High syndecan-1 expression in breast carcinoma is related to an aggressive phenotype and to poorer prognosis

Targeting of syndecan-1 by micro-ribonucleic acid miR-10b modulates invasiveness of endometriotic cells via dysregulation of the proteolytic milieu and interleukin-6 secretion

OBJECTIVE

To study the function of syndecan-1 (SDC1) and its potential regulator miR-10b in endometriosis.

DESIGN

Experimental laboratory study.

SETTING

University medical center.

PATIENT(S)

Not applicable.

INTERVENTION(S)

The human endometriotic cell line 12Z was transiently transfected with SDC1 small interfering RNA or miR-10b precursors and investigated for changes in cell behavior and gene expression. 12Z and primary eutopic endometrial stroma cells of two American Society for Reproductive Medicine class III endometriosis patients were transfected with miR-10b precursors to investigate posttranscriptional regulation of SDC1.

MAIN OUTCOME MEASURE(S)

Quantitative polymerase chain reaction, Western blotting, flow cytometry, 3' untranslated region luciferase assays, and zymography were used to measure miR-10b-dependent targeting of SDC1 and SDC1-dependent expression changes of proteases and interleukin-6. Altered cell behavior was monitored by Matrigel invasion assays, cell viability assays, and mitogen-activated protein kinase activation blots.

RESULT(S)

Knockdown of SDC1 inhibited Matrigel invasiveness by >60% but did not affect cell viability. Interleukin-6 secretion, matrix metalloproteinase-9 expression, and matrix metalloproteinase-2 activity were reduced, whereas plasminogen activator inhibitor-1 protein expression was up-regulated. miR-10b overexpression significantly down-regulated SDC1, reduced Matrigel invasiveness by 20% and cell viability by 14%, and decreased mitogen-activated protein kinase activation in response to hepatocyte growth factor.

CONCLUSION(S)

Syndecan-1, a target of miR-10b, inhibits epithelial endometriotic cell invasiveness through down-regulation of metalloproteinase activity and interleukin-6.

Current and emerging quantitative magnetic resonance imaging methods for assessing and predicting the response of breast cancer to neoadjuvant therapy

Reliable early assessment of breast cancer response to neoadjuvant therapy (NAT) would provide considerable benefit to patient care and ongoing research efforts, and demand for accurate and noninvasive early-response biomarkers is likely to increase. Response assessment techniques derived from quantitative magnetic resonance imaging (MRI) hold great potential for integration into treatment algorithms and clinical trials. Quantitative MRI techniques already available for assessing breast cancer response to neoadjuvant therapy include lesion size measurement, dynamic contrast-enhanced MRI, diffusion-weighted MRI, and proton magnetic resonance spectroscopy. Emerging yet promising techniques include magnetization transfer MRI, chemical exchange saturation transfer MRI, magnetic resonance elastography, and hyperpolarized MR. Translating and incorporating these techniques into the clinical setting will require close attention to statistical validation methods, standardization and reproducibility of technique, and scanning protocol design.

Targeting of syndecan-1 by microRNA miR-10b promotes breast cancer cell motility and invasiveness via a Rho-GTPase- and E-cadherin-dependent mechanism

microRNAs are small endogenous noncoding RNAs, which post-transcriptionally regulate gene expression. In breast cancer, overexpression of the transmembrane heparan sulfate proteoglycan syndecan-1, a predicted target of the oncomiR miR-10b, correlates with poor clinical outcome. To investigate the potential functional relationship of miR-10b and syndecan-1, MDA-MB-231 and MCF-7 breast cancer cells were transiently transfected with pre-miR-10b, syndecan-1 siRNA or control reagents, respectively. Altered cell behavior was monitored by proliferation, migration and invasion chamber assays, and time-lapse video microscopy. miR-10b overexpression induced post-transcriptional downregulation of syndecan-1, as demonstrated by quantitative real-time PCR (qPCR), flow cytometry, and 3'UTR luciferase assays, resulting in increased cancer cell migration and matrigel invasiveness. Syndecan-1 silencing generated a copy of this phenotype. Adhesion to fibronectin and laminin and basal cell proliferation was increased. Syndecan-1 coimmunoprecipitated with focal adhesion kinase, which showed increased activation upon syndecan-1 depletion. Affymetrix screening and confirmatory qPCR and Western blotting analysis of syndecan-1-deficient cells revealed upregulation of ATF-2, COX-2, cadherin-11, vinculin, actin γ 2, MYL9, transgelin-1, RhoA/C, matrix metalloproteinase 2 (MMP2) and heparanase, and downregulation of AML1/RUNX1, E-cadherin, CLDN1, p21WAF/CIP, cyclin-dependent kinase 6, TLR-4, PAI1/2, Collagen1alpha1, JHDM1D, Mpp4, MMP9, matrilin-2 and ANXA3/A10. Video microscopy demonstrated massively increased Rho kinase-dependent motility of syndecan-1-depleted cells, which displayed increased filopodia formation. We conclude that syndecan-1 is a novel target of the oncomiR miR-10b. Rho-GTPase-dependent modulation of cytoskeletal function and downregulation of E-cadherin expression are identified as relevant effectors of the miR-10b-syndecan-1 axis, which emerges as a promising target for the development of new therapeutic approaches for breast cancer.

Low expression of IGFBP7 is associated with poor outcome of pancreatic ductal adenocarcinoma

BACKGROUND

Insulin-like growth factor binding protein 7(IGFBP7) has been implicated as a potential tumor suppressor in various human cancers, although the role of IGFBP7 in pancreatic ductal adenocarcinoma (PDAC) is still unknown. We investigated the expression pattern and clinical significance of IGFBP7 in human PDAC.

METHODS

IGFBP7 expression was evaluated by immunohistochemistry in 190 patients with PDAC who underwent surgical tumor resection. Expression of IGFBP7 was correlated with that of p53 and Ki-67, clinicopathologic features. We also evaluated overall survival (OS) according to expression of IGFBP7 by Kaplan-Meier and Cox regression analyses.

RESULTS

IGFBP7 expression was significantly downregulated in pancreatic cancer tissues compared with adjacent normal pancreas (P < 0.001) and was inversely associated with Ki-67 expression (r = -0.284, P < 0.001). No significant relationships were found for clinicopathologic features, such as diameter of tumor, node status, grade, and stage. Importantly, low expression of IGFBP7 was associated with poor OS, and this was also significant in multivariate Cox regression analysis (hazard ratio [HR], 1.38; 95 % confidence interval [95 % CI], 1.00-1.91; P = 0.05).

CONCLUSIONS

We demonstrate for the first time that IGFBP7 is downregulated in pancreatic cancer, and low expression of IGFBP7 is correlated with increased proliferation and poor postoperative survival. IGFBP7 may be a tumor suppressor in PDAC.

Polyunsaturated fatty acid metabolism in prostate cancer

Polyunsaturated fatty acids (PUFA) play important roles in the normal physiology and in pathological states including inflammation and cancer. While much is known about the biosynthesis and biological activities of eicosanoids derived from ω6 PUFA, our understanding of the corresponding ω3 series lipid mediators is still rudimentary. The purpose of this review is not to offer a comprehensive summary of the literature on fatty acids in prostate cancer but rather to highlight some of the areas where key questions remain to be addressed. These include substrate preference and polymorphic variants of enzymes involved in the metabolism of PUFA, the relationship between de novo lipid synthesis and dietary lipid metabolism pathways, the contribution of cyclooxygenases and lipoxygenases as well as terminal synthases and prostanoid receptors in prostate cancer, and the potential role of PUFA in angiogenesis and cell surface receptor signaling.

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.

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.

Syndecan-1 antigen, a promising new target for triple-negative breast cancer immuno-PET and radioimmunotherapy. A preclinical study on MDA-MB-468 xenograft tumors

BACKGROUND

Overexpression of syndecan-1 (CD138) in breast carcinoma correlates with a poor prognosis and an aggressive phenotype. The objective of this study was to evaluate the potential of targeting CD138 by immuno-PET imaging and radioimmunotherapy (RIT) using the antihuman syndecan-1 B-B4 mAb radiolabeled with either 124I or 131I in nude mice engrafted with the triple-negative MDA-MB-468 breast cancer cell line.

METHOD

The immunoreactivity of 125I-B-B4 (80%) was determined, and the affinity of 125I-B-B4 and the expression of CD138 on MDA-MB-468 was measured in vitro by Scatchard analysis. CD138 expression on established tumors was confirmed by immunohistochemistry. A biodistribution study was performed in mice with subcutaneous MDA-MB-468 and 125I-B-B4 at 4, 24, 48, 72, and 96 h after injection and compared with an isotype-matched control. Tumor uptake of B-B4 was evaluated in vivo by immuno-PET imaging using the 124I-B-B4 mAb. The maximum tolerated dose (MTD) was determined from mice treated with 131I-B-B4 and the RIT efficacy evaluated.

RESULTS

125I-B-B4 affinity was in the nanomolar range (Kd = 4.39 ± 1.10 nM). CD138 expression on MDA-MB-468 cells was quite low (Bmax = 1.19 × 104 ± 9.27 × 102 epitopes/cell) but all expressed CD138 in vivo as determined by immunohistochemistry. The tumor uptake of 125I-B-B4 peaked at 14% injected dose (ID) per gram at 24 h and was higher than that of the isotype-matched control mAb (5% ID per gram at 24 h). Immuno-PET performed with 124I-B-B4 on tumor-bearing mice confirmed the specificity of B-B4 uptake and its retention within the tumor. The MTD was reached at 22.2 MBq. All mice treated with RIT (n = 8) as a single treatment at the MTD experienced a partial (n = 3) or complete (n = 5) response, with three of them remaining tumor-free 95 days after treatment.

CONCLUSION

These results demonstrate that RIT with 131I-B-B4 could be considered for the treatment of metastatic triple-negative breast cancer that cannot benefit from hormone therapy or anti-Her2/neu immunotherapy. Immuno-PET for visualizing CD138-expressing tumors with 124I-B-B4 reinforces the interest of this mAb for diagnosis and quantitative imaging.

Low expression of aldehyde dehydrogenase 1A1 (ALDH1A1) is a prognostic marker for poor survival in pancreatic cancer

BACKGROUND

Aldehyde dehydrogenase 1 (ALDH1) has been characterised as a cancer stem cell marker in different types of tumours. Additionally, it plays a pivotal role in gene regulation and endows tumour cells with augmented chemoresistance. Recently, ALDH1A1 has been described as a prognostic marker in a pancreatic cancer tissue microarray. The aim of this study was to reevaluate the expression of ALDH1A1 as a prognostic marker on whole-mount tissue sections.

METHODS

Real-time-quantitative-PCR (qRT-PCR) and Western blotting were used to evaluate the expression profile of ALDH1A1 in seven pancreatic cancer cell lines and one non-malignant pancreatic cell line. Immunostaining against ALDH1A1 and Ki-67 was performed on paraffin-embedded samples from 97 patients with pancreatic cancer. The immunohistochemical results were correlated to histopathological and clinical data.

RESULTS

qRT-PCR and Western blotting revealed a different expression pattern of ALDH1A1 in different malignant and non-malignant pancreatic cell lines. Immunohistochemical analysis demonstrated that ALDH1A1 was confined to the cellular cytoplasm and occurred in 72 cases (74%), whereas it was negative in 25 cases (26%). High expression of ALDH1A1 was significantly correlated to an increased proliferation rate (Spearman correlation, p = 0.01). Univariate and multivariate analyses showed that decreased expression of ALDH1A1 is an independent adverse prognostic factor for overall survival.

CONCLUSIONS

Immunohistochemical analysis on whole-mount tissue slides revealed that ALDH1A1 is more abundantly expressed in pancreatic cancer than initially reported by a tissue microarray analysis. Moreover, high expression of ALDH1A1 correlated significantly with the proliferation of tumour cells. Intriguingly, this study is the first which identifies low expression of ALDH1A1 as an independent adverse prognostic marker for overall survival in pancreatic cancer.

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.

Proteoglycans in cancer biology, tumour microenvironment and angiogenesis

Proteoglycans, key molecular effectors of cell surface and pericellular microenvironments, perform multiple functions in cancer and angiogenesis by virtue of their polyhedric nature and their ability to interact with both ligands and receptors that regulate neoplastic growth and neovascularization. Some proteoglycans such as perlecan, have pro- and anti-angiogenic activities, whereas other proteoglycans, such as syndecans and glypicans, can also directly affect cancer growth by modulating key signalling pathways. The bioactivity of these proteoglycans is further modulated by several classes of enzymes within the tumour microenvironment: (i) sheddases that cleave transmembrane or cell-associated syndecans and glypicans, (ii) various proteinases that cleave the protein core of pericellular proteoglycans and (iii) heparanases and endosulfatases which modify the structure and bioactivity of various heparan sulphate proteoglycans and their bound growth factors. In contrast, some of the small leucine-rich proteoglycans, such as decorin and lumican, act as tumour repressors by physically antagonizing receptor tyrosine kinases including the epidermal growth factor and the Met receptors or integrin receptors thereby evoking anti-survival and pro-apoptotic pathways. In this review we will critically assess the expanding repertoire of molecular interactions attributed to various proteoglycans and will discuss novel proteoglycan functions modulating cancer progression, invasion and metastasis and how these factors regulate the tumour microenvironment.

Syndecan-1 and syndecan-4 are independent indicators in breast carcinoma

Syndecan proteoglycans may be key regulators of tumor invasion and metastasis because this four-member family of transmembrane receptors regulates cell adhesion, proliferation, and differentiation. Their expression can also serve as prognostic markers. In breast carcinomas, syndecan-1 overexpression correlates with poor prognosis and aggressive phenotype. Syndecan-4 is expressed in most breast carcinoma cell lines, but its role in malignancy is unclear. A possible relationship between syndecan-1 and syndecan-4 expression and established prognostic factors in breast carcinomas was examined. Duplicate samples of 114 benign and malignant breast disease cases were stained for the two syndecans. Clinicopathological information was available for all cases. Syndecan-1 was detected in 72.8% of cases, with significant association between its expression and histological tumor type (p<0.05) and high grade tumors (p<0.05). Syndecan-4 was expressed in 66.7% of cases; expression correlated significantly with positive estrogen (p<0.01) and progesterone (p<0.01) receptor status. Independent expression of the two syndecans was noted from an analysis of single and double positive cases. There was a statistical relationship between syndecan-1 presence in high-grade tumors and absence of syndecan-4, whereas syndecan-4 presence in cases positive for estrogen and progesterone receptor associated with syndecan-1 absence. These syndecans may, therefore, have distinct roles in regulating breast carcinoma cell behavior.

Syndecan-1 and -4 differentially regulate oncogenic K-ras dependent cell invasion into collagen through α2β1 integrin and MT1-MMP

Syndecans function as co-receptors for integrins on different matrixes. Recently, syndecan-1 has been shown to be important for α2β1 integrin-mediated adhesion to collagen in tumor cells by regulating cell adhesion and migration on two-dimensional collagen. However, the function of syndecans in supporting α2β1 integrin interactions with three-dimensional (3D) collagen is less well studied. Using loss-of-function and overexpression experiments we show that in 3D collagen syndecan-4 supports α2β1-mediated collagen matrix contraction. Cell invasion through type I collagen containing 3D extracellular matrix (ECM) is driven by α2β1 integrin and membrane type-1 matrix metalloproteinase (MT1-MMP). Here we show that mutational activation of K-ras correlates with increased expression of α2β1 integrin, MT1-MMP, syndecan-1, and syndecan-4. While K-ras-induced α2β1 integrin and MT1-MMP are positive regulators of invasion, silencing and overexpression of syndecans demonstrate that these proteins inhibit cell invasion into collagen. Taken together, these data demonstrate the existence of a complex interplay between integrin α2β1, MT1-MMP, and syndecans in the invasion of K-ras mutant cells in 3D collagen that may represent a mechanism by which tumor cells become more invasive and metastatic.

Syndecan-1-dependent suppression of PDK1/Akt/bad signaling by docosahexaenoic acid induces apoptosis in prostate cancer

Evidence indicates that diets enriched in n-3 polyunsaturated fatty acids (n-3 PUFAs) reduce the risk of prostate cancer, but biochemical mechanisms are unclear. Syndecan-1 (SDC-1), a transmembrane heparan sulfate proteoglycan, supports the integrity of the epithelial compartment. In tumor cells of epithelial lineage, SDC-1 is generally downregulated. This may result in perturbation of homeostasis and lead to progression of malignancy. Our studies have shown that the n-3 PUFA species, docosahexaenoic acid (DHA), increases SDC-1 expression in prostate tissues of Pten knockout (Pten(P-/-)) mice/cells and human prostate cancer cells. We have now determined that DHA-mediated up-regulation of SDC-1 induces apoptosis. Bovine serum albumin-bound DHA and exogenous human recombinant SDC-1 ecotodomain were delivered to PC3 and LNCaP cells in the presence or absence of SDC-1 small interfering (si)RNA. In the presence of control siRNA, both DHA and SDC-1 ectodomain induced apoptosis, whereas SDC-1 silencing blocked DHA-induced but not SDC-1 ectodomain-induced apoptosis. Downstream effectors of SDC-1 signaling linked to n-3 PUFA-induced apoptosis involved the 3'-phosphoinositide-dependent kinase 1 (PDK1)/Akt/Bad integrating network. A diet enriched in n-3 PUFA decreased phosphorylation of PDK1, Akt (T308), and Bad in prostates of Pten(P-/-) mice. Similar results were observed in human prostate cancer cells in response to DHA and SDC-1 ectodomain. The effect of DHA on PDK1/Akt/Bad signaling was abrogated by SDC-1 siRNA. These findings define a mechanism by which SDC-1-dependent suppression of phosphorylation of PDK1/Akt/Bad mediates n-3 PUFA-induced apoptosis in prostate cancer.

Syndecan-1 overexpression promotes tumor growth and angiogenesis in an endometrial cancer xenograft model

OBJECTIVES

Upregulation of syndecan-1, a member of the transmembranous proteoglycans that serves as a coreceptor for a wide pool of extracellular ligands, has been well documented in enabling the promotion of growth and invasion of endometrial cancer. As a step toward understanding a potential role for syndecan-1 in this process, we questioned whether syndecan-1 upregulates tumor-promoting characteristics, particularly, angiogenesis in an in vivo human xenograft tumor model.

METHODS

Human syndecan-1 was stably transfected into human endometrial adenocarcinoma 1A cells, and resulting transfectants were subcutaneously grafted into athymic mice; their outcomes were examined with respect to the enhancement of tumor growth and angiogenesis by immunohistochemistry, immunoblotting, and zymography.

RESULTS

Overexpression of syndecan-1 promoted tumor growth concomitant with increased angiogenesis in tumor xenografts as evidenced by an increase in immunoreactivity for vascular endothelial growth factor and vascular endothelial cell marker CD34. Furthermore, zymographic studies revealed that syndecan-1 overexpression markedly enhanced activities of matrix metalloproteinases 2 and 9.

CONCLUSIONS

This is the first in vivo xenograft analysis providing evidence that supports that syndecan-1 has a critical role in carcinogenic progression, particularly, contributing to the development of angiogenesis and invasive phenotype in association with matrix metalloproteinases 2 and 9 activations in endometrial cancer.

Immunohistochemical study identifying prognostic biomolecular markers in nasopharyngeal carcinoma treated by radiotherapy

BACKGROUND

We evaluated the predictive significance of 14 reported markers using immunohistochemical study in nasopharyngeal carcinoma.

METHODS

Immunohistochemical stainings were done in 38 patients for Met, cyclooxygenase-2 (COX-2), nm23-H1, epidermal growth factor receptor (EGFR), p63, early growth response factor 1 (Egr1), chromosome segregation 1-like (CSE1L), cathepsin-D (aspartyl protease), C-erbB2, p53, signal transducers and activators of transcription (STAT3/STAT5), CD138 (Syndecan-1), and LIN28 with the usual methods.

RESULTS

The median follow-up time was 30 months (11-83 months). High Met and CD138 expression were statistically significant negative prognostic factors on survival. The expression of Egr1 had a positive prognostic effect on survival. The combined score of these 3 markers, Met plus CD138 minus Egr1, was a strong prognostic factor. The median survival curve was distinctly separated in accord with this combined score. No prognostic value was revealed in COX-2, nm23-H1, EGFR, p63, CSE1L, cathepsin-D, C-erbB2, p53, STAT3, STAT5, and LIN28.

CONCLUSIONS

The combined score of these markers could be used to stratify biomolecular risk groups.

Distinguishing medullary carcinoma of the breast from high-grade hormone receptor-negative invasive ductal carcinoma: an immunohistochemical approach

AIMS

Medullary carcinomas (MCs) represent a rare breast cancer subtype associated with a rather favourable prognosis compared with invasive ductal carcinomas (IDCs). Due to histopathological overlap, MCs are frequently misclassified as high-grade IDCs, potentially leading to overtreatment of MCs. Our aim was to establish novel diagnostic markers distinguishing MCs from hormone receptor-negative high-grade IDCs.

METHODS AND RESULTS

Sixty-one MCs and 133 hormone receptor-negative IDCs were analysed in a comparative immunohistochemical study. Applied markers included a comprehensive panel of cytokeratins (CKs), vimentin, smooth muscle actin (SMA), p63, p53, cell adhesion molecules [N-CAM (CD56), syndecan-1 (CD138), E-cadherin and P-cadherin] and development associated transcription factors (AP-2 alpha, AP-2 gamma). A significantly higher proportion of IDCs displayed increased expression of CK7, AP-2 alpha and HER2 in contrast to MCs (CK7: 91% of IDCs versus 77% of MCs; AP-2 alpha: 77% versus 57%; and HER2: 26% versus 7%, each P < 0.01). Vice versa, MCs were slightly more frequently positive for SMA and vimentin (P > 0.05).

CONCLUSIONS

Hormone receptor-negative high-grade IDCs are significantly associated with luminal differentiation, Her2 and AP-2 alpha overexpression, whereas MCs tend to display myoepithelial features. Markers analysed in this study are of diagnostic value regarding the differential diagnosis of MCs.

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.

Expression of syndecan-1 and cathepsins D and K in advanced esophageal squamous cell carcinoma

The key features of malignant neoplasms are their local invasiveness and metastatic potential. Syndecan-1 - integral membrane heparan sulfate proteoglycan and cathepsins D and K - lysosomal proteases are important factors influencing different aspects of these processes. The study was undertaken to determine their expression in esophageal squamous cell carcinoma, and analyze relationship to selected clinicopathological features as well as to survival. Formalin-fixed, paraffin-embedded sections from 39 advanced esophageal squamous cell carcinoma were used for immunohistochemical staining. The epithelial and stromal staining were evaluated separately and compared to conventional clinicopathological features and one-year survival. Positive epithelial immunostaining for syndecan-1, cathepsin D and K were observed in 82.05%, 56.41% and 30.77% of tumors, respectively. However, stromal staining was noted in 51.28%, 51.28% and 46.15% ones, respectively. Epithelial syndecan-1-positive cases were significantly more frequent in well- and moderately differentiated carcinomas. Stromal cathepsin D expression predominated in tumors with infiltrative growth pattern. However, there were no statistically significant differences between any marker-positive and -negative groups with respect to other clinicopathological features studied. The only factors significantly influencing one-year survival were epithelial cathepsin D staining and distant metastasis. In a group of patients who survived one year post surgery, the percentage of cases with negative epithelial cathepsin D staining and without features of distant metastasis were higher. The results may suggest a relationship between syndecan-1 and cathepsins D and K with growth and invasiveness of esophageal squamous cell carcinoma, but such thesis requires further study on a larger and more heterogeneous population.

Transmembrane signaling proteoglycans

Virtually all metazoan cells contain at least one and usually several types of transmembrane proteoglycans. These are varied in protein structure and type of polysaccharide, but the total number of vertebrate genes encoding transmembrane proteoglycan core proteins is less than 10. Some core proteins, including those of the syndecans, always possess covalently coupled glycosaminoglycans; others do not. Syndecan has a long evolutionary history, as it is present in invertebrates, but many other transmembrane proteoglycans are vertebrate inventions. The variety of proteins and their glycosaminoglycan chains is matched by diverse functions. However, all assume roles as coreceptors, often working alongside high-affinity growth factor receptors or adhesion receptors such as integrins. Other common themes are an ability to signal through their cytoplasmic domains, often to the actin cytoskeleton, and linkage to PDZ protein networks. Many transmembrane proteoglycans associate on the cell surface with metzincin proteases and can be shed by them. Work with model systems in vivo and in vitro reveals roles in growth, adhesion, migration, and metabolism. Furthermore, a wide range of phenotypes for the core proteins has been obtained in mouse knockout experiments. Here some of the latest developments in the field are examined in hopes of stimulating further interest in this fascinating group of molecules.

The expression of syndecan-1, syndecan-4 and decorin in healthy human breast tissue during the menstrual cycle

BACKGROUND

In order to unravel the interactions between the epithelium and the extra cellular matrix (ECM) in breast tissue progressing to cancer, it is necessary to understand the relevant interactions in healthy tissue under normal physiologic settings. Proteoglycans in the ECM play an important role in the signaling between the different tissue compartments. The proteoglycan decorin is abundant in the breast stroma. Decreased expression in breast cancer tissue is a sign of a poor tumor prognosis. The heparane sulphate proteoglycans syndecan-1 and syndecan-4 promote the integration of cellular adhesion and proliferation. The aim of this study was to investigate the gene expression and location of decorin, syndecan-1 and syndecan-4 in the healthy breast during the menstrual cycle.

METHODS

Tissue from healthy women undergoing breast reduction plastic surgery was examined using immunohistochemistry (n = 38) and Real-Time RT-PCR (n = 20). Both parous and nulliparous women were eligible and the mean age of the women was 34(+/- 10 years) with regular menstrual cycles (28 +/- 7 days). None of the women had used hormonal treatment the last three months. The women were randomized to needle biopsy two months before the operation in the follicular or luteal menstrual phase and for another biopsy at the operation in the opposite phase. Serum samples were obtained to characterize the menstrual phase. The Wilcoxon signed rank test and Mann Whitney test were used for statistical analyses.

RESULTS

By real time-RT-PCR the gene signal for all three proteoglycans; decorin (p = 0.02) and syndecan-1 (p = 0.03) and syndecan-4 (p = 0.02) was significantly lower among parous women in the luteal phase than in the follicular phase. Immunohistochemistry confirmed the identification of the proteins but no significant difference between menstrual phases was observed. Serum samples verified the menstrual phase.

CONCLUSIONS

Our study shows, for the first time in the healthy breast, a significantly lower expression of the genes for the three proteoglycans, decorin, syndecan-1 and syndecan-4 in the luteal phase during the menstrual cycle. These changes were registered under normal physiologic conditions. Since ECM molecules appear to be involved in tumor progression, these findings in the normal breast could constitute a base for further studies in women receiving hormonal therapy or those with breast cancer.

The expression of syndecan-1 is related to the risk of endometrial hyperplasia progressing to endometrial carcinoma

OBJECTIVE

Aberrant expression of the cell surface proteoglycan, syndecan-1, is found in many malignancies. The current study describes the immunohistochemical study of syndecan-1 expression in normal, hyperplastic, and malignant endometrial tissues for evaluation of application as a parameter of cancer progression in patients with endometrial hyperplasia.

METHODS

Immunohistochemical staining of syndecan-1 was performed in 101 formalin fixed, paraffin embedded sections of normal, hyperplastic, and malignant endometrial tissues. We analyzed specimens from patients with normal endometrium (NE, N=10) as controls, and those of simple hyperplasia (SH, N=20), complex hyperplasia without atypia (CH, N=20), atypical hyperplasia (AH, N=20), and endometrial cancer (EC, N=31).

RESULTS

The mean rank of expression scores based on the frequency of syndecan-1 staining were 31.6, 20.5, 52.9, 72.1, and 62.1 for NE, SH, CH, AH and EC, respectively (p<0.001). Syndecan-1 expression was significantly greater in CH (p<0.001) or AH (p<0.001) than in SH, and significantly greater in AH compared to CH (p=0.028). Syndecan-1 is more frequently expressed in CH (p=0.042), AH (p<0.001), or EC (p=0.002) than in NE. Syndecan-1 expression did not differ significantly between NE and SH (p=0.248).

CONCLUSION

Syndecan-1 expression appears to be useful as a predictive indicator in endometrial hyperplasia.

Expression of syndecan-1 in papillary carcinoma of the thyroid with extracapsular invasion

BACKGROUND AND AIMS

Syndecan-1 (SDC-1) is a member of the family of transmembrane heparan sulfate proteoglycans, which are involved in cell-cell adhesion and the interaction of cells with the extracellular matrix. Evidence suggests that loss of SDC-1 expression in several benign and malignant epithelial neoplasms is an unfavorable prognostic indicator, but its expression profile in thyroid gland neoplasms remains to be elucidated. The aim of this study was to evaluate SDC-1 expression in papillary carcinomas of the thyroid (PCT) that were both larger and smaller (papillary microcarcinoma) than 10mm, with or without extracapsular extension (PCT-E and PCT-NE).

METHODS

The expression of SDC-1 was studied in 62 cases of PCT-E and PCT-NE using a tissue microarrays technique (TMA). SDC-1 positivity was predominantly observed in the cytoplasm of neoplastic epithelial cells and in the stroma of PCT.

RESULTS

SDC-1 is expressed in both neoplastic epithelial cells and the stroma. It is more frequently expressed in PCT-E than PCT-NE (p=0.002) and the stromal expression of SDC-1 is more intense in PCT-E that are >10 mm (p=0.026).

CONCLUSIONS

The epithelial and stromal expression of SDC-1 observed in this series of PCT suggests that the expression of this protein may be related to extracapsular invasion.

Sdc1 negatively modulates carcinoma cell motility and invasion

During cancer progression, tumor cells eventually invade the surrounding collagen-rich extracellular matrix. Here we show that squamous cell carcinoma cells strongly adhere to Type I collagen substrates but display limited motility and invasion on collagen barriers. Further analysis revealed that in addition to the alpha2beta1 integrin, a second collagen receptor was identified as Syndecan-1 (Sdc1), a cell surface heparan sulfate proteoglycan. We demonstrate that siRNA-mediated depletion of Sdc1 reduced adhesion efficiency to collagen I, whereas knockdown of Sdc4 was without effect. Importantly, silencing Sdc1 expression caused reduced focal adhesion plaque formation and enhanced cell spreading and motility on collagen I substrates, but did not alter cell motility on other ECM substrates. Sdc1 depletion ablated adhesion-induced RhoA activation. In contrast, Rac1 was strongly activated following Sdc1 knockdown, suggesting that Sdc1 may mediate the link between integrin-induced actin remodeling and motility. Taken together, these data substantiate the existence of a co-adhesion receptor system in tumor cells, whereby Sdc1 functions as a key regulator of cell motility and cell invasion by modulating RhoA and Rac activity. Downregulation of Sdc1 expression during carcinoma progression may represent a mechanism by which tumor cells become more invasive and metastatic.

Proteoglycans: master modulators of paracrine fibroblast-carcinoma cell interactions

Reciprocal interactions between tumor and stromal cells govern carcinoma growth and progression. Signaling functions between these cell types in the tumor microenvironment are largely carried out by secreted growth factors and cytokines. This review discusses how proteoglycans, which are abundantly present in normal and neoplastic tissues, modulate paracrine growth factor signaling events. General principles of proteoglycan involvement in paracrine signaling include stromal induction, core protein processing by proteases and growth factor binding via proteoglycan glycosaminoglycan chains or core protein domains.

Proteoglycan signaling co-receptors: roles in cell adhesion, migration and invasion

Signaling co-receptors are diverse, multifunctional components of most major signaling pathways, with roles in mediating and regulating signaling in both physiological and pathophysiological circumstances. Many of these signaling co-receptors, including CD44, glypicans, neuropilins, syndecans and TssRIII/betaglycan are also proteoglycans. Like other co-receptors, these proteoglycan signaling co-receptors can bind multiple ligands, promoting the formation of receptor signaling complexes and regulating signaling at the cell surface. The proteoglycan signaling co-receptors can also function as structural molecules to regulate adhesion, cell migration, morphogenesis and differentiation. Through a balance of these signaling and structural roles, proteoglycan signaling co-receptors can have either tumor promoting or tumor suppressing functions. Defining the role and mechanism of action of these proteoglycan signaling co-receptors should enable more effective targeting of these co-receptors and their respective pathways for the treatment of human disease.

Expression of syndecan-1 in histologically normal breast tissue from postmenopausal women with breast cancer according to mammographic density

OBJECTIVE

To analyze the expression of Syndecan-1 in dense and non-dense human breast tissue.

METHODS

Specimens of histologically normal tissue were obtained from postmenopausal women undergoing surgery for breast cancer. Each tissue block was subject to radiological examination and pair-wise samples of dense and non-dense tissue were collected. Semi-quantitative assessment of immunohistochemical staining intensity for Syndecan-1 and estrogen receptor subtypes was performed.

RESULTS

The expression of Syndecan-1 in all tissue compartments was significantly higher in dense than in non-dense specimens. The strongest staining was recorded in stromal tissue. There was a strong correlation between epithelial estrogen receptor alpha and stromal cell Syndecan-1 expression in dense tissue (rs = 0.7; p = 0.02). This association was absent in non-dense tissue.

CONCLUSION

An increase of Syndecan-1 in all tissue compartments and a redistribution from epithelium to stroma may be a characteristic feature for dense breast tissue.

Differential roles for membrane-bound and soluble syndecan-1 (CD138) in breast cancer progression

The heparan sulfate proteoglycan syndecan-1 (Sdc1) modulates cell proliferation, adhesion, migration and angiogenesis. Proteinase-mediated shedding converts Sdc1 from a membrane-bound coreceptor into a soluble effector capable of binding the same ligands. In breast carcinomas, Sdc1 overexpression correlates with poor prognosis and an aggressive phenotype. To distinguish between the roles of membrane-bound and shed forms of Sdc1 in breast cancer progression, human MCF-7 breast cancer cells were stably transfected with plasmids overexpressing wild-type (WT), constitutively shed and uncleavable forms of Sdc1. Overexpression of WT Sdc1 increased cell proliferation, whereas overexpression of constitutively shed Sdc1 decreased proliferation. Fibroblast growth factor-2-mediated mitogen-activated protein kinase signaling was reduced following small-interfering RNA (siRNA)-mediated knockdown of Sdc1 expression. Constitutively, membrane-bound Sdc1 inhibited invasiveness, whereas soluble Sdc1 promoted invasion of MCF-7 cells into matrigel matrices. The latter effect was reversed by the matrix metalloproteinase inhibitors N-isobutyl-N-(4-methoxyphenylsufonyl) glycyl hydroxamic acid and tissue inhibitor of metalloproteinase (TIMP)-1. Affymetrix microarray analysis identified TIMP-1, Furin and urokinase-type plasminogen activator receptor as genes differentially regulated in soluble Sdc1-overexpressing cells. Endogenous TIMP-1 expression was reduced in cells overexpressing soluble Sdc1 and increased in those overexpressing the constitutively membrane-bound Sdc1. Moreover, E-cadherin protein expression was downregulated in cells overexpressing soluble Sdc1. Our results suggest that the soluble and membrane-bound forms of Sdc1 play different roles at different stages of breast cancer progression. Proteolytic conversion of Sdc1 from a membrane-bound into a soluble molecule marks a switch from a proliferative to an invasive phenotype, with implications for breast cancer diagnostics and potential glycosaminoglycan-based therapies.

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.

Peroxisome proliferator-activated receptor gamma-mediated up-regulation of syndecan-1 by n-3 fatty acids promotes apoptosis of human breast cancer cells

Diets enriched in n-3 polyunsaturated fatty acids (n-3 PUFA) may protect against breast cancer but biochemical mechanisms are unclear. Our studies showed that the n-3 fatty acid docosahexaenoic acid (DHA) up-regulated syndecan-1 (SDC-1) in human breast cancer cells, and we tested the hypothesis that DHA-mediated up-regulation of SDC-1 induces apoptosis. DHA was delivered to MCF-7 cells by n-3 PUFA-enriched low-density lipoproteins (LDL) or by albumin in the presence or absence of SDC-1 small interfering RNA. The n-3 PUFA induced apoptosis, which was blocked by SDC-1 silencing. We also confirmed that SDC-1 up-regulation and apoptosis promotion by n-3 PUFA was mediated by peroxisome proliferator-activated receptor gamma (PPAR gamma). Using a luciferase gene driven by either a PPAR response element or a DR-1 site present in the SDC-1 promoter, reporter activities were enhanced by n-3 LDL, DHA, and PPAR gamma agonist, whereas activity of a luciferase gene placed downstream of a mutant DR-1 site was unresponsive. Cotransfection with dominant-negative PPAR gamma DNA eliminated the increase in luciferase activity. These data provide strong evidence that SDC-1 is a molecular target of n-3 PUFA in human breast cancer cells through activation of PPAR gamma and that n-3 PUFA-induced apoptosis is mediated by SDC-1. This provides a novel mechanism for the chemopreventive effects of n-3 PUFA in breast cancer.

Proteoglycans: key partners in bone cell biology

The diversity of bone proteoglycan (PG) structure and localisation (pericellular, extracellular in the organic bone matrix) reflects a broad spectrum of biological functions within a unique tissue. PGs play important roles in organizing the bone extracellular matrix, taking part in the structuring of the tissue itself as active regulators of collagen fibrillogenesis. PGs also display selective patterns of reactivity with several constituents including cytokines and growth factors, such as transforming growth factor-beta or osteoprotegerin thereby modulating their bio-availability and biological activity in the bone tissue. In this review, the complex PG composition in bone will be addressed together with the specific role played by PGs (or their GAGs chains) in bone biology, as regulatory molecules for bone resorption and their involvement in bone tumor development. These roles have been determined after modulation of PG expression or mutations in their corresponding genes, which revealed specific roles for these compounds in bone pathologies (e.g. perlecan or glypican-3 mutations observed respectively in chondrodysplasia or dysmorphic syndrome). Finally, the potential therapeutic interest of PGs is discussed based on recent data, more particularly on bone tumor-associated osteolysis as these molecules are involved both in bone resorption and tumor development.

Syndecan-1, a key regulator of cell viability in endometrial cancer

Syndecan-1 is one of the major proteoglycans on cell surfaces involved in major biological processes. Although loss of syndecan-1 correlates well with the gain of cancerous characteristics in a wide range of cancers, increased expression of syndecan-1 also coincides with adverse outcomes in some cancers, including breast, ovarian and pancreatic cancers. For this Janus-faced attitude of syndecan-1, we sought to examine expression patterns of syndecan-1 in endometrial carcinoma (EC) and gain insight into the roles of syndecan-1. Immunohistochemical examinations of 109 endometrial tissue samples from myoma, hyperplasia and EC uteri revealed that syndecan-1 expression was significantly upregulated in EC compared with hyperplasia (p < 0.001). To evaluate pathophysiological functions of syndecan-1, its expression level was altered, and subsequent outcomes were examined using human endometrial cancer cell lines such as HEC-1A, AN3CA and KLE cells. Overexpression of syndecan-1 increased the growth of HEC-1A cells regardless of anchorage dependence while silencing syndecan-1 by antisense RNAs caused apoptotic cell death. Consistent with decreased viability, the loss of syndecan-1 was also accompanied by a decrease in the activation of Erk and Akt and a concomitant decrease in the phosphorylation of PTEN and PDK1, which are known as negative and positive regulators of Akt activation, respectively. These down-regulatory effects were reversed upon overexpression of syndecan-1. Collectively together, the aforementioned findings lend support to the notion that upregulation of syndecan-1 may be a critical element for endometrial cancers in maintaining their viability and thus can serve as a cancer specific therapeutic and diagnostic marker.

Aberrant fibroblast growth factor receptor signaling in bladder and other cancers

Fibroblast growth factors (FGFs) are potent mitogens, morphogens, and inducers of angiogenesis, and FGF signaling governs the genesis of diverse tissues and organs from the earliest stages. With such fundamental embryonic and homeostatic roles, it follows that aberrant FGF signaling underlies a variety of diseases. Pathological modifications to FGF expression are known to cause salivary gland aplasia and autosomal dominant hypophosphatemic rickets, while mutations in FGF receptors (FGFRs) result in a range of skeletal dysplasias. Anomalous FGF signaling is also associated with cancer development and progression. Examples include the overexpression of FGF2 and FGF6 in prostate cancer, and FGF8 overexpression in breast and prostate cancers. Alterations in FGF signaling regulators also impact tumorigenesis, which is exemplified by the down-regulation of Sprouty 1, a negative regulator of FGF signaling, in prostate cancer. In addition, several FGFRs are mutated in human cancers (including FGFR2 in gastric cancer and FGFR3 in bladder cancer). We recently identified intriguing alterations in the FGF pathway in a novel model of bladder carcinoma that consists of a parental cell line (TSU-Pr1/T24) and two sublines with increasing metastatic potential (TSU-Pr1-B1 and TSU-Pr1-B2), which were derived successively through in vivo cycling. It was found that the increasingly metastatic sublines (TSU-Pr1-B1 and TSU-Pr1-B2) had undergone a mesenchymal to epithelial transition. FGFR2IIIc expression, which is normally expressed in mesenchymal cells, was increased in the epithelial-like TSU-Pr1-B1 and TSU-Pr1-B2 sublines and FGFR2 knock-down was associated with the reversion of cells from an epithelial to a mesenchymal phenotype. These observations suggest that modified FGF pathway signaling should be considered when studying other cancer types.

Establishment and characterization of a high metastatic potential in the peritoneum for human gastric cancer by orthotopic tumor cell implantation

The aim of this study was to establish an orthotopic implantation model with high metastasis of gastric cancer to the peritoneum which is more faithful to clinical metastasis. A human gastric carcinoma cell line, GC9811, was injected as a single-cell suspension into the stomach of nude mice. The cells from some peritoneum metastatic foci were expanded in vitro and subsequently implanted to the stomach wall of nude mice. By repeating the in vivo stepwise selection method for four rounds and cloning culture, we obtained a cell line designated GC9811-P, which developed peritoneal metastasis in 13 of 13 (100%) of mice, compared with only 20% of those implanted with parental GC9811. The metastatic foci in the peritoneum showed essentially the same histological appearance as those induced by parental cells. Tumor cell growth of GC9811-P in vitro was faster than that of GC9811. Motility assays demonstrated higher motility of GC9811-P than of GC9811. The adhesive ability of GC9811-P cells to laminin was lower than that of GC9811 cells, whereas the ability of GC9811-P cells to adhere to fibronectin was significantly higher than that of parental cells. Differences between GC9811-P and their parental GC9811 cells were found in expression levels of various molecules by flow cytometric and western blot. The findings indicated that up-regulation in the expressions of CD155, VEGF, syndecan-1, and syndecan-2 or down-regulation in the expressions of IL-6 and E-cadherin play an important role in the peritoneal metastasis of human gastric carcinoma cells. The high-metastatic cell line appears to be useful for investigating the mechanisms of peritoneal metastasis and preventing peritoneal metastasis of human gastric cancer.

An expression signature of syndecan-1 (CD138), E-cadherin and c-met is associated with factors of angiogenesis and lymphangiogenesis in ductal breast carcinoma in situ

INTRODUCTION

Heparan sulphate proteoglycan syndecan-1 modulates cell proliferation, adhesion, migration and angiogenesis. It is a coreceptor for the hepatocyte growth factor receptor c-met, and its coexpression with E-cadherin is synchronously regulated during epithelial-mesenchymal transition. In breast cancer, changes in the expression of syndecan-1, E-cadherin and c-met correlate with poor prognosis. In this study we evaluated whether coexpression of these functionally linked prognostic markers constitutes an expression signature in ductal carcinoma in situ (DCIS) of the breast that may promote cell proliferation and (lymph)angiogenesis.

METHODS

Expression of syndecan-1, E-cadherin and c-met was detected immunohistochemically using a tissue microarray in tumour specimens from 200 DCIS patients. Results were correlated with the expression patterns of angiogenic and lymphangiogenic markers. Coexpression of the three prognostic markers was evaluated in human breast cancer cells by confocal immunofluorescence microscopy and RT-PCR.

RESULTS

Coexpression and membrane colocalization of the three markers was confirmed in MCF-7 cells. E-cadherin expression decreased, and c-met expression increased progressively in more aggressive cell lines. Tissue microarray analysis revealed strong positive staining of tumour cells for syndecan-1 in 72%, E-cadherin in 67.8% and c-met in 48.6% of DCIS. E-cadherin expression was significantly associated with c-met and syndecan-1. Expression of c-met and syndecan-1 was significantly more frequent in the subgroup of patients with pure DCIS than in those with DCIS and a coexisting invasive carcinoma. Levels of c-met and syndecan-1 expression were associated with HER2 expression. Expression of c-met significantly correlated with expression of endothelin A and B receptors, vascular endothelial growth factor (VEGF)-A and fibroblast growth factor receptor-1, whereas E-cadherin expression correlated significantly with endothelin A receptor, VEGF-A and VEGF-C staining.

CONCLUSION

Syndecan-1, E-cadherin and c-met constitute a marker signature associated with angiogenic and lymphangiogenic factors in DCIS. This coexpression may reflect a state of parallel activation of different signal transduction pathways, promoting tumour cell proliferation and angiogenesis. Our findings have implications for future therapeutic approaches in terms of a multiple target approach, which may be useful early in breast cancer progression.

Shedding of Syndecan-1 by Stromal Fibroblasts Stimulates Human Breast Cancer Cell Proliferation via FGF2 Activation

The cell surface heparan sulfate proteoglycan syndecan-1 is induced in stromal fibroblasts of breast carcinomas and participates in a reciprocal feedback loop, which stimulates carcinoma cell growth in vitro and in vivo. To define the molecular mechanism of carcinoma growth stimulation, a three-dimensional co-culture model was developed that combines T47D breast carcinoma cells with immortalized human mammary fibroblasts in collagen gels. By silencing endogenous syndecan-1 induction with short interfering RNA and expressing mutant murine syndecan-1 constructs, it was determined that carcinoma cell mitogenesis required proteolytic shedding of syndecan-1 from the fibroblast surface. The paracrine growth signal was mediated by the syndecan-1 heparan lfate chains rather than the ectodomain of the core protein and required fibroblast growth factor 2 and stroma-derived factor 1. This paracrine pathway may provide an opportunity for the therapeutic disruption of stromaepithelial signaling.

Syndecan-2 Affects the Basal and Chemotherapy-Induced Apoptosis in Osteosarcoma

Syndecans are transmembrane heparan sulfate proteoglycans controlling cell adhesion, migration, and proliferation. We previously showed that syndecan-2 is involved in the control of apoptosis in cultured osteosarcoma cells. These data led us to the hypothesis that syndecan-2 may play a role in the apoptotic signaling in bone tumors. We immunohistochemically analyzed tissue sections from biopsies from 21 patients with well-characterized osteosarcoma. These tissues expressed low levels of syndecan-2 compared with osteoblasts and osteocytes in normal bone. Cultured human osteosarcoma cells also produced lower mRNA levels of syndecan-2 than normal osteoblastic cells. Moreover, the presence of syndecan-2 correlated with spontaneous apoptosis in osteosarcoma tissues as assessed by detection of DNA fragmentation in situ. Overexpression of syndecan-2 resulted in decreased number of migrating and invading U2OS osteosarcoma cells in Matrigel. In addition, overexpression of syndecan-2 sensitized human osteosarcoma cells to chemotherapy-induced apoptosis, increasing the response to methotrexate, doxorubicin, and cisplatin. Consistently, knockdown of the proteoglycan using stable transfection with a plasmid coding small interfering RNA resulted in inhibition of chemotherapy-induced apoptosis. Analysis of syndecan-2 expression both in biopsies and in corresponding postchemotherapy-resected tumors, as well as in cells treated with methotrexate or doxorubicin, showed that the cytotoxic action of chemotherapy can be associated with an increase in syndecan-2. These results provide support for a tumor-suppressor function for syndecan-2 and suggest that dysregulation of apoptosis may be related to abnormal syndecan-2 expression or induction in osteosarcoma. Moreover, our data identify syndecan-2 as a new factor mediating the antioncogenic effect of chemotherapeutic drugs.

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.