Stromal accumulation of chondroitin sulphate in mammary tumours of dogs

Chondroitin Sulfate Disaccharides, a Serum Marker for Primary Serous Epithelial Ovarian Cancer

Glycosaminoglycans are long polysaccharidic chains, which are mostly present in connective tissues. Modified GAG expression in tissues surrounding malignant cells has been shown to contribute to tumor progression, aggressive status and metastasis in many types of cancer. Ovarian cancer is one of the most lethal gynecological malignancies due to its late diagnosis because of the absence of clear symptoms and unavailability of early disease markers. We investigated for the first time GAG changes at the molecular level as a novel biomarker for primary epithelial ovarian cancer. To this end, serum of a cohort of 68 samples was digested with chondroitinase ABC, which releases chondroitin sulfate into disaccharides. After labeling and purification, they were measured by HPLC, yielding a profile of eight disaccharides. We proposed a novel GAG-based score named "CS- bio" from the measured abundance of disaccharides present that were of statistical relevance. CS-bio's performance was compared with CA125, the clinically used serum tumor marker in routine diagnostics. CS-bio had a better sensitivity and specificity than CA125. It was more apt in differentiating early-stage patients from healthy controls, which is of high interest for oncologists.

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

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

Myoepithelial cells in canine mammary tumours

Mammary tumours are the most common neoplasms of female dogs. Compared to mammary tumours of humans and cats, myoepithelial (ME) cell involvement is common in canine mammary tumours (CMT) of any subtype. Since ME cell involvement in CMT influences both histogenetic tumour classification and prognosis, correct identification of ME cells is important. This review describes immunohistochemical methods for identification of canine mammary ME cells used in vivo. In addition, phenotypic and genotypic methods to isolate ME cells for in vitro studies to analyse tumour-suppressor protein production and gene expression are discussed. The contribution of ME cells to both histogenetic classifications and the prognosis of CMT is compared with other species and the potential use of ME cells as a method to identify carcinoma in situ is discussed.

Atypical canine mammary adenoma characterized by cystic ducts comprising a single layer of basaloid cells with myoepithelial differentiation

This report describes an atypical mammary adenoma with a rare histological feature characterized by proliferating single-layered cystic ducts composed of basaloid cells with frequent myoepithelial differentiation. A 9-year-old, intact female Miniature Pinscher dog had mammary tumors on the thorax. Histologically, one of tumors comprised the proliferation of two types of tubular structures; the single-layered cystic ducts lined by flattened cells and double-layered tubules with luminal cells and outer spindle cells. The former ducts were predominant in the tumor and contained pale basophilic mucus, which was Alcian blue (pH 2.5)-positive, but periodic acid Schiff-negative. Immunohistochemical staining indicated that the cells lining single-layered cystic ducts were negative for the luminal epithelial marker, cytokeratin (CK) CAM5.2, but were constantly positive for basal cell markers CK14 and p63 and frequently positive for SMA. Electron microscopy revealed fine, parallel myofilaments within these single-layered neoplastic cells. These histological and immunohistological examinations suggested that the origin of the tumor was bipotential mammary progenitor cells with predominant differentiation into the myoepithelial progenitor linage.

Canine mammary mixed tumours: a review

Mammary mixed tumours are the most frequent neoplasias in female dogs. In humans, mixed tumours are frequently found in the salivary glands and are known as pleomorphic adenomas. In addition to their histomorphologic similarities, mixed tumours and pleomorphic adenomas have the potential to become malignant and give rise to carcinomas in mixed tumours and carcinomas ex-pleomorphic adenoma, respectively. The factors associated with malignant transformation are still poorly known in the case of canine mixed tumours. However, this form of neoplasia tends to be associated with a better prognosis than other malignant histological types. This paper discusses the main features associated with female canine mammary mixed tumours.

Protocol, pattern and paper: interactive stabilization of immunohistochemical knowledge

This paper analyzes the investigation of the distribution of the protein tenascin-C in canine mammary tumors. The method involved immunohistochemistry of tissue slices, performed by the application of an antibody to tenascin-C that specifically can be made visible for microscopic inspection. The first phase of the project is the making of the protocol, the second the deduction of a pattern of tenascin-C distribution in tumors and the third the writing of a paper. Each of the phases is analyzed separately, using the concept of resistance and accommodation. My purpose is to show that in each phase of the process of producing knowledge, the scientist meets resistances which force him to accommodate by changing his conceptual, technical and methodological approaches. In reverse, the details of the non-human agent (protocol, pattern or paper) have to be accommodated to the wishes and expectations of the scientist. Through this interaction a situation of stability of knowledge is reached at the end of each phase. In the protocol phase, resistance is found in the antibody and tissue slices. In the phase of pattern deduction the resistance is in the pathological diagnosis of the tumors and the expectations and hypothesis with which the scientist had entered the project; in the criteria to be used for assigning the slices to a tenascin-C pattern; and in the responses of colleagues and supervisor. In the paper-writing phase the interaction is between the scientist and the scientific community which should take on board the knowledge from the research project. When stabilization of knowledge is obtained in one of the phases, the agents of resistance turn into allies in the next phase, giving support to accommodating the resistances in this later phase. Second, the stabilization of knowledge of the protocol is further enhanced when stabilization of the pattern is achieved; in addition, knowledge of the pattern is more definite when it has become stabilized and closed knowledge within the science community.

Expression of versican in relation to chondrogenesis-related extracellular matrix components in canine mammary tumors

Versican plays a role in tumor cell proliferation and adhesion and may also regulate cell phenotype. Furthermore, it is one of the pivotal proteoglycans in mesenchymal condensation during prechondrogenesis. We have previously demonstrated accumulation of versican protein in myoepithelial-like spindle cell proliferations and myxoid tissues of complex and mixed mammary tumors of dogs. The objective of this study was to investigate whether the high expression of versican relates to prechondrogenesis in these tissues. Therefore, we aimed to identify cartilage markers, such as collagen type II and aggrecan both at mRNA and protein level in relation to versican. The neopitope of chondoitin-6-sulphate (3B3) known to be generated in developing cartilage has been investigated by immunohistochemisty and a panel of antibodies were used to characterize the phenotype of cells that are involved in cartilage formation. In addition, co-localization of versican with hyaluronan and link protein was studied. RT-PCR revealed upregulation of genes of versican, collagen type II and aggrecan in neoplastic tissues, especially in complex and mixed tumors. Immunohistochemistry showed the expression of cartilage biomarkers not only in the cartilagenous tissues of mixed tumors, but also in myoepitheliomas and in the myoepithelial-like cell proliferations and myxoid areas of complex and mixed tumors. The results show the cartilagenous differentiation of complex tumors and myoepitheliomas and indicate that the myxoid tissues and myoepithelial-like cell proliferations are the precursor tissues of the ectopic cartilage in mixed tumors. Furthermore, we suggest that cartilage formation in canine mammary tumors is a result of (myo)epithelial to mesenchymal transition.

Prognostic and predictive markers in canine tumours: rationale and relevance. A review

Cancer is one of the most common causes of death in dogs. The availability of multiple treatment modalities and novel therapeutic targets make the correct diagnosis, prognostic stratification, and the identification of treatment effect predictive factors an issue of major debate in cancer management. Selection of high and low risk patients and the type of systemic or local treatment is important in cancer management. The search for better prognostic markers and predictive factors is now focused on the molecular mechanisms which underlie tumour behaviour, such as altered cell cycle progression, proliferation, apoptosis, and angiogenesis. The ultimate goal is to identify reliable markers that can accurately diagnose and stage a tumour and predict tumour's clinical behaviour, prognosis and response to therapy. In this review, the current state of prognostication in canine tumours and promising new molecular markers are discussed. The markers are allocated to four groups according to their function: (i) proliferation markers, (ii) apoptosis, (iii) extracellular matrix and cell adhesion molecules, (iv) angiogenesis and (v) cell cycle regulators. Clinicopathological factors and histopathological grading remain the most practical parameters in decision-making. Although experimental research has shown that molecular markers have a good potential to be used as diagnostic, prognostic or predictive markers in canine tumours, insufficient evidence exists on their efficacy for routine use in veterinary oncology.

Versican and hyaluronan expression in canine colonic adenomas and carcinomas: relation to malignancy and depth of tumour invasion

Changes in the production and structure of glycosaminoglycans and proteoglycans have been reported in many neoplastic tissues, and versican and hyaluronan (extracellular matrix components) are frequently increased in tumours and promote tumour progression. The distribution of chondroitin sulphate, versican and hyaluronan in normal canine colonic wall (n=10), and normal colonic lymph nodes (n=10), colonic adenomas (n=22), colonic adenocarcinomas (n=28), colonic undifferentiated carcinomas (n=7), and colonic lymph node metastases (n=8), was examined, with antibodies against chondroitin sulphate and versican, and a specific biotinylated probe for hyaluronan. The epithelial cells of the normal colonic mucosa were negative for all three substances, whereas the stromal tissue and lamina propria were moderately positive for chondroitin sulphate and hyaluronan, and weakly positive for versican. Chondroitin sulphate expression was increased in adenomas and carcinomas. However, there was no significant correlation between grade of tumour and degree of chondroitin sulphate expression. Versican expression was increased in the peritumoral stroma of adenocarcinomas and reduced in adenomas. A significant correlation was observed between grade of tumour and degree of versican expression. In 13 adenocarcinomas and undifferentiated carcinomas with invasion into all layers of the colorectum, the intensity of stromal versican expression was significantly related to the depth of invasion; the intensity was increased in the stroma of tumour islands in deep layers of the colonic wall. Unlike versican expression, hyaluronan expression was increased in the stromal tissue of both adenomas and carcinomas. However, the degree of stromal hyaluronan expression was unrelated to tumour grade and depth of tumour invasion. Hyaluronan was also expressed in the membrane and in the cytoplasm of tumour cells in 3/22 (14%) adenomas, 18/28 (64%) adenocarcinomas and 2/7 (29%) undifferentiated carcinomas. These results suggest that altered levels of both versican and hyaluronan in canine colonic tumours affect tumour progression.

Tenascin and proteoglycans: the role of tenascin and proteoglycans in canine tumours

Tenascin is a high molecular weight, extracellular matrix glycoprotein, subject to complex spatial and temporal patterns of expression during embryogenesis, wound healing and neoplastic processes. Proteoglycans are complex macromolecules, containing one or more glycosaminoglycans attached to a core protein, which are involved in cell-cell and cell-matrix interaction. Altered expression of both tenascin and proteoglycans has been found in tumours and expression of these two extracellular matrix proteins seems to be modulated in the same way in human and canine tumours. The quantitative and qualitative changes in tenascin and proteoglycan composition may significantly affect behaviour of tumour cells. While tenascin and proteoglycans have many biological functions likely to influence tumour development and progression, their exact role in regulation of tumour cell-cell interaction, proliferation, invasion and metastasis remains to be established. This review focuses on the role of tenascin and proteoglycans in neoplasia and recent developments in canine tumours.

Immunolocalization of the smooth muscle-specific protein calponin in complex and mixed tumors of the mammary gland of the dog: assessment of the morphogenetic role of the myoepithelium

The immunohistochemical expression of the smooth muscle-specific protein calponin was studied to assess the contribution of myoepithelial cells to the histogenesis of spindle cells of complex and mixed tumors of the mammary gland of the dog and the origin of cartilage and bone in mixed tumors. Formalin-fixed tissues from 55 benign and malignant tumors (49 also containing surrounding normal mammary gland) were evaluated. Periacinar and periductal myoepithelial cells of all the 49 normal mammary glands were diffusely stained by the anti-human calponin monoclonal antibody. Calponin was found in 53 (98%) of the tumors studied, reacting with the myoepithelium-like cells of 86% of benign tumors and their remnants in 85% of malignant tumors. Five different types of calponin-immunoreactive myoepithelial cells were identified: hypertrophic myoepithelial cells. fusiform cells, stellate myoepithelial cells, rounded (myoepithelial) cells, and chondroblasts. Differences in staining intensity and staining pattern among these five types of cells suggested a transition of myoepithelial cells to chondroblasts. Stromal myofibroblasts also showed calponin immunoreactivity, but they did not react with a cytokeratin 14 monoclonal antibody, which recognizes myoepithelial cells in mammary gland. Calponin appears to be a very sensitive marker of normal and neoplastic myoepithelium in the canine mammary gland, and its identification in different cell types of complex and mixed tumors of the mammary gland of the dog suggests a major histogenetic role for myoepithelial cells.

Tenascin expression in normal, hyperplastic, dysplastic and neoplastic canine mammary tissues

Mammary tumours are the most common neoplasias of female dogs and may have a complex histological pattern with both epithelial and spindle cells participating in the transformation process. A frequent feature of these tumours is chondroid or bone metaplasia of the extracellular matrix, which mainly occurs in areas of proliferated spindle-shaped cells, probably of myoepithelial origin. The present study evaluates immunohistochemically the expression of tenascin in 186 surgical samples of canine mammary tissues, ranging from normality to neoplasia. Tenascin was present in all mammary tissues studied, with an increased expression in remodelling situations and in neoplastic lesions. Basement membrane was the most frequently labelled structure, but stromal tissue was more often and widely labelled in neoplastic lesions. The extracellular matrix was positive in solid and anaplastic carcinomas as well as in spindle cell proliferation areas. Tenascin expression in extracellular matrix was also abundant in areas of initial chondroid metaplasia and, with variable extension, in almost all cartilage islands of mixed tumours. In well differentiated secretory areas only apical granules of luminal cells were positive, suggesting a different pattern of tenascin expression during secretory differentiation. The digestion of chondroitin sulphate significantly improved the labelling for tenascin when a co-expression of these two molecules was present. Although our results suggest that tenascin cannot be used as a marker of transformation or of malignancy in canine mammary oncology, it is clear that this molecule plays an important role in proliferation and differentiation processes in the canine mammary gland.

Differences in wound contraction between horses and ponies: the in vitro contraction capacity of fibroblasts

The contribution of wound contraction to wound closure determines the speed of second intention wound healing and it has been shown that significant differences exist with regard to both contraction and inflammatory response between horses and ponies and between various areas of the body. In this study, the contraction capacity of fibroblasts from limbs and buttocks of 4 Dutch Warmblood horses and 4 Shetland ponies was studied in vitro, in order to determine whether differences in wound contraction are due to differences in the inherent contraction capacity of the fibroblasts or to differences in tissue environmental factors, such as the inflammatory response. Fibroblasts were harvested from subcutaneous tissue, cultured and then suspended in both floating and anchored collagen gels. Contraction capacity was assessed by measuring the decrease in area of the floating gels and by measuring the microforces generated in the anchored gels using a custom-built measuring device. In the floating gels, no difference existed in the contraction capacity of fibroblasts from horses and ponies, or from limbs and buttocks. In the anchored gels, no differences existed between horse and pony fibroblasts, but the fibroblasts from the limbs started to contract significantly sooner and produced significantly higher forces than those from the buttocks. It is concluded that the in vivo differences in wound contraction between horses and ponies and between different sites of the body are not caused by differences in the inherent contraction capacity of fibroblasts. The in vitro differences between fibroblasts from limbs and buttocks are thought to be due to the lower proliferation rate and the longer culture time of the fibroblasts originating from the limbs, because mature fibroblasts can develop higher contraction forces than immature fibroblasts. This means that tissue environmental factors, such as cytokine profiles during the inflammatory response, determine the extent of contraction during wound healing. Further research should be directed towards the role of the inflammatory response in wound healing.

Lectin and proteoglycan histochemistry of Merkel cell carcinomas

Changes in carbohydrate residue expression and in proteoglycan distribution occur during different stages of tumor development and progression. However, few data concerning carbohydrate residue analysis as performed by lectin histochemistry and proteoglycan distribution of Merkel cell carcinoma, a rare malignant tumor of the skin, have been reported. Hence, lectin- and proteoglycan immunohistochemistry was performed on paraffin wax material of 9 cases of Merkel cell carcinomas characterized by cytokeratin and neurofilament immunohistochemistry. The lectin binding pattern of tumor cells varied between lectins with different sugar binding specificities, while within a given nominal sugar specificity intensities were remarkably similar between tumors from different patients. The most intensive reaction was observed using Con A (mannose/glucose-specific) followed by LCA with the same specificity and the N-Acetyl glucosamine-specific lectins (WGA, UDA, CMA), while no fucose binding sites were detected (UEA-I). In addition, N-Acetyl galactosamine residues were only occasionally detected. The lectin binding pattern of Merkel cell carcinoma cells indicated that predominantly N-linked glycans and not O-linked glycans, typical for mucins of most epithelia, were present. Hence these tumor cells were relatively undifferentiated and resembled stem cells more closely than differentiated epithelia. The tumor stroma was especially evaluated in this study and showed a lectin reaction, which was intermediate between the tumor cells and extra-tumoral stroma. For example, the reactions of N-Acetyl galactosamine-specific lectins were intensive in the extra-tumoral stroma but nearly negative in tumor cells, while the lectin reaction of the intra-tumoral stroma was similar to the cellular reaction. These results indicated an influence of tumor cells on the stromal constituents. Antibodies against chondroitin type glycosaminoglycans reacted with the tumor stroma and the pericellular substance around the tumor cells most intensely in - and around the major tumor septae which, in general, were well vascularized. The most intensive immunoreactivity was detected using the chondroitin-6-sulfate antibody. The cellular and membrane-associated reaction for heparan sulfate was less intensive in comparison to epidermal cells. In conclusion the pattern of lectin-binding sites, the high chondroitin(sulfate) specific reactivity and the relatively low intensity of heparan sulfate immunohistochemistry indicate a low degree of differentiation and high malignity of the tumors, which is consistent with the clinical behavior of Merkel cell carcinomas.