A subset of high Gleason grade prostate carcinomas contain a large burden of prostate cancer syndecan-1 positive stromal cells

Glycosylation Changes in Prostate Cancer Progression

Prostate Cancer (PCa) is the most commonly diagnosed malignancy and second leading cause of cancer-related mortality in men. With the use of next generation sequencing and proteomic platforms, new biomarkers are constantly being developed to both improve diagnostic sensitivity and specificity and help stratify patients into different risk groups for optimal management. In recent years, it has become well accepted that altered glycosylation is a hallmark of cancer progression and that the glycan structures resulting from these mechanisms show tremendous promise as both diagnostic and prognostic biomarkers. In PCa, a wide range of structural alterations to glycans have been reported such as variations in sialylation and fucosylation, changes in branching, altered levels of Lewis and sialyl Lewis antigens, as well as the emergence of high mannose "cryptic" structures, which may be immunogenic and therapeutically relevant. Furthermore, aberrant expression of galectins, glycolipids, and proteoglycans have also been reported and associated with PCa cell survival and metastasis. In this review, we discuss the findings from various studies that have explored altered N- and O-linked glycosylation in PCa tissue and body fluids. We further discuss changes in O-GlcNAcylation as well as altered expression of galectins and glycoconjugates and their effects on PCa progression. Finally, we emphasize the clinical utility and potential impact of exploiting glycans as both biomarkers and therapeutic targets to improve our ability to diagnose clinically relevant tumors as well as expand treatment options for patients with advanced disease.

Syndecan Family Gene and Protein Expression and Their Prognostic Values for Prostate Cancer

Prostate cancer (PCa) is the leading cause of cancer-associated mortality in men, and new biomarkers are still needed. The expression pattern and protein tissue localization of proteoglycans of the syndecan family (SDC 1-4) and syntenin-1 (SDCBP) were determined in normal and prostatic tumor tissue from two genetically engineered mouse models and human prostate tumors. Studies were validated using SDC 1-4 and SDCBP mRNA levels and patient survival data from The Cancer Genome Atlas and CamCAP databases. RNAseq showed increased expression of Sdc1 in Pb-Cre4/Pten^f/f mouse Pca and upregulation of Sdc3 expression and downregulation of Sdc2 and Sdc4 when compared to the normal prostatic tissue in Pb-Cre4/Trp53^f/f-;Rb1^f/f mouse tumors. These changes were confirmed by immunohistochemistry. In human PCa, SDC 1-4 and SDCBP immunostaining showed variable localization. Furthermore, Kaplan-Meier analysis showed that patients expressing SDC3 had shorter prostate-specific survival than those without SDC3 expression (log-rank test, p = 0.0047). Analysis of the MSKCC-derived expression showed that SDC1 and SDC3 overexpression is predictive of decreased biochemical recurrence-free survival (p = 0.0099 and p = 0.045, respectively), and SDC4 overexpression is predictive of increased biochemical recurrence-free survival (p = 0.035). SDC4 overexpression was associated with a better prognosis, while SDC1 and SDC3 were associated with more aggressive tumors and a worse prognosis.

Syndecan-1 (CD138), Carcinomas and EMT

Cell surface proteoglycans are known to be important regulators of many aspects of cell behavior. The principal family of transmembrane proteoglycans is the syndecans, of which there are four in mammals. Syndecan-1 is mostly restricted to epithelia, and bears heparan sulfate chains that are capable of interacting with a large array of polypeptides, including extracellular matrix components and potent mediators of proliferation, adhesion and migration. For this reason, it has been studied extensively with respect to carcinomas and tumor progression. Frequently, but not always, syndecan-1 levels decrease as tumor grade, stage and invasiveness and dedifferentiation increase. This parallels experiments that show depletion of syndecan-1 can be accompanied by loss of cadherin-mediated adhesion. However, in some tumors, levels of syndecan-1 increase, but the characterization of its distribution is relevant. There can be loss of membrane staining, but acquisition of cytoplasmic and/or nuclear staining that is abnormal. Moreover, the appearance of syndecan-1 in the tumor stroma, either associated with its cellular component or the collagenous matrix, is nearly always a sign of poor prognosis. Given its relevance to myeloma progression, syndecan-1-directed antibody—toxin conjugates are being tested in clinical and preclinical trials, and may have future relevance to some carcinomas.

Increased Cytoplasmic CD138 Expression Is Associated with Aggressive Characteristics in Prostate Cancer and Is an Independent Predictor for Biochemical Recurrence

Syndecan-1 (CD138) is a transmembrane proteoglycan expressed in various normal and malignant tissues. It is of interest due to a possible prognostic effect in tumors and its role as a target for the antibody-drug conjugate indatuximab ravtansine. Here, we analyzed 17,747 prostate cancers by immunohistochemistry. Membranous and cytoplasmic CD138 staining was separately recorded. In normal prostate glands, CD138 staining was limited to basal cells. In cancers, membranous CD138 positivity was seen in 19.6% and cytoplasmic CD138 staining in 11.2% of 12,851 interpretable cases. A comparison with clinico-pathological features showed that cytoplasmic CD138 staining was more linked to unfavorable tumor features than membranous staining. Cytoplasmic CD138 immunostaining was associated with high tumor stage (p < 0.0001), high Gleason grade (p < 0.0001), nodal metastases (p < 0.0001), positive surgical margin (p < 0.0001), and biochemical recurrence (p < 0.0001). This also holds true for both V-ets avian erythroblastosis virus E26 oncogene homolog (ERG) fusion positive and ERG fusion negative tumors although the cytoplasmic CD138 expression was markedly more frequent in ERG positive than in ERG negative tumors (p < 0.0001). Comparison with 11 previously analyzed chromosomal deletions identified a conspicuous association between cytoplasmic CD138 expression and 8p deletions (p < 0.0001) suggesting a possible functional interaction of CD138 with one or several 8p genes. Multivariate analysis revealed the cytoplasmic CD138 expression as an independent prognostic parameter in all cancers and in the ERG positive subgroup. In summary, our study indicates the cytoplasmic CD138 expression as a strong and independent predictor of poor prognosis in prostate cancer. Immunohistochemical measurement of CD138 protein may thus—perhaps in combination with other parameters—become clinically useful in the future.

ADAMTS-15 Has a Tumor Suppressor Role in Prostate Cancer

Extracellular matrix remodeling has emerged as an important factor in many cancers. Proteoglycans, including versican (VCAN), are regulated via cleavage by the proteolytic actions of A Disintegrin-like And Metalloproteinase domain with Thrombospondin-1 motif (ADAMTS) family members. Alterations in the balance between Proteoglycans and ADAMTS enzymes have been proposed to contribute to cancer progression. Here, we analyzed the expression of ADAMTS-15 in human prostate cancer, and investigated the effects of enforced expression in prostate cancer cell lines. ADAMTS-15 was found to be expressed in human prostate cancer biopsies with evidence of co-localization with VCAN and its bioactive cleavage fragment versikine. Enforced expression of ADAMTS-15, but not a catalytically-inactive version, decreased cell proliferation and migration of the ‘castrate-resistant’ PC3 prostate cancer cell line in vitro, with survival increased. Analysis of ‘androgen-responsive’ LNCaP prostate cancer cells in vivo in NOD/SCID mice revealed that ADAMTS-15 expression caused slower growing tumors, which resulted in increased survival. This was not observed in castrated mice or with cells expressing catalytically-inactive ADAMTS-15. Collectively, this research identifies the enzymatic function of ADAMTS-15 as having a tumor suppressor role in prostate cancer, possibly in concert with androgens, and that VCAN represents a likely key substrate, highlighting potential new options for the clinic.

Syndecan-1 in the Tumor Microenvironment

Syndecan-1 along with the other three syndecan proteins is present in the varied components of the tumor microenvironment: fibroblasts, inflammatory tumor immunity-associated cells, vessels, and extracellular matrix. Epithelial and non-epithelial tumors may show stromal syndecans. The main relevance of stromal syndecans as tumor biomarker resides in the relationships to tumor features such as type and differentiation as well as to prognosis.

Prevalence of Syndecan-1 (CD138) Expression in Different Kinds of Human Tumors and Normal Tissues

Syndecan-1 (CD138) is a transmembrane proteoglycan known to be expressed in various normal and malignant tissues. It is of interest because of a possible prognostic role of differential expression in tumors and its role as a target for indatuximab, a monoclonal antibody coupled with a cytotoxic agent. To comprehensively analyze CD138 in normal and neoplastic tissues, we used tissue microarrays (TMAs) for analyzing immunohistochemically detectable CD138 expression in 2,518 tissue samples from 85 different tumor entities and 76 different normal tissue types. The data showed that CD138 expression is abundant in tumors. At least an occasional weak CD138 immunostaining could be detected in 71 of 82 (87%) different tumor types, and 58 entities (71%) had at least one tumor with a strong positivity. In normal tissues, a particularly strong expression was found in normal squamous epithelium of various organs, goblet and columnar cells of the gastrointestinal tract, and in hepatocytes. The highly standardized analysis of most human cancer types resulted in a ranking order of tumors according to the frequency and levels of CD138 expression. CD138 immunostaining was highest in squamous cell carcinomas such as from the esophagus (100%), cervix uteri (79.5%), lung (85.7%), vagina (89.7%) or vulva (73.3%), and in invasive urothelial cancer (76.2%). In adenocarcinomas, CD138 was also high in lung (82.9%) and colorectal cancer (85.3%) but often lower in pancreas (73.3%), stomach (54.2% in intestinal type), or prostate carcinomas (16.3%). CD138 expression was usually low or absent in germ cell tumors, sarcomas, endocrine tumors including thyroid cancer, and neuroendocrine tumors. In summary, the preferential expression in squamous cell carcinomas of various sites makes these cancers prime targets for anti-CD138 treatments once these might become available. Abundant expression in many different normal tissues might pose obstacles to exploiting CD138 as a therapeutic target, however.

A shift from membranous and stromal syndecan-1 (CD138) expression to cytoplasmic CD138 expression is associated with poor prognosis in breast cancer

Syndecan-1 (CD138) is a transmembrane proteoglycan expressed in normal and malignant tissues. It is of interest because of a possible prognostic effect in tumors and as a target for Indatuximab, a monoclonal antibody coupled to a cytotoxic agent. To assess the prognostic role of CD138 expression in breast cancer (BCa), a tissue microarray containing 1535 BCa specimens was analyzed by immunohistochemistry. Cytoplasmic, membranous, and stromal CD138 staining was separately analyzed. In normal breast tissue, CD138 staining was limited to epithelial cell membranes. In cancers, membranous staining tended to become weaker or even disappeared (38.3% of cancers with absence of membranous staining) but cytoplasmic and stromal staining newly appeared in 29.7% and 58.1% of cancers. Loss of membranous epithelial CD138 staining as well as presence of cytoplasmic and stromal CD138 positivity were-to a variable degree-associated with high pT, high grade, nodal metastasis, estrogen receptor-negative, progesterone receptor-negative, human epidermal growth factor receptor 2+, and poor overall patient survival. A combined analysis of epithelial and stromal CD138 expression revealed a link to overall patient survival (P < .0001) with best prognosis for patients with stromal positivity and absence of cytoplasmic staining, the worst prognosis for cancers with cytoplasmic staining and stromal negativity and intermediate prognosis for patients having either cytoplasmic staining or stromal negativity. In multivariate analyses, CD138 was not independent of established prognostic features. In summary, these data reveal a compartment depending prognostic effect of CD138 expression in BCa with cytoplasmic positivity being linked to aggressive cancer and stromal CD138 being linked to a more favorable prognosis.

Glycans as Biomarkers in Prostate Cancer

Prostate cancer is the most commonly diagnosed malignancy in men, claiming over350,000 lives worldwide annually. Current diagnosis relies on prostate-specific antigen (PSA)testing, but this misses some aggressive tumours, and leads to the overtreatment of non-harmfuldisease. Hence, there is an urgent unmet clinical need to identify new diagnostic and prognosticbiomarkers. As prostate cancer is a heterogeneous and multifocal disease, it is likely that multiplebiomarkers will be needed to guide clinical decisions. Fluid-based biomarkers would be ideal, andattention is now turning to minimally invasive liquid biopsies, which enable the analysis oftumour components in patient blood or urine. Effective diagnostics using liquid biopsies willrequire a multifaceted approach, and a recent high-profile review discussed combining multipleanalytes, including changes to the tumour transcriptome, epigenome, proteome, and metabolome.However, the concentration on genomics-based paramaters for analysing liquid biopsies ispotentially missing a goldmine. Glycans have shown huge promise as disease biomarkers, anddata suggests that integrating biomarkers across multi-omic platforms (including changes to theglycome) can improve the stratification of patients with prostate cancer. A wide range ofalterations to glycans have been observed in prostate cancer, including changes to PSAglycosylation, increased sialylation and core fucosylation, increased O-GlcNacylation, theemergence of cryptic and branched N-glyans, and changes to galectins and proteoglycans. In thisreview, we discuss the huge potential to exploit glycans as diagnostic and prognostic biomarkersfor prostate cancer, and argue that the inclusion of glycans in a multi-analyte liquid biopsy test forprostate cancer will help maximise clinical utility.

Comparison of Syndecan-1 Immunohistochemical Expression in Lobular and Ductal Breast Carcinoma with Nodal Metastases

Syndecan-1 (Sdc1) is a transmembrane heparan sulfate proteoglycan, an extracellular matrix receptor involved in intercellular communication, proliferation, angiogenesis, and metastasis. This study determined and compared Sdc1 expression in the tumor cells and stroma of 30 invasive lobular and 30 invasive ductal breast carcinomas (ILCs/IDCs), also in the axillary node metastases of ductal type, and correlated it with clinical and tumor parameters. Sdc1 was expressed in the epithelium of 90% carcinoma of both histological types. Also, it was most frequently expressed in their tumor stroma, but in ILC, stromal expression was negative in 40%. Sdc1 was expressed in 86.7% of the metastatic epithelium of IDC nodal metastases (in even 50% as high expression), while the nodal stroma was negative in 46.7%. Primary IDC showed a negative correlation between epithelial Sdc1 and progesterone receptors (PRs), whereas ILC showed a positive correlation between stromal Sdc1 and histological gradus. In the metastatic epithelium, Sdc1 was negatively correlated with a patient's age, estrogen receptors (ERs), and PRs in the primary tumors, while the stroma of metastases demonstrated a positive correlation with the focus number in primary tumors and a negative correlation with PRs in primary tumors. This research revealed identical overall epithelial Sdc1 expression in both breast carcinomas with no statistically significant difference in its stromal expression and confirmed the role of Sdc1 in the progression of both tumor types and in the development of ductal carcinoma's metastatic potential.

Decline in arylsulfatase B expression increases EGFR expression by inhibiting the protein-tyrosine phosphatase SHP2 and activating JNK in prostate cells

Epidermal growth factor receptor (EGFR) has a crucial role in cell differentiation and proliferation and cancer, and its expression appears to be up-regulated when arylsulfatase B (ARSB or GalNAc-4-sulfatase) is reduced. ARSB removes 4-sulfate groups from the nonreducing end of dermatan sulfate and chondroitin 4-sulfate (C4S), and its decreased expression has previously been reported to inhibit the activity of the ubiquitous protein-tyrosine phosphatase, nonreceptor type 11 (SHP2 or PTPN11). However, the mechanism by which decline in ARSB leads to decline in SHP2 activity is unclear. Here, we show that SHP2 binds preferentially C4S, rather than chondroitin 6-sulfate, and confirm that SHP2 activity declines when ARSB is silenced. The reduction in ARSB activity, and the resultant increase in C4S, increased the expression of EGFR (Her1/ErbB1) in human prostate stem and epithelial cells. The increased expression of EGFR occurred after 1) the decline in SHP2 activity, 2) enhanced c-Jun N-terminal kinase (JNK) activity, 3) increased nuclear DNA binding by c-Jun and c-Fos, and 4) EGFR promoter activation. In response to exogenous EGF, there was increased bromodeoxyuridine incorporation, consistent with enhanced cell proliferation. These findings indicated that ARSB and chondroitin 4-sulfation affect the activation of an important dual phosphorylation threonine-tyrosine kinase and the mRNA expression of a critical tyrosine kinase receptor in prostate cells. Restoration of ARSB activity with the associated reduction in C4S may provide a new therapeutic approach for managing malignancies in which EGFR-mediated tyrosine kinase signaling pathways are active.