal tissue, low-grade tumors and NMIBC, to a distinctly cytoplasmic localization in high-grade tumors and MIBC was observed in tissue specimens.

CONCLUSION

Alone urinary SDC-1 may not be a diagnostic biomarker for bladder cancer, but its urinary levels and cellular localization were associated with the differentiation status of patients with bladder tumors. Further studies are warranted to define the potential role for SDC-1 in bladder cancer progression.

Prognostic significance of RSPO1, WNT1, P16, WT1, and SDC1 expressions in invasive ductal carcinoma of the breast

Background

To better understand the mechanisms of the SDC1 expression in invasive ductal carcinoma, we studied the correlations between SDC1 expression and related gene expressions (RSPO1, WNT1, WT1, and P16).

Methods

Using 100 cases of invasive ductal carcinoma tissue, we screened expressions of RSPO1, WNT1, WT1, P16, and SDC1 using immunohistochemistry. We analyzed the association between the immunoreactivities and clinicopathological parameters.

Results

WT1 expression was associated with tumor grade. RSPO1 expression was associated with progesterone receptor expression. Expressions of RSPO1, WT1, and P16 were significantly associated with disease-free survival. RSPO1 and P16 showed statistically significant hazard ratios. SDC1 ectodomain expression was significantly associated only with P16 expression. Immunoreactivity of SDC1 cytoplasmic domain was associated with WT1 and WNT1. However, WNT1 expression failed to show a significant association with disease-free survival.

Conclusions

RSPO1 and P16 immunoreactivity was found to be an independent prognostic indicator in invasive ductal cancer. Cytoplasmic expression of SDC1 is positively correlated with tumor-prone proteins (WT1 and WNT1) and membranous expression of SDC1 is positively correlated with the tumor suppressor (P16).

The role of syndecan-1 in cellular signaling and its effects on heparan sulfate biosynthesis in mesenchymal tumors

Proteoglycans (PGs) and in particular the syndecans are involved in the differentiation process across the epithelial-mesenchymal axis, principally through their ability to bind growth factors and modulate their downstream signaling. Malignant tumors have individual proteoglycan profiles, which are closely associated with their differentiation and biological behavior, mesenchymal tumors showing a different profile from that of epithelial tumors. Syndecan-1 is the main syndecan of epithelial malignancies, whereas in sarcomas its expression level is generally low, in accordance with their mesenchymal phenotype and highly malignant behavior. This proteoglycan is often overexpressed in adenocarcinoma cells, whereas mesothelioma and fibrosarcoma cells express syndecan-2 and syndecan-4 more abundantly. Increased expression of syndecan-1 in mesenchymal tumors changes the tumor cell morphology to an epithelioid direction whereas downregulation results in a change in shape from polygonal to spindle-like morphology. Although syndecan-1 plays major roles on the cell-surface, there are also intracellular functions, which are not very well studied. On the functional level, syndecan-1 affects mesenchymal tumor cell proliferation, adhesion, migration and motility, and the effect varies with the different domains of the core protein. Syndecan-1 may exert stimulatory or inhibitory effects, depending on the concentration of various mitogens, enzymes, and signaling molecules, the ratio between the shed and membrane-associated syndecan-1 and histological grade of the tumour. Growth factor signaling seems to be delicately controlled by regulatory loops involving the syndecan expression levels and their sulfation patterns. Overexpression of syndecan-1 modulates the biosynthesis and sulfation of heparan sulfate and it also affects the expression of other PGs. On transcriptomic level, syndecan-1 modulation results in profound effects on genes involved in regulation of cell growth.

Novel genes and pathways modulated by syndecan-1: implications for the proliferation and cell-cycle regulation of malignant mesothelioma cells

Malignant pleural mesothelioma is a highly malignant tumor, originating from mesothelial cells of the serous cavities. In mesothelioma the expression of syndecan-1 correlates to epithelioid morphology and inhibition of growth and migration. Our previous data suggest a complex role of syndecan-1 in mesothelioma cell proliferation although the exact underlying molecular mechanisms are not completely elucidated. The aim of this study is therefore to disclose critical genes and pathways affected by syndecan-1 in mesothelioma; in order to better understand its importance for tumor cell growth and proliferation. We modulated the expression of syndecan-1 in a human mesothelioma cell line via both overexpression and silencing, and followed the transcriptomic responses with microarray analysis. To project the transcriptome analysis on the full-dimensional picture of cellular regulation, we applied pathway analysis using Ingenuity Pathway Analysis (IPA) and a novel method of network enrichment analysis (NEA) which elucidated signaling relations between differentially expressed genes and pathways acting via various molecular mechanisms. Syndecan-1 overexpression had profound effects on genes involved in regulation of cell growth, cell cycle progression, adhesion, migration and extracellular matrix organization. In particular, expression of several growth factors, interleukins, and enzymes of importance for heparan sulfate sulfation pattern, extracellular matrix proteins and proteoglycans were significantly altered. Syndecan-1 silencing had less powerful effect on the transcriptome compared to overexpression, which can be explained by the already low initial syndecan-1 level of these cells. Nevertheless, 14 genes showed response to both up- and downregulation of syndecan-1. The "cytokine - cytokine-receptor interaction", the TGF-β, EGF, VEGF and ERK/MAPK pathways were enriched in both experimental settings. Most strikingly, nearly all analyzed pathways related to cell cycle were enriched after syndecan-1 silencing and depleted after syndecan-1 overexpression. Syndecan-1 regulates proliferation in a highly complex way, although the exact contribution of the altered pathways necessitates further functional studies.

Novel genes and pathways modulated by syndecan-1: implications for the proliferation and cell-cycle regulation of malignant mesothelioma cells

Malignant pleural mesothelioma is a highly malignant tumor, originating from mesothelial cells of the serous cavities. In mesothelioma the expression of syndecan-1 correlates to epithelioid morphology and inhibition of growth and migration. Our previous data suggest a complex role of syndecan-1 in mesothelioma cell proliferation although the exact underlying molecular mechanisms are not completely elucidated. The aim of this study is therefore to disclose critical genes and pathways affected by syndecan-1 in mesothelioma; in order to better understand its importance for tumor cell growth and proliferation. We modulated the expression of syndecan-1 in a human mesothelioma cell line via both overexpression and silencing, and followed the transcriptomic responses with microarray analysis. To project the transcriptome analysis on the full-dimensional picture of cellular regulation, we applied pathway analysis using Ingenuity Pathway Analysis (IPA) and a novel method of network enrichment analysis (NEA) which elucidated signaling relations between differentially expressed genes and pathways acting via various molecular mechanisms. Syndecan-1 overexpression had profound effects on genes involved in regulation of cell growth, cell cycle progression, adhesion, migration and extracellular matrix organization. In particular, expression of several growth factors, interleukins, and enzymes of importance for heparan sulfate sulfation pattern, extracellular matrix proteins and proteoglycans were significantly altered. Syndecan-1 silencing had less powerful effect on the transcriptome compared to overexpression, which can be explained by the already low initial syndecan-1 level of these cells. Nevertheless, 14 genes showed response to both up- and downregulation of syndecan-1. The "cytokine - cytokine-receptor interaction", the TGF-β, EGF, VEGF and ERK/MAPK pathways were enriched in both experimental settings. Most strikingly, nearly all analyzed pathways related to cell cycle were enriched after syndecan-1 silencing and depleted after syndecan-1 overexpression. Syndecan-1 regulates proliferation in a highly complex way, although the exact contribution of the altered pathways necessitates further functional studies.

Syndecan 1 plays a novel role in enteral glutamine's gut-protective effects of the postischemic gut

Syndecan 1 is the predominant heparan sulfate proteoglycan found on the surface of epithelial cells and, like glutamine, is essential in maintaining the intestinal epithelial barrier. We therefore hypothesized that loss of epithelial syndecan 1 would abrogate the gut-protective effects of enteral glutamine. Both an in vitro and in vivo model of gut ischemia-reperfusion (IR) was utilized. In vitro, intestinal epithelial cells underwent hypoxia-reoxygenation to mimic gut IR with 2 mM (physiologic) or 10 mM glutamine supplementation. Permeability, caspase activity, cell growth, and cell surface and shed syndecan 1 were assessed. In vivo, wild-type and syndecan 1 knockout (KO) mice received ± enteral glutamine followed by gut IR. Intestinal injury was assessed by fluorescent dye clearance and histopathology, permeability as mucosal-to-serosal clearance ex vivo in everted sacs, and inflammation by myeloperoxidase (MPO) activity. In an in vitro model of gut IR, glutamine supplementation reduced epithelial cell permeability and apoptosis and enhanced cell growth. Shed syndecan 1 was reduced by glutamine without an increase in syndecan 1 mRNA. In vivo, intestinal permeability, inflammation, and injury were increased after gut IR in wild-type mice and further increased in syndecan 1 KO mice. Glutamine's attenuation of IR-induced intestinal hyperpermeability, inflammation, and injury was abolished in syndecan 1 KO mice. These results suggest that syndecan 1 plays a novel role in the protective effects of enteral glutamine in the postischemic gut.

Breast and ovarian cancers: a survey and possible roles for the cell surface heparan sulfate proteoglycans

Tumor markers are widely used in pathology not only for diagnostic purposes but also to assess the prognosis and to predict the treatment of the tumor. Because tumor marker levels may change over time, it is important to get a better understanding of the molecular changes during tumor progression. Occurrence of breast and ovarian cancer is high in older women. Common known risk factors of developing these cancers in addition to age are not having children or having children at a later age, the use of hormone replacement therapy, and mutations in certain genes. In addition, women with a history of breast cancer may also develop ovarian cancer. Here, the authors review the different tumor markers of breast and ovarian carcinoma and discuss the expression, mutations, and possible roles of cell surface heparan sulfate proteoglycans during tumorigenesis of these carcinomas. The focus is on two groups of proteoglycans, the transmembrane syndecans and the lipid-anchored glypicans. Both families of proteoglycans have been implicated in cellular responses to growth factors and morphogens, including many now associated with tumor progression.

Molecular functions of syndecan-1 in disease

Syndecan-1 is a cell surface heparan sulfate proteoglycan that binds to many mediators of disease pathogenesis. Through these molecular interactions, syndecan-1 can modulate leukocyte recruitment, cancer cell proliferation and invasion, angiogenesis, microbial attachment and entry, host defense mechanisms, and matrix remodeling. The significance of syndecan-1 interactions in disease is underscored by the striking pathological phenotypes seen in the syndecan-1 null mice when they are challenged with disease-instigating agents or conditions. This review discusses the key molecular functions of syndecan-1 in modulating the onset, progression, and resolution of inflammatory diseases, cancer, and infection.

Proteoglycans in health and disease: novel roles for proteoglycans in malignancy and their pharmacological targeting

The expression of proteoglycans (PGs), essential macromolecules of the tumor microenvironment, is markedly altered during malignant transformation and tumor progression. Synthesis of stromal PGs is affected by factors secreted by cancer cells and the unique tumor-modified extracellular matrix may either facilitate or counteract the growth of solid tumors. The emerging theme is that this dual activity has intrinsic tissue specificity. Matrix-accumulated PGs, such as versican, perlecan and small leucine-rich PGs, affect cancer cell signaling, growth and survival, cell adhesion, migration and angiogenesis. Furthermore, expression of cell-surface-associated PGs, such as syndecans and glypicans, is also modulated in both tumor and stromal cells. Cell-surface-associated PGs bind various factors that are involved in cell signaling, thereby affecting cell proliferation, adhesion and motility. An important mechanism of action is offered by a proteolytic processing of cell-surface PGs known as ectodomain shedding of syndecans; this facilitates cancer and endothelial cell motility, protects matrix proteases and provides a chemotactic gradient of mitogens. However, syndecans on stromal cells may be important for stromal cell/cancer cell interplay and may promote stromal cell proliferation, migration and angiogenesis. Finally, abnormal PG expression in cancer and stromal cells may serve as a biomarker for tumor progression and patient survival. Enhanced understanding of the regulation of PG metabolism and the involvement of PGs in cancer may offer a novel approach to cancer therapy by targeting the tumor microenvironment. In this minireview, the implication of PGs in cancer development and progression, as well as their pharmacological targeting in malignancy, are presented and discussed.

Heparanase-2, syndecan-1, and extracellular matrix remodeling in colorectal carcinoma

AIM

To propose a quantitative method to detect heparanase-2 (HPA2) and syndecan-1 (Syn-1) using immunohistochemistry in colorectal (colon and rectal) carcinomas compared with nonneoplastic tissues and evaluate the possible role of these molecules in tumor development and extracellular remodeling.

METHODS

Cytoplasmic staining of HPA2 and Syn-1 was obtained by standard immunohistochemical reactions in 50 colorectal carcinoma and 20 nonneoplastic large bowels tissues. An image system was used to quantify the immunoexpression by digital computer-assisted method (Matos et al. 2006). The cutoff point for the immunohistochemistry variable was defined by sensibility and specificity curves. Statistical analysis was performed using SPSS version 13.0.

RESULTS

HPA2 was over-expressed in colorectal cancer (131.1+/-24.9 o.u./microm) when compared with nonneoplastic tissues (27.9+/-12.2 o.u./microm) (P<0.0001). However, an opposite correlation was observed between Syn-1 and tumor presence, where colorectal tissues expressed lower Syn-1 proteoglycan compared with nonneoplastic tissues, respectively (39.2+/-17.8 o.u./microm) and (102.2+/-25.2 o.u./microm) (P<0.0001).

CONCLUSION

A methodology with high sensitivity and specificity is proposed with a cutoff value for HPA2 and Syn-1 in the immunohistochemistry assay to define the presence of tumor. It was demonstrated for the first time in the literature that HPA2 is over-expressed in colorectal carcinoma tissues compared with nonneoplastic tissues. HPA2 over-expression could be possibly related to Syn-1 shedding despite the fact that HPA2 does not present enzymatic activity as HPA1.

Association of loss of epithelial syndecan-1 with stage and local metastasis of colorectal adenocarcinomas: an immunohistochemical study of clinically annotated tumors

Background

Syndecan-1 is a transmembrane proteoglycan with important roles in cell-cell and cell-extracellular matrix adhesion and as a growth factor co-receptor. Syndecan-1 is highly expressed by normal epithelial cells and loss of expression has been associated with epithelial-mesenchymal transition and the transformed phenotype. Loss of epithelial syndecan-1 has been reported in human colorectal adenocarcinomas, but whether this has prognostic significance remains undecided. Here we have examined syndecan-1 expression and its potential prognostic value with reference to a clinically annotated tissue microarray for human colon adenocarcinomas.

Methods

Syndecan-1 expression was examined by immunohistochemistry of a tissue microarray containing cores from 158 colorectal adenocarcinomas and 15 adenomas linked to a Cleveland Clinic, IRB-approved database with a mean clinical follow-up of 38 months. The Kaplan-Meier method was used to analyze the relationship between syndecan-1 expression and patient survival. Potential correlations between syndecan-1 expression and the candidate prognostic biomarker fascin were examined.

Results

Syndecan-1 is expressed at the basolateral borders of normal colonic epithelial cells. On adenocarcinoma cells, syndecan-1 was present around cell membranes and in cytoplasm. In 87% of adenocarcinomas, syndecan-1 was decreased or absent; only 13% of patients had stained for syndecan-1 on more than 75% of tumor cells. Decreased syndecan-1 correlated with a higher TNM stage and lymph node metastasis and was more common in males (p = 0.042), but was not associated with age, tumor location or Ki67 index. Reduced tumor syndecan-1 staining also correlated with upregulation of stromal fascin (p = 0.016). Stromal syndecan-1 was observed in 16.6% of tumors. There was no difference in survival between patients with low or high levels of either tumor or stromal syndecan-1.

Conclusion

Syndecan-1 immunoreactivity was decreased in the majority of human colon adenocarcinomas in correlation with TNM stage and metastasis to local lymph nodes. In a small fraction of adenocarcinomas, syndecan-1 was upregulated in the local stroma. Syndecan-1 expression status did not correlate with patient survival outcomes. Combined analysis of syndecan-1 in relation to a potential prognostic biomarker, fascin, identified that loss of tumor syndecan-1 correlated significantly with strong stromal fascin staining.

Prognostic impact of syndecan-1 expression in invasive ductal breast carcinomas

Carcinoma cells lack syndecan-1 expression when they are transiting from an epithelial to a less-differentiated mesenchymal phenotype (epithelial–mesenchymal transition, EMT). Furthermore, a shift of syndecan-1 expression from malignant epithelial cells to reactive stromal cells has also been observed during progression of many carcinomas. Finally, epithelial and/or stromal syndecan-1 expression is of prognostic value in many carcinomas. Because recent results are contradictory in breast carcinomas, we have re-evaluated the prognostic significance of syndecan-1 expression in a cohort of 80 patients with invasive ductal breast carcinomas. The tumours from 80 patients diagnosed with invasive ductal breast carcinomas were used to construct a tissue microarray, which was stained with syndecan-1 by immunohistochemistry. We correlated syndecan-1 expression with clinicopathologic parameters and relapse-free survival (RFS). Exclusive epithelial expression of syndecan-1 is observed in 61.25% of the patients, whereas exclusive stromal expression is observed in 30% of the patients. Only 8.75% of the patients had both stromal and epithelial expressions of syndecan-1. A significant correlation was found between the loss of syndecan-1 epithelial expression and the syndecan-1 stromal expression with high grade of malignancy (P=0.011). The loss of syndecan-1 epithelial expression is correlated with RFS (P=0.001). Using multivariate Cox analysis, loss of epithelial syndecan-1 expression was the only prognostic indicator (P<0.001). We concluded that the loss of syndecan-1 epithelial expression was of strong prognostic value in breast carcinomas.

Expression of Extracellular Matrix Proteins in Ovarian Serous Tumors

The aims of this study were to perform a comprehensive expression analysis of the genes encoding extracellular matrix proteins and to investigate the expression pattern in one of these proteins, syndecan 1, in normal ovarian epithelium as well as benign and malignant ovarian serous tumors. Gene expression of 16 different extracellular matrix proteins was analyzed in ovarian serous tumors based on serial analysis of gene expression database. Semiquantitative reverse transcription-polymerase chain reaction was used to validate the serial analysis of gene expression result from each gene. As compared with normal ovarian surface epithelium, we found overexpression of syndecan 1, collagen type IV alpha 2, elastin microfibril interfase located protein 1, and laminin 5 in ovarian serous carcinomas. Syndecan 1 was selected for further study as it has not been well characterized in ovarian cancer and the syndecan 1 antibody was available for immunohistochemistry. Using a syndecan 1-specific monoclonal antibody, we demonstrated that syndecan 1 was expressed in 30.4% of high-grade serous carcinomas, 29.7% of low-grade carcinomas and serous borderline tumors, but none of benign serous cystadenomas and ovarian surface epithelium. Although both high-grade and low-grade serous carcinomas had a similar percentage of syndecan 1-positive cases, the immunointensity in high-grade carcinoma was significantly higher than that in low-grade carcinomas and serous borderline tumors (P = 0.007). In summary, ovarian carcinomas exhibit up-regulated expression of several extracellular matrix proteins, and syndecan 1 represents a novel tumor-associated marker in ovarian serous carcinomas.

The role of syndecans in disease and wound healing

Syndecans are a family of transmembrane heparan sulfate proteoglycans widely expressed in both developing and adult tissues. Until recently, their role in pathogenesis was largely unexplored. In this review, we discuss the reported involvement of syndecans in human cancers, infectious diseases, obesity, wound healing and angiogenesis. In some cancers, syndecan expression has been shown to regulate tumor cell function (e.g. proliferation, adhesion, and motility) and serve as a prognostic marker for tumor progression and patient survival. The ectodomains and heparan sulfate glycosaminoglycan chains of syndecans can also act as receptors/co-receptors for some bacterial and viral pathogens, mediating infection. In addition, syndecans bind to obesity-related factors and regulate their signaling, in turn modulating food consumption and weight balance. In vivo animal models of tissue injury and in vitro data also implicate syndecans in processes necessary for wound healing, including fibroblast and endothelial proliferation, cell motility, angiogenesis, and extracellular matrix organization. These new insights into the involvement of syndecans in disease and tissue repair coupled with the emergence of syndecan-specific molecular tools may lead to novel therapies for a variety of human diseases.