Reduction of syndecan-1 mRNA in cervical-carcinoma cells is involved with the 3' untranslated region

Aberrant Expression of Syndecan-1 in Cervical Cancers

Syndecan-1, is a transmembrane heparan/chondroitin sulfate proteoglycan necessary for cell-cell and cell-matrix interactions. Its decreased level on the cell surface correlates with poor prognosis in several tumor types. Aberrant stromal localization of syndecan-1 is also considered an unfavorable prognostic factor in various human malignancies. In the presented work the question was addressed if changes in syndecan-1 expression are related to the prognosis of cervical cancer. Immunohistochemistry for syndecan-1 extracellular domain was performed on surgical specimens of primary cervical cancer. To follow the communication between tumor cells and stromal fibroblasts, their mono-and co-cultures were studied, detecting the expression of syndecan-1, smooth muscle actin, vimentin, and desmin. Immunohistochemistry of tumorous specimens revealed that while cell surface syndecan-1 expression was reduced on cancer cells, it appeared on the surface of tumor-associated fibroblasts. Until year 7, the cohort with high cell surface syndecan-1 expression had significantly longer survival. No difference in the same time-period could be detected when stromal syndecan-1 expression was analyzed. In vitro analysis revealed, that tumor cells can induce syndecan-1 expression on fibroblast, and fibroblasts showed that fibroblast-like cells are built by two cell types: (a) syndecan-1 positive, cytokeratin negative real fibroblasts, and (b) syndecan-1 and cytokeratin positive epithelial-mesenchymal transformed tumor cells. Syndecan-1 on the surface of cancer cells appears to be a positive prognostic marker. Although syndecan-1 positive fibroblasts promote tumor cell proliferation in vitro, we failed to detect their cancer promoting effect in vivo.

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.

Syndecans as modulators and potential pharmacological targets in cancer progression

Extracellular matrix (ECM) components form a dynamic network of key importance for cell function and properties. Key macromolecules in this interplay are syndecans (SDCs), a family of transmembrane heparan sulfate proteoglycans (HSPGs). Specifically, heparan sulfate (HS) chains with their different sulfation pattern have the ability to interact with growth factors and their receptors in tumor microenvironment, promoting the activation of different signaling cascades that regulate tumor cell behavior. The affinity of HS chains with ligands is altered during malignant conditions because of the modification of chain sequence/sulfation pattern. Furthermore, matrix degradation enzymes derived from the tumor itself or the tumor microenvironment, like heparanase and matrix metalloproteinases, ADAM as well as ADAMTS are involved in the cleavage of SDCs ectodomain at the HS and protein core level, respectively. Such released soluble SDCs "shed SDCs" in the ECM interact in an autocrine or paracrine manner with the tumor or/and stromal cells. Shed SDCs, upon binding to several matrix effectors, such as growth factors, chemokines, and cytokines, have the ability to act as competitive inhibitors for membrane proteoglycans, and modulate the inflammatory microenvironment of cancer cells. It is notable that SDCs and their soluble counterparts may affect either the behavior of cancer cells and/or their microenvironment during cancer progression. The importance of these molecules has been highlighted since HSPGs have been proposed as prognostic markers of solid tumors and hematopoietic malignancies. Going a step further down the line, the multi-actions of SDCs in many levels make them appealing as potential pharmacological targets, either by targeting directly the tumor or indirectly the adjacent stroma.

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

OBJECTIVES

Loss of epithelial heparan sulfate proteoglycan syndecan-1 has been associated with a more aggressive behavior in various cancer forms, but the prognostic significance of syndecan-1 expression in colorectal cancer is unclear. The aim of this study was to evaluate the prognostic value of immunohistochemical syndecan-1 expression in a series of 237 patients with colorectal cancer.

METHODS

Paraffin-embedded formalin-fixed specimens were stained with a syndecan-1-specific monoclonal antibody, and both the epithelial and stromal expression were analyzed.

RESULTS

Epithelial expression of syndecan-1 was seen in 222 tumors (94%), and it was associated with low stage of disease (p = 0.002) and low histological differentiation grade (p = 0.048). The cumulative 5-year survival of patients with weak and strong syndecan-1 expression was 49 and 54 %, respectively (p = 0.234). Syndecan-1 stromal immunoreactivity was observed in 138 tumors (58%), but lacked prognostic significance. Staining pattern and distribution can be viewed from digitized representative microscope slides (virtual slides) at http://www.webmicroscope.net/supplements/syndecan.

CONCLUSIONS

The results are in line with previous reports in that low epithelial syndecan-1 expression was associated with a higher histological grade and a more advanced clinical stage of the patients. This study shows that syndecan-1 is expressed also in stromal tissue of colorectal cancer, but it does not support the proposed role of stromal syndecan-1 expression as a marker of poor clinical outcome.

Cellular process classification of human papillomavirus-16-positive SiHa cervical carcinoma cell using Gene Ontology

This study utilized mRNA differential display and the Gene Ontology (GO) analysis to characterize the multiple interactions of a number of genes involved in human papillomavirus (HPV)-16-induced cervical carcinogenesis. We used HPV-16-positive cervical cancer cell line (SiHa) and normal human keratinocyte cell line (HaCaT) as a control. Each gene has several biological functions in the GO, and hence, we chosen the several functions for each gene. and then, the specific functions were correlated with gene expression patterns. The results showed that 157 genes were up- or down-regulated above two-fold and organized into mutually dependent subfunction sets depending on the cervical cancer pathway, suggesting the potentially significant genes of unknown function. The GO analysis suggested that cervical cancer cells underwent repression of cancer-specific cell-adhesive properties. Also, genes belonging to DNA metabolism such as DNA repair and replication were strongly down-regulated, whereas significant increases were shown in protein degradation and in protein synthesis. The GO analysis can overcome the complexity of the gene expression profile of the HPV-16-associated pathway and identify several cancer-specific cellular processes as well as genes of unknown function. Also, it can become a major competing platform for the genome-wide characterization of carcinogenesis.

Changes of cell adhesion and extracellular matrix (ECM) components in cervical intraepithelial neoplasia

Cell-cell and cell-extracellular matrix interaction is crucial in tumor progression. Tight junction (TJ) proteins as occludin and claudins (CLDNs) play important role in this process together with several extracellular matrix components, as syndecan. Our previous work suggested significant changes in the expression of claudins even in the early stages of cervical carcinogenesis. The aim of our present work was to study the expression of occludin and syndecan-1, as compared to CLDNs, in early phases of cervical carcinogenesis. Paraffin sections of 50 samples were studied by immunohistochemistry, including cervical intraepithelial neoplasias (CINI-II-III), in situ carcinomas (CIS) and normal cervical samples. Occludin and CLDN-2 were found colocalized in the basal layer, while syndecan-1 and CLDN-1, -4 and -7 were coexpressed in the parabasal and intermedier layers in normal epithelia. Intensity of occludin staining decreased in CIN/CIS lesions, although it was more extended towards the upper epithelial layers with inverse relation with grades, as seen in the case of CLDN-2 expression. CLDN-1, -2, -4 and -7 were detected in the entire epithelium in CIN, showing decrease in CIS. The progression of CIN was associated with reduced syndecan-1 expression, in contrast to CLDN-1, -4 and -7 which increased toward CIS. The obtained data suggest that significant changes occur in the composition of cell adhesion complexes even in early stages of cervical carcinogenesis. The pattern of expression is characteristic for the alteration, the changes in the different components, however, are not parallel with each other.

Searching for pathogenic gene functions to cervical cancer

OBJECTIVES

Molecular pathology of cervical cancers associated with human papillomavirus (HPV) infection is presently unclear. In an effort to clarify this issue, we investigated gene expression profiles and pathogenic cellular processes of cervical cancer lesions.

METHODS

Tissues of 11 patients (invasive cancer stages Ib-IIIa) were investigated by a cDNA microarray of 4700 genes, hierarchical clustering and the Gene Ontology (GO).

RESULTS

We identified 74 genes showing a more than 2-fold difference in their expression in at least 8 out of 11 patients. Among these, 33 genes were up-regulated, in contrast, 41 genes were down-regulated. The gene expression profiles were classified into mutually dependent 345 function sets, resulting in 611 cellular processes according to the GO. The GO analysis showed that cervical carcinogenesis underwent complete down-regulation of cell death, protein biosynthesis, and nucleic acid metabolism. Also, genes belonging to nucleic acid binding and structural molecule activity were significantly down-regulated. In contrast, significant up-regulation was shown in skeletal development, immune response, and extracellular activity.

CONCLUSIONS

These data suggest that the regulated genes and cellular processes could be further used for predicting prognosis and diagnosis of cervical cancer patients, and further investigation and functional characterization of the identified genes is warranted.

Syndecans in tumor cell adhesion and signaling

Anchorage of cells to "heparin"--binding domains that are prevalent in extracellular matrix (ECM) components is thought to occur primarily through the syndecans, a four-member family of transmembrane heparan sulfate proteoglycans that communicate environmental cues from the ECM to the cytoskeleton and the signaling apparatus of the cell. Known activities of the syndecans trace to their highly conserved cytoplasmic domains and to their heparan sulfate chains, which can serve to regulate the signaling of growth factors and morphogens. However, several emerging studies point to critical roles for the syndecans' extracellular protein domains in tumor cell behavior to include cell adhesion and invasion. Although the mechanisms of these activities remain largely unknown, one possibility involves "co-receptor" interactions with integrins that may regulate integrin function and the cell adhesion-signaling phenotype. Thus, alterations in syndecan expression, leading to either overexpression or loss of expression, both of which take place in tumor cells, may have dramatic effects on tumor cell invasion.

Syndecan-2 mediates adhesion and proliferation of colon carcinoma cells

Syndecan-2 is a transmembrane heparan sulfate proteoglycan whose function at the cell surface is unclear. In this study, we examined the function of syndecan-2 in colon cancer cell lines. In several colon cancer cell lines, syndecan-2 was highly expressed compared with normal cell lines. In contrast, syndecan-1 and -4 were decreased. Cell biological studies using the extracellular domain of recombinant syndecan-2 (2E) or spreading assay with syndecan-2 antibody-coated plates showed that syndecan-2 mediated adhesion and cytoskeletal organization of colon cancer cells. This interaction was critical for the proliferation of colon carcinoma cells. Blocking with 2E or antisense syndecan-2 cDNA induced G(0)/G(1) cell cycle arrest with concomitantly increased expression of p21, p27, and p53. Furthermore, blocking of syndecan-2 through antisense syndecan-2 cDNA significantly reduced tumorigenic activity in colon carcinoma cells. Therefore, increased syndecan-2 expression appears to be a critical for colon carcinoma cell behavior, and syndecan-2 regulates tumorigenic activity through regulation of adhesion and proliferation in colon carcinoma cells.

Reduced expression of syndecan-1 affects metastatic potential and clinical outcome in patients with colorectal cancer

Syndecan-1 is a transmembrane heparansulfate proteoglycan which regulates cell-to-cell or cell-to-extracellular matrix interactions and may influence malignant cell behavior. We investigated the alterations of syndecan-1 expressions in colorectal cancers and analyzed the relationship between histological and clinical characteristics. Syndecan-1 protein expression in colorectal cancer tissues was investigated with immunohistochemical staining of resected specimens. In situ hybridization was performed using syndecan-1 riboprobe to confirm the transcriptional signals. Syndecan-1 mRNA expression in cancer cell lines cultured with or without methylation inhibitor was also analyzed by quantitative PCR. Out of 105 specimens tested, less than 25% of tumor cells were stained with anti-syndecan-1 monoclonal antibody in 36 (34.3%). In situ hybridization showed a similar staining profile to that of immunohistochemistry. Syndecan-1 mRNA expression was increased by the methylation inhibitor 5-aza-2'-deoxycytidine, suggesting that the hypermethylation is involved in the suppression of syndecan-1 expression. Clinically, the incidence of metastasis to lymphnode or liver in patients with syndecan-1-negative tumors was significantly high. Among T1 colorectal cancers displaying a primary invasive phase, lymphnode metastasis, undifferentiated characters and 'budding' of cancer cells were more common in syndecan-1-negative tumors. The survival rate in patients with syndecan-1-negative tumors was decreased significantly in a stage-independent manner. These results suggest that the reduction of syndecan-1 expression in colorectal cancer cells, which is supposed to be regulated at the transcription level, is closely related to invasive character. The evaluation of syndecan-1 expression in colorectal cancer may allow prediction of patients' survival after surgery.

Gros1, a potential growth suppressor on chromosome 1: its identity to basement membrane-associated proteoglycan, leprecan

By immunoscreening with an antibody raised against a plasma membrane protein, we have cloned a growth suppressor gene, Gros1 and assigned it to short arm of human chromosome 1. Two alternatively spliced forms of the gene encoding 84- and 41-kDa (carboxy-terminus truncated) proteins were cloned. The two transcripts, 4.4 and 2.7 kb, were expressed weakly in most of the human tissues, with a high expression of the smaller transcript in placenta, ovary and testis. Normal human fibroblasts in culture showed two transcripts, with a higher level of expression of the 4.4 kb transcript. Transformed cells on the other hand showed predominant expression of the 2.7 kb transcript. Two Gros1 transcripts were also detected in most of the mouse tissues. Stable transfection of the mouse cDNA encoding the 85-kDa protein into NIH3T3 cells resulted in their slow growth and reduced colony-forming efficiency. Stable clones expressing antisense RNA on the other hand exhibited higher colony forming efficiency. While our data implied that Gros1 is a novel growth suppressor gene on human chromosome 1, an independent study has recently characterized its rat-homolog as a leucine proline-enriched novel basement membrane-associated proteoglycan leprecan. We describe here cloning, expression and biological activity analysis implying that this novel proteoglycan is a potential growth suppressor on chromosome 1p31, frequently altered in many malignancies.