A quantitative co-localization analysis of large unspliced tenascin-C(L) and laminin-5/gamma2-chain in basement membranes of oral squamous cell carcinoma by confocal laser scanning microscopy

Invasion-Associated Reorganization of Laminin 332 in Oral Squamous Cell Carcinomas: The Role of the Laminin γ2 Chain in Tumor Biology, Diagnosis, and Therapy

Simple Summary

The destructive growth of carcinomas is associated with crossing the border between the epithelial and the connective tissue parts of an organ. One component of this borderline, the basement membrane, is the heterotrimeric laminin 332, which mediates the adhesion of basal epithelial cells. This protein, in particular its gamma 2 chain, is fundamentally reorganized during tumor cell invasion. Specific deposition patterns of laminin 332 are also present in oral squamous cell carcinomas and have been shown to be of high diagnostic and predictive value. Furthermore, laminin 332 restructuring is associated with important tumor biological processes, e.g., stromal activation, the development of a motile phenotype, and tumor spreading. In this review, current knowledge in the field is summarized and the recommendation to consider laminin 332 as a promising grading and monitoring parameter and as a potential therapeutic target is discussed.

Abstract

Invasion of the connective tissue by carcinoma cells is accompanied by disintegration and reorganization of the hemidesmosomes, which connect the basement membrane to the basal epithelial cells. In terms of mediating the basement membrane, i.e., basal cell interactions, the heterotrimeric laminin 332 is the most important bridging molecule. Due to this distinct function, laminin 332, especially its gamma 2 chain, came into the focus of cancer research. Specific de novo synthesis and deposition patterns of laminin 332 are evident upon development and progression of oral squamous cell carcinomas (OSCCs). Loss from the basement membrane, cytoplasmic accumulation, and extracellular deposition are associated with crucial processes such as stromal activation and immune response, epithelial to mesenchymal transition, and tumor cell budding. In networks with components of the tumor microenvironment, altered expression of laminin 332 chains, proteolytic processing, and interaction with integrin receptors seem to promote cancer cell migration. Indeed, reorganization patterns are shown to have a high diagnostic and prognostic value. Here, we summarize the current knowledge on laminin 332 reorganization in OSCCs with special focus on its gamma 2 chain and provide, based on the current literature, evidence on its promising role as a grading and monitoring parameter and as a potential therapeutic target.

Tenascin-C: Form versus function

Tenascin-C is a large, multimodular, extracellular matrix glycoprotein that exhibits a very restricted pattern of expression but an enormously diverse range of functions. Here, we discuss the importance of deciphering the expression pattern of, and effects mediated by, different forms of this molecule in order to fully understand tenascin-C biology. We focus on both post transcriptional and post translational events such as splicing, glycosylation, assembly into a 3D matrix and proteolytic cleavage, highlighting how these modifications are key to defining tenascin-C function.

Spatial organization of the tenascin-C microenvironment in experimental and human cancer

The extracellular matrix (ECM) molecule tenascin-C (TNC) promotes tumor progression. This has recently been demonstrated in the stochastic murine RIP1-Tag2 insulinoma model, engineered to either express TNC abundantly or to be devoid of TNC. However, our knowledge about organization of the TNC microenvironment is scant. Here we determined the spatial distribution of TNC together with other ECM molecules in murine RIP1-Tag2 insulinoma and human cancer tissue (insulinoma and colorectal carcinoma). We found that TNC is organized in matrix tracks together with other ECM molecules of the AngioMatrix signature, a previously described gene expression profile that characterizes the angiogenic switch. Moreover, stromal cells including endothelial cells, fibroblasts and leukocytes were enriched in the TNC tracks. Thus, TNC tracks may provide niches for stromal cells and regulate their behavior. Given similarities of TNC rich niches for stromal cells in human insulinoma and colon cancer, we propose that the RIP1-Tag2 model may be useful for providing insights into the contribution of the tumor stroma specific ECM as promoter of cancer progression.

A novel method for in vivo visualization of the microcirculation of the mandibular periosteum in rats

OBJECTIVE

The periosteum plays an important role in bone physiology, but observation of its microcirculation is greatly limited by methodological constraints at certain anatomical locations. This study was conducted to develop a microsurgical procedure which provides access to the mandibular periosteum in rats.

METHODS

Comparisons of the microcirculatory characteristics with those of the tibial periosteum were performed to confirm the functional integrity of the microvasculature. The mandibular periosteum was reached between the facial muscles and the anterior surface of the superficial masseter muscle at the external surface of the mandibular corpus; the tibial periosteum was prepared by dissecting the covering muscles at the anteromedial surface. Intravital fluorescence microscopy was used to assess the leukocyte-endothelial interactions and the RBCV in the tibial and mandibular periosteum. Both structures were also visualized through OPS and fluorescence CLSM.

RESULTS

The microcirculatory variables in the mandibular periosteum proved similar to those in the tibia, indicating that no microcirculatory failure resulted from the exposure technique.

CONCLUSION

This novel surgical approach provides simple access to the mandibular periosteum of the rat, offering an excellent opportunity for investigations of microcirculatory manifestations of dentoalveolar and maxillofacial diseases.

Tenascin-C and carcinoma cell invasion in oral and urinary bladder cancer

Carcinoma invasion is a complex process regulated by genetic and epigenetic factors as well. A relevant supportive condition for cancer cell migration is the reorganization of the extracellular matrix (ECM), which is realized in an orchestrated multicellular manner including carcinoma cells and stromal fibroblasts. An important key player in the process of ECM reorganization is Tenascin-C (Tn-C). The molecule occurs as different isoforms generated by alternative splicing and de novo glycosylation. Large variants of Tn-C are abundantly re-expressed in the invasive front of many carcinoma types. A special role for initiating migration and accompanied epithelial to mesenchymal transition has been suggested. Here, we review the current knowledge concerning the tumor biological importance of Tn-C, the synthesis and alternative splicing during the invasive process in general, and give an overview on the impact of Tn-C in urothelial carcinoma of the urinary bladder (UBC) and oral squamous cell carcinoma (OSCC).

Molecular changes in invasive front of oral cancer

Treatment planning for oral squamous cell carcinoma (OSCC) is based on the clinical TNM (Tumor, Node and Metastasis) classification. This system operates on the assumption that small tumours without clinical spread have a better prognosis than larger tumours with metastases. However, it is a well-known fact that some tumours with the same clinical staging show different growth patterns and clinical behaviour. This makes the prognosis for patients with OSCC difficult to predict on the basis of clinical staging alone. Although many histopathological characteristics of OSCC have been identified as prognostic factors, none is believed to be completely infallible. Therefore, a great need exists for more reliable prognostic markers, which will assist in treatment decisions. It is now well documented that several molecular events of significance for tumour spread, such as gain and loss of adhesion molecules, secretion of proteolytic enzymes, increased cell proliferation and initiation of angiogenesis occur at the tumour–host interface or invasive front, where the deepest and presumably most aggressive cells reside. This review describes the various molecular events and interactions, which take place in the invasive front of the OSCC, and elucidates their role as prognostic markers.

De novo expression of fetal ED-A(+) fibronectin and B (+) tenascin-C splicing variants in human cardiac allografts: potential impact for targeted therapy of rejection

Management of acute and especially chronic rejection after human cardiac transplantation is still challenging. Chronic rejection, represented by allograft vasculopathy (CAV) and cardiac interstitial fibrosis (CIF) is known to cause severe long-term complications. Rejection associated tissue-remodelling entails the reoccurrence of fetal variants of Fibronectin (Fn) and Tenascin-C (Tn-C), which are virtually absent in adult human organs. In a rat model, an extensive re-expression could be demonstrated for ED-A(+) Fn with spatial association to CAV and CIF. Thus, it is of great interest to investigate the cardiac tissue expression and distribution in human samples. From 48 heart transplanted patients, 64 tissue specimens derived from right ventricular biopsies were available. Histopathological analysis was performed according to the International Society for Heart and Lung Transplantation (ISHLT) guidelines for the detection of acute rejection. By immunohistochemistry, protein expression of ED-A(+) Fn, B(+) Tn-C, alpha-smooth muscle actin, CD31 and CD45 was assessed and analysed semiquantitatively. Co-localisation studies were performed by means of immunofluorescence double labelling. Histopathological analysis of the 64 samples revealed different ISHLT grades (0R in 36 cases, 1R in 20 cases and 2R in 8 cases). There was a distinct and quantitatively relevant re-occurrence of ED-A(+) Fn and B(+) Tn-C in most samples. Semi-quantitative evaluation did not show any correlation to the acute rejection grade for all markers. Interestingly, significant correlations to the extent of inflammation could be shown for ED-A(+) Fn (r = 0.442, p = 0.000) and B(+) Tn-C (r = 0.408, p = 0.001) as well as between both proteins (r = 0.663, p = 0.000). A spatial association of ED-A(+) Fn and B(+) Tn-C to CAV and CIF could be demonstrated. A relevant re-occurrence of ED-A(+) Fn and B(+) Tn-C following human heart transplantation could be demonstrated with spatial association to signs of rejection and a significant correlation to tissue inflammation. These data might contribute to the identification of novel biomarkers reflecting the rejection process and to the development of promising strategies to image, prevent or treat cardiac rejection.

Expression of Wnt-1, TGF-β and related cell-cell adhesion components following radiotherapy in salivary glands of patients with manifested radiogenic xerostomia

BACKGROUND

Radiation-induced xerostomia still represents a common symptom following radiotherapy of head and neck malignancies, which significantly impairs the patient's quality of life. In this cross-sectional study, human salivary glands were investigated to assess the role of Wnt/β-catenin and TGF-β pathways in the pathogenic process of radiogenic impairment of salivary function.

METHODS

Irradiated human salivary glands were investigated in patients with manifested xerostomia. Alteration of Wnt-1 and cell-cell adhesion was evaluated immunohistologically as well as changes in the expression of TGF-β were assessed in salivary gland tissue.

RESULTS

We assessed two alteration patterns in which Wnt-1 expression represents one change along with up-regulation of β-catenin and E-cadherin in irradiated but viable acinar cells. Increased expression of tenascin-C was observed in sites of epithelial-mesenchymal interaction and loss of cell-cell adhesion was assessed in translocated epithelial cells in the stroma.

CONCLUSION

Increased transdifferentiation and remodeling of acinar structures was associated with decrease of viable acinar structures. The role of Wnt and TGF signaling may provide a potential therapeutic approach to prevent radiation-induced damage to salivary glands during radiotherapy for head and neck cancer.

Comparative analysis of oncofetal fibronectin and tenascin-C expression in right atrial auricular and left ventricular human cardiac tissue from patients with coronary artery disease and aortic valve stenosis

Aortic valve stenosis (AVS) and coronary artery disease (CAD) are accompanied by changes in the cardiac extra cellular matrix (cECM) including the re-expression of oncofetal fibronectin (Fn) and tenascin-C (Tn-C) variants. Human antibodies against these variants are usable for targeted therapy. Aim of the study was the comparative analysis of cECM remodelling in tissue samples from right atrial auricle (RAA) and left ventricular septum (LVS). RAA and LVS specimens from 30 patients (17 × AVS; 13 × AVS+CAD) were analysed with respect to histological changes and ECM remodelling using PCR based ECM gene expression profiling. Re-expression of ED-A(+) Fn and A1(+) Tn-C was investigated on the mRNA and on the protein level. For immunofluorescence, human recombinant small immunoprotein (SIP) format antibodies were used. There was a positive correlation of the grade of histological changes in RAA and corresponding LVS samples (r = 0.695). ECM gene expression levels were higher in LVS compared to RAA. For 24 genes, a corresponding relevant (>2.5-fold) up- or down-regulation in RAA and LVS occurred. Using SIP antibodies, a positive correlation of protein deposition levels in RAA and corresponding LVS (r = 0.818) could be shown for ED-A(+) Fn. Cardiac tissue remodelling is likely a process involving the entire heart reflected by intra-individually comparable histology and cECM changes in RAA and LVS samples. ED-A(+) Fn might be an excellent target for an antibody-mediated delivery of diagnostic or therapeutic agents. The RAA is a valuable and representative tool to evaluate cardiac remodelling and to plan individualized therapy.

Oral squamous cell cancer: early detection and the role of alcohol and smoking

Objective

Oral squamous cell carcinoma has a remarkable incidence worldwide and a fairly onerous prognosis, encouraging further research on factors that might modify disease outcome.

Data sources

A web-based search for all types of articles published was initiated using Medline/Pub Med, with the key words such as oral cancer, alcohol consumption, genetic polymorphisms, tobacco smoking and prevention. The search was restricted to articles published in English, with no publication date restriction (last update 2010).

Review Methods

In this review article, we approach the factors for a cytologic diagnosis during OSCC development and the markers used in modern diagnostic technologies as well. We also reviewed available studies of the combined effects of alcohol drinking and genetic polymorphisms on alcohol-related cancer risk.

Results

The interaction of smoking and alcohol significantly increases the risk for aero-digestive cancers. The interaction between smoking and alcohol consumption seems to be responsible for a significant amount of disease.

Conclusion

Published scientific data show promising pathways for the future development of more effective prognosis. There is a clear need for new prognostic indicators, which could be used in diagnostics and, therefore a better selection of the most effective treatment can be achieved.

Immunohistochemical expression of Tenascin in embryogenesis, tumorigenesis and inflammatory oral mucosa

OBJECTIVE

Tenascin is a large extracellular matrix glycoprotein that plays specific role in cell matrix interaction. This protein is mainly attracted because of its oncofetal predominance expression at epithelial-mesenchymal interaction and also been associated with inflammatory response. Thus the aim was to study the expression of Tenascin within the oral cavity in a developing tooth, normal oral mucosa, squamous cell carcinoma and inflammatory mucosa and further to compare its expression in inflammatory mucosa with that of squamous cell carcinoma.

DESIGN

A total numbers of 92 cases were included, with 22 being all morphological stages of developing tooth, 10 cases of normal oral mucosa, 30 cases each of inflammatory gingival hyperplasia and oral squamous cell carcinoma. The intensity and pattern of expression was assessed immunohistochemically using anti-human mouse monoclonal Tenascin antibody.

RESULTS AND CONCLUSION

Tenascin expression in developing tooth was seen mainly at epithelial-mesenchymal junctions, but temporally reduced at cap stage. In normal mucosa TN expression was restricted only at basement membrane zone. Inflammatory gingival hyperplasia intensity of expression was enhanced at the juxtraepithelial stroma and showed reticular pattern of expression. In oral squamous cell carcinoma, intensity of expression was seen in superficial front of the stroma and also around tumour islands with intraepithelial expression and predominantly showed fibrillar pattern of expression. Furthermore, Tenascin expression was noticed around neovascularization. Hence, there is a regulatory system in Tenascin expression and plays a vital role in embryogenesis, tumerogenesis and inflammation in remodelling the stroma for cell migration and also for healing.

EGF/TGFβ1 co-stimulation of oral squamous cell carcinoma cells causes an epithelial-mesenchymal transition cell phenotype expressing laminin 332

Epithelial-mesenchymal transition (EMT) is suggested to be crucial for the development of an invasive and metastatic carcinoma cell phenotype. Therefore, the definition of this phenotype is of great clinical interest. We recently evidenced vimentin positive cells in oral squamous cell carcinoma (OSCC) invasive front expressing laminin γ2 chain mRNA implicating an EMT origin of these cells. To further elucidate the nature of these cells, we have investigated the relation between EMT criteria and laminin-332 expression in a cell culture model of transforming growth factor beta-1 (TGFβ1)/epithelial growth factor (EGF) long time co-stimulation. We demonstrate that in contrast to TGFβ1 or EGF alone, co-stimulation induces phenotype transition in OSCC cells which fulfils the criteria of EMT in terms of vimentin up-regulation and E-cadherin down-regulation on protein level as well as cell scattering. Furthermore, cells displayed a strongly enhanced invasiveness and adhesion to type I-IV collagens. Phenotype transition is accompanied by an enhanced expression of laminin-332, especially of its γ2 chain. We further analyse the expression of extracellular matrix related genes by RT-PCR profiling. With respect to strongly enhanced proteins, data confirm the EMT phenotype of co-stimulated OSCC cells and expression of laminin-332. Furthermore, alpha catenin, collagen type 16, the integrin α7 and β1 chains, and MMP11 are suggested as candidates with potential role in EMT in OSCC. In summary we are able to show that EMT in OSCC is mediated by multiple growth factors and is accompanied by laminin γ2 chain up-regulation evidencing the existence of an intermediate Vim(+) /Ln332(+) EMT phenotype as seen in situ.

A comparative analysis of oncofetal fibronectin and tenascin-C incorporation in tumour vessels using human recombinant SIP format antibodies

Tumour angioneogenesis is associated with the reexpression of oncofetal fibronectin (oncFn) and tenascin-C (oncTn-C) splice variants, which may serve as targets for antibody-based pharmacodelivery. Knowledge of the vascular distribution and organization in different tumours is of importance for the understanding of tumour vessel formation and might be crucial for therapy. Therefore, human SIP format antibodies against Fn ED-A, Fn ED-B and Tn-C A and C splice domains were used for immunofluorescence labelling in renal, lung, oral, colon, breast and urinary bladder carcinoma specimens and in a renal carcinoma xenograft. The spatial relation to stroma, vessels and vascular basement membrane (vBM) was analysed including CD31 and laminin alpha4 chain antibodies. Renal cell carcinomas and atypical carcinoid of the lung revealed vessel-restricted oncFn and/or oncTn-C depositions; all other entities showed a variable stroma positivity including vessels. The individual pattern of oncFn/oncTn-C incorporation in the vBM depended on tumour type, vessel size and intratumoural heterogeneity. There was a stratification of the vessel wall showing luminal oncFn and extraluminal oncTn-C depositions. As shown in the xenograft, perivascular oncTn-C is provided by carcinoma cells. In conclusion, tumours differ in the pattern of Fn or Tn-C isoform positivity in the vessel wall, potentially representing a tumour type specific endothelial cell-tumour cell-stromal cell interaction. Carcinoma cells themselves are involved in vascular Tn-C matrix organization. Up to antigen distribution, Fn and Tn-C domain antibodies may serve as vehicles for antiangiogenetic and antifibrotic agents; oncFn/oncTn-C based targeting should be adapted individually.

The effects of vandetanib on paclitaxel tumor distribution and antitumor activity in a xenograft model of human ovarian carcinoma

This study was designed to determine the effects of vandetanib, a small-molecule receptor tyrosine kinase inhibitor of vascular endothelial growth factor and epidermal growth factor receptor, on paclitaxel (PTX) tumor distribution and antitumor activity in xenograft models of human ovarian carcinoma. Nude mice bearing A2780-1A9 xenografts received daily (5, 10, or 15 days) doses of vandetanib (50 mg/kg per os), combined with PTX (20 mg/kg intravenously). Morphologic and functional modifications associated with the tumor vasculature (CD31 and alpha-smooth muscle actin staining and Hoechst 33342 perfusion) and PTX concentrations in plasma and tumor tissues were analyzed. Activity was evaluated as inhibition of tumor growth subcutaneously and spreading into the peritoneal cavity. Vandetanib treatment produced no significant change in tumor vessel density, although a reduced number of large vessels, an increased percentage of mature vessels, and diminished tumor perfusion were evident. Pretreatment with vandetanib led to decreased tumor PTX levels within 1 hour of PTX injection, although 24 hours later, tumor PTX levels were comparable with controls. In efficacy studies, the combination of vandetanib plus PTX improved antitumor activity compared with vandetanib or PTX alone, with greater effects being obtained when PTX was administered before vandetanib. The combination of PTX plus vandetanib reduced tumor burden in the peritoneal cavity of mice and significantly increased their survival. Analysis of vascular changes and PTX tumor uptake in vandetanib-treated tumors may help to guide the scheduling of vandetanib plus PTX combinations and may have implications for the design of clinical trials with these drugs.

Stromal laminin chain distribution in normal, hyperplastic and malignant oral mucosa: relation to myofibroblast occurrence and vessel formation

BACKGROUND

The contribution of stromal laminin chain expression to malignant potential, tumour stroma reorganization and vessel formation in oral squamous cell carcinoma (OSCC) is not fully understood. Therefore, the expression of the laminin chains alpha2, alpha3, alpha4, alpha5 and gamma2 in the stromal compartment/vascular structures in OSCC was analysed.

METHODS

Frozen tissue of OSCC (9x G1, 24x G2, 8x G3) and normal (2x)/hyperplastic (11x) oral mucosa was subjected to laminin chain and alpha-smooth muscle actin (ASMA) immunohistochemistry. Results were correlated to tumour grade. The relation of laminin chain positive vessels to total vessel number was assessed by immunofluorescence double labelling with CD31.

RESULTS

Stromal laminin alpha2 chain significantly decreases and alpha3, alpha4, alpha5 and gamma2 chains and also ASMA significantly increase with rising grade. The amount of stromal alpha3, alpha4 and gamma2 chains significantly increased with rising ASMA positivity. There is a significant decrease in alpha3 chain positive vessels with neoplastic transformation.

CONCLUSIONS

Mediated by myofibroblasts, OSCC development is associated with a stromal up-regulation of laminin isoforms possibly contributing to a migration promoting microenvironment. A vascular basement membrane reorganization concerning alpha3 and gamma2 chain laminins during tumour angioneogenesis is suggested.

Synergistic effects of cyclic strain and Th1-like cytokines on tenascin-C production by rheumatic aortic valve interstitial cells

Tenascin-C (TN-C) is a key component of extracellular matrix (ECM) and its expression process is poorly understood during rheumatic heart valvular disease (RHVD). In this study, we found that interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha and TN-C concentrations in patients with RHVD were significantly higher than in normal controls. More IFN-gamma receptors and TNF receptors were found being expressed on rheumatic aortic valves interstitial cells than on non-rheumatic ones and their expression was patients' sera dependent. Antibodies neutralizing IFN-gamma or TNF-alpha could attenuate patients' sera-induced TN-C transcription by isolated rheumatic aortic valves interstitial cells. By application with different protein kinase inhibitors, we found that combined with cyclic strain, TNF-alpha and IFN-gamma induced TN-C transcription through the RhoA/ROCK signalling pathway. At the same time, p38 mitogen-activated protein kinase was involved in TNF-alpha and IFN-gamma induced TN-C transcription. TNF-alpha also increased TN-C mRNA level by additional PKC and ERK 1/2 activation. Our finding revealed a new insight into ECM remodelling during RHVD pathogenesis and new mechanisms involved in the clinical anti-IFN-gamma and anti-TNF-alpha therapy.