Involvement of tenascin-C in proliferation and migration of laryngeal carcinoma cells

Biology of Tenascin C and its Role in Physiology and Pathology

Tenascin-C (TNC) is a multimodular extracellular matrix (ECM) protein hexameric with several molecular forms (180-250 kDa) produced by alternative splicing at the pre-mRNA level and protein modifications. The molecular phylogeny indicates that the amino acid sequence of TNC is a well-conserved protein among vertebrates. TNC has binding partners, including fibronectin, collagen, fibrillin-2, periostin, proteoglycans, and pathogens. Various transcription factors and intracellular regulators tightly regulate TNC expression. TNC plays an essential role in cell proliferation and migration. Unlike embryonic tissues, TNC protein is distributed over a few tissues in adults. However, higher TNC expression is observed in inflammation, wound healing, cancer, and other pathological conditions. It is widely expressed in a variety of human malignancies and is recognized as a pivotal factor in cancer progression and metastasis. Moreover, TNC increases both pro-and anti-inflammatory signaling pathways. It has been identified as an essential factor in tissue injuries such as damaged skeletal muscle, heart disease, and kidney fibrosis. This multimodular hexameric glycoprotein modulates both innate and adaptive immune responses regulating the expression of numerous cytokines. Moreover, TNC is an important regulatory molecule that affects the onset and progression of neuronal disorders through many signaling pathways. We provide a comprehensive overview of the structural and expression properties of TNC and its potential functions in physiological and pathological conditions.

TNIIIA2, The Peptide of Tenascin-C, as a Candidate for Preventing Articular Cartilage Degeneration

OBJECTIVE

TNIIIA2 is a peptide of the extracellular matrix glycoprotein tenascin-C. We evaluated whether intra-articular injection of TNIIIA2 could prevent articular cartilage degeneration without inducing synovitis in an osteoarthritis mice model.

DESIGN

Ten micrograms per milliliter of TNIIIA2 were injected into the knee joint of mice (group II) to evaluate the induction of synovitis. The control group received an injection of phosphate buffered saline (group I). Synovitis was evaluated using synovitis score 2 and 4 weeks after injection. The ligaments of knee joints of mice were transected to make the osteoarthritis model. After transection, 10 µg/mL of TNIIIA2 was injected into the knee joint (group IV). The control group received an injection of phosphate buffered saline after transection (group III). Histologic examinations were made using hematoxylin and eosin and safranin-O staining at 2, 4, 8, and 12 weeks postoperatively. An in vitro study was also performed to determine the mechanism by which TNIIIA2 prevents cartilage degeneration. Human chondrocytes were isolated, cultured, and treated with TNIIIA2. The expressions of various mRNAs, including inflammatory cytokines, and anabolic and catabolic factors for cartilage were compared using real-time polymerase chain reaction.

RESULTS

There were no differences between groups in the study of intra-articular injection of mice (group I vs. group II). In the osteoarthritis model, we found development of osteoarthritis was suppressed in group IV at 4 and 8 weeks. TNIIIA2 upregulated the expressions of tumor necrosis factor-α, matrix metalloproteinase 3, and basic fibroblast growth factor.

CONCLUSION

We demonstrated that TNIIIA2 could prevent cartilage degeneration without synovitis.

The Extracellular Matrix Environment of Clear Cell Renal Cell Carcinoma Determines Cancer Associated Fibroblast Growth

Clear cell renal cell carcinoma (ccRCC) is the most common kidney cancer and is often caused by mutations in the oxygen-sensing machinery of kidney epithelial cells. Due to its pseudo-hypoxic state, ccRCC recruits extensive vasculature and other stromal components. Conventional cell culture methods provide poor representation of stromal cell types in primary cultures of ccRCC, and we hypothesized that mimicking the extracellular environment of the tumor would promote growth of both tumor and stromal cells. We employed proteomics to identify the components of ccRCC extracellular matrix (ECM) and found that in contrast to healthy kidney cortex, laminin, collagen IV, and entactin/nidogen are minor contributors. Instead, the ccRCC ECM is composed largely of collagen VI, fibronectin, and tenascin C. Analysis of single cell expression data indicates that cancer-associated fibroblasts are a major source of tumor ECM production. Tumor cells as well as stromal cells bind efficiently to a nine-component ECM blend characteristic of ccRCC. Primary patient-derived tumor cells bind the nine-component blend efficiently, allowing to us to establish mixed primary cultures of tumor cells and stromal cells. These miniature patient-specific replicas are conducive to microscopy and can be used to analyze interactions between cells in a model tumor microenvironment.

Biologically Active TNIIIA2 Region in Tenascin-C Molecule: A Major Contributor to Elicit Aggressive Malignant Phenotypes From Tumors/Tumor Stroma

Tenascin (TN)-C is highly expressed specifically in the lesions of inflammation-related diseases, including tumors. The expression level of TN-C in tumors and the tumor stroma is positively correlated with poor prognosis. However, no drugs targeting TN-C are currently clinically available, partly because the role of TN-C in tumor progression remains controversial. TN-C harbors an alternative splicing site in its fibronectin type III repeat domain, and its splicing variants including the type III-A2 domain are frequently detected in malignant tumors. We previously identified a biologically active region termed TNIIIA2 in the fibronectin type III-A2 domain of TN-C molecule and showed that this region is involved in promoting firm and persistent cell adhesion to fibronectin. In the past decade, through the exposure of various cell lines to peptides containing the TNIIIA2 region, we have published reports demonstrating the ability of the TNIIIA2 region to modulate distinct cellular activities, including survival/growth, migration, and invasion. Recently, we reported that the signals derived from TNIIIA2-mediated β1 integrin activation might play a crucial role for inducing malignant behavior of glioblastoma (GBM). GBM cells exposed to the TNIIIA2 region showed not only exacerbation of PDGF-dependent proliferation, but also acceleration of disseminative migration. On the other hand, we also found that the pro-inflammatory phenotypic changes were promoted when macrophages are stimulated with TNIIIA2 region in relatively low concentration and resulting MMP-9 upregulation is needed to release of the TNIIIA2 region from TN-C molecule. With the contribution of TNIIIA2-stimulated macrophages, the positive feedback spiral loop, which consists of the expression of TN-C, PDGF, and β1 integrin, and TNIIIA2 release, seemed to be activated in GBM with aggressive malignancy. Actually, the growth of transplanted GBM grafts in mice was significantly suppressed via the attenuation of β1 integrin activation. In this review, we thus introduce that the TNIIIA2 region has a significant impact on malignant progression of tumors by regulating cell adhesion. Importantly, it has been demonstrated that the TNIIIA2 region exerts unique biological functions through the extremely strong activation of β1-integrins and their long-lasting duration. These findings prompt us to develop new therapeutic agents targeting the TNIIIA2 region.

Tenascin-C Function in Glioma: Immunomodulation and Beyond

First identified in the 1980s, tenascin-C (TNC) is a multi-domain extracellular matrix glycoprotein abundantly expressed during the development of multicellular organisms. TNC level is undetectable in most adult tissues but rapidly and transiently induced by a handful of pro-inflammatory cytokines in a variety of pathological conditions including infection, inflammation, fibrosis, and wound healing. Persistent TNC expression is associated with chronic inflammation and many malignancies, including glioma. By interacting with its receptor integrin and a myriad of other binding partners, TNC elicits context- and cell type-dependent function to regulate cell adhesion, migration, proliferation, and angiogenesis. TNC operates as an endogenous activator of toll-like receptor 4 and promotes inflammatory response by inducing the expression of multiple pro-inflammatory factors in innate immune cells such as microglia and macrophages. In addition, TNC drives macrophage differentiation and polarization predominantly towards an M1-like phenotype. In contrast, TNC shows immunosuppressive function in T cells. In glioma, TNC is expressed by tumor cells and stromal cells; high expression of TNC is correlated with tumor progression and poor prognosis. Besides promoting glioma invasion and angiogenesis, TNC has been found to affect the morphology and function of tumor-associated microglia/macrophages in glioma. Clinically, TNC can serve as a biomarker for tumor progression; and TNC antibodies have been utilized as an adjuvant agent to deliver anti-tumor drugs to target glioma. A better mechanistic understanding of how TNC impacts innate and adaptive immunity during tumorigenesis and tumor progression will open new therapeutic avenues to treat brain tumors and other malignancies.

Tenascin-C Induces Phenotypic Changes in Fibroblasts to Myofibroblasts with High Contractility through the Integrin αvβ1/Transforming Growth Factor β/SMAD Signaling Axis in Human Breast Cancer

Tenascin-C (TNC) is strongly expressed by fibroblasts and cancer cells in breast cancer. To assess the effects of TNC on stromal formation, we examined phenotypic changes in human mammary fibroblasts treated with TNC. The addition of TNC significantly up-regulated α-smooth muscle actin (α-SMA) and calponin. TNC increased the number of α-SMA- and/or calponin-positive cells with well-developed stress fibers in immunofluorescence, which enhanced contractile ability in collagen gel contraction. The treatment with TNC also significantly up-regulated its own synthesis. Double immunofluorescence of human breast cancer tissues showed α-SMA- and/or calponin-positive myofibroblasts in the TNC-deposited stroma. Among several receptors for TNC, the protein levels of the αv and β1 integrin subunits were significantly increased after the treatment. Immunofluorescence showed the augmented colocalization of αv and β1 at focal adhesions. Immunoprecipitation using an anti-αv antibody revealed a significant increase in coprecipitated β1 with TNC in lysates. The knockdown of αv and β1 suppressed the up-regulation of α-SMA and calponin. The addition of TNC induced the phosphorylation of SMAD2/3, whereas SB-505124 and SIS3 blocked myofibroblast differentiation. Therefore, TNC enhances its own synthesis by forming a positive feedback loop and increases integrin αvβ1 heterodimer levels to activate transforming growth factor-β signaling, which is followed by a change to highly contractile myofibroblasts. TNC may essentially contribute to the stiffer stromal formation characteristic of breast cancer tissues.

Tenascin-C accelerates adverse ventricular remodelling after myocardial infarction by modulating macrophage polarization

AIMS

Tenascin-C (TN-C) is an extracellular matrix protein undetected in the normal adult heart, but expressed in several heart diseases associated with inflammation. We previously reported that serum TN-C levels of myocardial infarction (MI) patients were elevated during the acute stage, and that patients with high peak TN-C levels were at high risk of left ventricular (LV) remodelling and poor outcome, suggesting that TN-C could play a significant role in the progression of ventricular remodelling. However, the detailed molecular mechanisms associated with this process remain unknown. We aimed to elucidate the role and underlying mechanisms associated with TN-C in adverse remodelling after MI.

METHODS AND RESULTS

MI was induced by permanent ligation of the coronary artery of TN-C knockout (TN-C-KO) and wild type (WT) mice. In WT mice, TN-C was expressed at the borders between intact and necrotic areas, with a peak at 3 days post-MI and observed in the immediate vicinity of infiltrating macrophages. TN-C-KO mice were protected from ventricular adverse remodelling as evidenced by a higher LV ejection fraction as compared with WT mice (19.0 ± 6.3% vs. 10.6 ± 4.4%; P < 0.001) at 3 months post-MI. During the acute phase, flow-cytometric analyses showed a decrease in F4/80+CD206lowCD45+ M1 macrophages and an increase in F4/80+CD206highCD45+ M2 macrophages in the TN-C-KO heart. To clarify the role of TN-C on macrophage polarization, we examined the direct effect of TN-C on bone marrow-derived macrophages in culture, observing that TN-C promoted macrophage shifting into an M1 phenotype via Toll-like receptor 4 (TLR4). Under M2-skewing conditions, TN-C suppressed the expression of interferon regulatory factor 4, a key transcription factor that controls M2-macrophage polarization, via TLR4, thereby inhibiting M2 polarization.

CONCLUSION

These results suggested that TN-C accelerates LV remodelling after MI, at least in part, by modulating M1/M2-macrophage polarization.

Tenascin-C promotes the repair of cartilage defects in mice

BACKGROUND

The effects of tenascin-C (TNC) on cartilage repair were examined in cartilage defect model mice. An in vitro study was also performed to determine the mechanism of cartilage repair with TNC.

METHODS

Full-thickness osteochondral defects were filled with TNC (group A: 100 μg/ml, group B: 10 μg/ml, group C: empty). Mice were sacrificed at 1, 2, 3, and 6 weeks postoperatively. Cartilage repair was histologically evaluated using the modified WAKITANI score. Chondrocytes were isolated and cultured, and they were treated with TNC. The expressions of various mRNAs including TNC, inflammatory cytokines, and anabolic and catabolic factors for cartilage were compared by real-time polymerase chain reaction.

RESULTS

The defects in group A were covered with hyaline-like cartilage after 3 weeks. Average modified WAKITANI scores were significantly better in group A than in groups B and C at 3 and 6 weeks. TNC upregulated the expressions of endogenous TNC, inflammatory cytokines, and anabolic and catabolic factors for cartilage. TNC downregulated the expression of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 5.

CONCLUSIONS

Intra-articular injection of full-length TNC repaired cartilage in murine models of full-thickness osteochondral defects. TNC upregulated the expression of ADAMTS4, but downregulated the expression of ADAMTS5 that contributed to cartilage degradation.

Evaluation of tenascin-C by tenatumomab in T-cell non-Hodgkin lymphomas identifies a new target for radioimmunotherapy

The clinical outcome of T-cell non-Hodgkin lymphoma (NHL) is poor and innovative treatments are needed. Tenascin-C is a large extracellular glycoprotein not expressed under physiological conditions, but overexpressed in cancer. Aim of the study was to evaluate tenascin-C expression within pathologic tissue of T-cell NHL and determine its clinical significance. We used an immunohistochemistry approach using the anti-tenascin-C monoclonal antibody Tenatumomab in 75 systemic T-cell NHL (including 72 mature and 3 precursor T-cell NHL), and 25 primary cutaneous T-cell NHL. Data were analyzed in terms of staining intensity, proportion of involved areas and histologic pattern, and results were correlated with clinical characteristics and outcome. Ninety-three percent of the cases were tenascin-C positive and 59% of systemic diseases were characterized by a predominant involvement (>50%). Stromal expression was detected in all the cases while vascular and vascular plus cytoplasmic expression was present in 49% and 23%. The constant overexpression of the tenascin-C gene was observed in two independent publicly available T-cell NHL gene expression datasets. In conclusions, tenascin-C represents an attractive target that sets the rationale to investigate the therapeutic activity of radiolabeled Tenatumomab in T-cell NHL.

Tenascin-C Prevents Articular Cartilage Degeneration in Murine Osteoarthritis Models

Objective The objective of this study was to determine whether intra-articular injections of tenascin-C (TNC) could prevent cartilage damage in murine models of osteoarthritis (OA). Design Fluorescently labeled TNC was injected into knee joints and its distribution was examined at 1 day, 4 days, 1 week, 2 weeks, and 4 weeks postinjection. To investigate the effects of TNC on cartilage degeneration after surgery to knee joints, articular spaces were filled with 100 μg/mL (group I), 10 μg/mL (group II) of TNC solution, or control (group III). TNC solution of 10 μg/mL was additionally injected twice after 3 weeks (group IV) or weekly after 1 week, 2 weeks, and 3 weeks (group V). Joint tissues were histologically assessed using the Mankin score and the modified Chambers system at 2 to 8 weeks after surgery. Results Exogenous TNC was maintained in the cartilage and synovium for 1 week after administration. Histological scores in groups I and II were better than scores in group III at 4 and 6 weeks, but progressive cartilage damage was seen in all groups 8 weeks postoperatively. Sequential TNC injections (groups IV and V) showed significantly better Mankin score than single injection (group II) at 8 weeks. Conclusion TNC administered exogenously remained in the cartilage of knee joints for 1 week, and could decelerate articular cartilage degeneration in murine models of OA. We also showed that sequential administration of TNC was more effective than a single injection. TNC could be an important molecule for prevention of articular cartilage damage.

Tenascin-C and integrins in cancer

Tenascin-C (TNC) is highly expressed in cancer tissues. Its cellular sources are cancer and stromal cells, including fibroblasts/myofibroblasts, and also vascular cells. TNC expressed in cancer tissues dominantly contains large splice variants. Deposition of the stroma promotes the epithelial-mesenchymal transition, proliferation, and migration of cancer cells. It also facilitates the formation of cancer stroma including desmoplasia and angiogenesis. Integrin receptors that mediate the signals of TNC have also been discussed.

Tenascin C in metastasis: A view from the invasive front

The extracellular matrix protein tenascin C (TNC) is a large glycoprotein expressed in connective tissues and stem cell niches. TNC over-expression is repeatedly observed in cancer, often at the invasive tumor front, and is associated with poor clinical outcome in several malignancies. The link between TNC expression and poor survival in cancer patients suggests a role for TNC in metastatic progression, which is responsible for the majority of cancer related deaths. Indeed, functional studies using mouse models are revealing new roles of TNC in cancer progression and underscore its important contribution to the development of metastasis. TNC has a pleiotropic role in advancing metastasis by promoting migratory and invasive cell behavior, angiogenesis and cancer cell viability under stress. TNC is an essential component of the metastatic niche and modulates stem cell signaling within the niche. This may be crucial for the fitness of disseminated cancer cells confronted with a foreign environment in secondary organs, that can exert a strong selective pressure on invading cells. TNC is a compelling example of how an extracellular matrix protein can provide a molecular context that is imperative to cancer cell fitness in metastasis.

Deficiency of tenascin-C and attenuation of blood-brain barrier disruption following experimental subarachnoid hemorrhage in mice

OBJECT Tenascin-C (TNC), a matricellular protein, is induced in the brain following subarachnoid hemorrhage (SAH). The authors investigated if TNC causes brain edema and blood-brain barrier (BBB) disruption following experimental SAH. METHODS C57BL/6 wild-type (WT) or TNC knockout (TNKO) mice were subjected to SAH by endovascular puncture. Ninety-seven mice were randomly allocated to WT sham-operated (n = 16), TNKO sham-operated (n = 16), WT SAH (n = 34), and TNKO SAH (n = 31) groups. Mice were examined by means of neuroscore and brain water content 24-48 hours post-SAH; and Evans blue dye extravasation and Western blotting of TNC, matrix metalloproteinase (MMP)-9, and zona occludens (ZO)-1 at 24 hours post-SAH. As a separate study, 16 mice were randomized to WT sham-operated, TNKO sham-operated, WT SAH, and TNKO SAH groups (n = 4 in each group), and activation of mitogen-activated protein kinases (MAPKs) was immunohistochemically evaluated at 24 hours post-SAH. Moreover, 40 TNKO mice randomly received an intracerebroventricular injection of TNC or phosphate-buffered saline, and effects of exogenous TNC on brain edema and BBB disruption following SAH were studied. RESULTS Deficiency of endogenous TNC prevented neurological impairments, brain edema formation, and BBB disruption following SAH; it was also associated with the inhibition of both MMP-9 induction and ZO-1 degradation. Endogenous TNC deficiency also inhibited post-SAH MAPK activation in brain capillary endothelial cells. Exogenous TNC treatment abolished the neuroprotective effects shown in TNKO mice with SAH. CONCLUSIONS Tenascin-C may be an important mediator in the development of brain edema and BBB disruption following SAH, mechanisms for which may involve MAPK-mediated MMP-9 induction and ZO-1 degradation. TNC could be a molecular target against which to develop new therapies for SAH-induced brain injuries.

Immunohistochemical localization of tenascin-C in rat periodontal ligament with reference to alveolar bone remodeling

We investigated the immunohistochemical localization of tenascin-C in 8-week-old rat periodontal ligaments. Tenascin-C immunoreactivity was detected in zones along with cementum and alveolar bone, and more intensely on the resorption surface of alveolar bone than on the formation surface. On the resorbing surface, tenascin-C immunoreactivity was detected in Howship's lacunae without osteoclasts, and in the interfibrous space of the periodontal ligaments, indicating that this molecule works as an adhesion molecule between bone and fibers of periodontal ligaments. Upon experimental tooth movement by inserting elastic bands (Waldo method), the physiological resorption surface of alveolar bone under compressive force showed enhanced bone resorption and enhanced tenascin-C immunoreactivity. However, on the physiological bone formation surface under compressive force, bone resorption was seen only occasionally, and no enhanced tenascin-C immunoreactivity was noted. In an experiment involving excessive occlusal loading to rat molars, transient bone resorption occurred within interradicular septa, but no enhanced tenascin-C immunoreactivity was seen in the periodontal ligaments. These results indicate that tenascin-C works effectively on the bone resorbing surface of physiological alveolar bone remodeling sites, rather than on the non-physiological transient bone resorbing surface. Fibronectin immunoreactivity was distributed evenly in the periodontal ligaments under experimental conditions. Co-localization of tenascin-C and fibronectin immunoreactivity was observed in many regions, but mutually exclusive expression patterns were also seen in some regions, indicating that fibronectin might not be directly involved in alveolar bone remodeling, but may play a role via interaction with tenascin-C.

Effect of tenascin-C on the repair of full-thickness osteochondral defects of articular cartilage in rabbits

The purpose of this study was to examine the effect of tenascin-C (TNC) on the repair of full-thickness osteochondral defects of articular cartilage in vivo. We used a gellan-gellan-sulfate sponge (Gellan-GS) to maintain a TNC-rich environment in the cartilage defects. We implanted Gellan-GS soaked in PBS only (Group 1), Gellan-GS soaked in 10 µg/ml of TNC (Group 2), and Gellan-GS soaked in 100 µg/ml of TNC (Group 3) into a full-thickness osteochondral defect of the patellar groove of rabbits. The defect area was examined grossly and histologically 4-12 weeks after surgery. Sections of synovium were also immunohistochemically investigated. Histologically as well as macroscopically, the defects in Group 2 showed better repair than the other groups at 8 and 12 weeks after surgery. Inflammation of the synovium tended to diminish over time in all groups, and the degree of synovitis was the same for all three groups at each time point. In conclusion, Gellan-GS soaked in TNC can be used as a novel scaffold for the repair of articular cartilage defects. This study also indicates that TNC promotes the repair of full-thickness osteochondral defects in vivo.

Tenascin-C and integrins in cancer

Tenascin-C (TNC) is highly expressed in cancer tissues. Its cellular sources are cancer and stromal cells, including fibroblasts/myofibroblasts, and also vascular cells. TNC expressed in cancer tissues dominantly contains large splice variants. Deposition of the stroma promotes the epithelial-mesenchymal transition, proliferation, and migration of cancer cells. It also facilitates the formation of cancer stroma including desmoplasia and angiogenesis. Integrin receptors that mediate the signals of TNC have also been discussed.

Vasoconstrictive effect of tenascin-C on cerebral arteries in rats

BACKGROUND AND PURPOSE

The authors have reported that tenascin-C (TNC), a matricellular protein, is induced after subarachnoid hemorrhage (SAH), associated with cerebral vasospasm. In this study, we examined whether TNC alone causes cerebral vasospasm-like constriction of the intracranial internal carotid arteries (ICAs) in rats, focusing on the p38 mitogen-activated protein kinase (MAPK)-mediated mechanisms.

METHODS

First, we injected 10 μg of TNC into the cisterna magna of healthy rats and studied morphologically whether TNC caused constriction of the left ICA at 24-72 h after administration. Second, we examined the effect of SB203580 (a p38 MAPK inhibitor) on the vessel diameter of the left ICA in healthy rats at 24 h. Third, we evaluated the effect of SB203580 on TNC-induced constriction of the left ICA in healthy rats at 24 h.

RESULTS

TNC significantly induced cerebral vasospasm-like angiographic constriction of the left ICAs, which continued at least for 72 h. SB203580 itself had no effect on the diameter of normal ICAs, but abolished the TNC-induced vasoconstrictive effect on the left ICA.

CONCLUSION

These findings show that TNC causes left ICA constriction via activation of p38 MAPK, resembling post-SAH vasospasm, and suggest the possible involvement of TNC in the pathogenesis of cerebral vasospasm.

Gellan sulfate core platinum coil with tenascin-C promotes intra-aneurysmal organization in rats

The aims of this study were to develop a new coil, gellan sulfate core platinum coil (GSCC), that delivers tenascin-C (TNC) to an aneurysm (GSCC-TNC) and to evaluate the effects on intra-aneurysmal organization. We performed in vitro adsorption tests of TNC to gellan sulfate (GS). GSCC-TNC was produced by immersing GSCC in TNC solution under the following conditions (TNC concentration 10, 50, or 100 μg/mL; TNC immersion time 15, 30, or 60 min) by monitoring intra-aneurysmal organization in a rat blind-ended aneurysm model. In addition, 20 rats randomly underwent implantation of a platinum coil or the GSCC-TNC produced under optimum conditions into an aneurysm, whose organization effects were compared in a blind fashion at 2 weeks post-surgery. GS demonstrated a high affinity to TNC in a dose-dependent fashion (affinity constant = 1.79 × 10(10) (M(-1))). GSCC immersed in 10 μg/mL of TNC solution for 30 and 60 min induced similar and better organization of aneurysmal cavity compared with that for 15 min (the ratio of the organized areas in an aneurysmal cavity-15 min, 27.2 ± 11.8 %; 30 min, 75.6 ± 11.9 %; 60 min, 82.6 ± 19.7 %, respectively) with the preservation of the aneurysmal wall structure, while higher TNC concentrations caused the destruction of the aneurysmal wall. GSCC-TNC produced under 10 μg/mL of TNC solution for 30 min showed a significantly better organization of aneurysms compared with bare platinum coils in rats. A newly developed coil, GSCC-TNC, may be effective for improving intra-aneurysmal organization after coil embolization.

Binding of αvβ1 and αvβ6 integrins to tenascin-C induces epithelial-mesenchymal transition-like change of breast cancer cells

Tenascin-C (TNC), a large hexameric extracellular glycoprotein, is a pleiotropic molecule with multiple domains binding to a variety of receptors mediating a wide range of cellular functions. We earlier reported that TNC induces epithelial–mesenchymal transition (EMT)-like change in breast cancer cells. In the present study, we clarified TNC receptor involvement in this process. Among integrins previously reported as TNC receptors, substantial expression of αv, α2, β1 and β6 subunits was detected by quantitative PCR and immunoblotting in MCF-7 cells. Integrin β6 mRNA was remarkably upregulated by transforming growth factor (TGF)-β1 treatment, and protein expression was prominently increased by additional exposure to TNC. Immunofluorescent labeling demonstrated integrin αvβ6 accumulation in focal adhesions after TNC treatment, especially in combination with TGF-β1. The α2 and β1 subunits were mainly localized at cell–cell contacts, αv being found near cell cluster surfaces. Immunoprecipitation showed increase in αvβ1 heterodimers, but not α2β1, after TNC treatment. Activated β1 subunits detected by an antibody against the Ca²⁺-dependent epitope colocalized with αv in focal adhesion complexes, associated with FAK phosphorylation at tyrosine 925. Neutralizing antibodies against αv and β1 blocked EMT-like change caused by TNC alone. In addition, anti-αv and combined treatment with anti-β1 and anti-αvβ6 inhibited TGF-β1/TNC-induced EMT, whereas either of these alone did not. Integrin subunits αv, β1 and β6, but not α2, bound to TNC immobilized on agarose beads in a divalent cation-dependent manner. Treatments with neutralizing antibodies against β1 and αvβ6 reduced αv subunit bound to the beads. Immunohistochemistry of these receptors in human breast cancer tissues demonstrated frequent expression of β6 subunits in cancer cells forming scattered nests localized in TNC-rich stroma. These findings provide direct evidence that binding of αvβ6 and αvβ1 integrins to TNC as their essential ligand induces EMT-like change in breast cancer cells.

Innovative strategy for microRNA delivery in human mesenchymal stem cells via magnetic nanoparticles

Bone marrow derived human mesenchymal stem cells (hMSCs) show promising potential in regeneration of defective tissue. Recently, gene silencing strategies using microRNAs (miR) emerged with the aim to expand the therapeutic potential of hMSCs. However, researchers are still searching for effective miR delivery methods for clinical applications. Therefore, we aimed to develop a technique to efficiently deliver miR into hMSCs with the help of a magnetic non-viral vector based on cationic polymer polyethylenimine (PEI) bound to iron oxide magnetic nanoparticles (MNP). We tested different magnetic complex compositions and determined uptake efficiency and cytotoxicity by flow cytometry. Additionally, we monitored the release, processing and functionality of delivered miR-335 with confocal laser scanning microscopy, real-time PCR and live cell imaging, respectively. On this basis, we established parameters for construction of magnetic non-viral vectors with optimized uptake efficiency (~75%) and moderate cytotoxicity in hMSCs. Furthermore, we observed a better transfection performance of magnetic complexes compared to PEI complexes 72 h after transfection. We conclude that MNP-mediated transfection provides a long term effect beneficial for successful genetic modification of stem cells. Hence, our findings may become of great importance for future in vivo applications.

Tenascin-C levels in synovial fluid are elevated after injury to the human and canine joint and correlate with markers of inflammation and matrix degradation

OBJECTIVE

We have previously shown the capacity of tenascin-C (TN-C) to induce inflammatory mediators and matrix degradation in vitro in human articular cartilage. The objective of the present study was to follow TN-C release into knee synovial fluid after acute joint injury or in joint disease, and to correlate TN-C levels with markers of cartilage matrix degradation and inflammation.

METHOD

Human knee synovial fluid samples (n = 164) were from a cross-sectional convenience cohort. Diagnostic groups were knee healthy reference, knee anterior cruciate ligament rupture, with or without concomitant meniscus lesions, isolated knee meniscus injury, acute inflammatory arthritis (AIA) and knee osteoarthritis (OA). TN-C was measured in synovial fluid samples using an enzyme-linked immunosorbent assay (ELISA) and results correlated to other cartilage markers. TN-C release was also monitored in joints of dogs that underwent knee instability surgery.

RESULTS

Statistically significantly higher levels of TN-C compared to reference subjects were observed in the joint fluid of all human disease groups and in the dogs that underwent knee instability surgery. Statistically significant correlations were observed between the TN-C levels in the synovial fluid of the human patients and the levels of aggrecanase-dependent Ala-Arg-Gly-aggrecan (ARG-aggrecan) fragments and matrix metalloproteinases 1 and 3.

CONCLUSIONS

We find highly elevated levels of TN-C in human knee joints after injury, AIA or OA that correlated with markers of cartilage degradation and inflammation. TN-C in synovial fluid may serve dual roles as a marker of joint damage and a stimulant of further joint degradation.

β3GnT8 regulates laryngeal carcinoma cell proliferation via targeting MMPs/TIMPs and TGF-β1

Previous evidence showed β1, 3-N-acetylglucosaminyltransferase 8 (β3GnT8), which can extend polylactosamine on N-glycans, to be highly expressed in some cancer cell lines and tissues, indicating roles in tumorigenesis. However, so far, the function of β3GnT8 in laryngeal carcinoma has not been characterized. To test any contribution, Hep-2 cells were stably transfected with sense or interference vectors to establish cell lines that overexpressed or were deficient in β3GnT8. Here we showed that cell proliferation was increased in β3GnT8 overexpressed cells but decreased in β3GnT8 knockdown cells using MTT. Furthermore, we demonstrated that change in β3GnT8 expression had significant effects on tumor growth in nude mice.We further provided data suggesting that overexpression of β3GnT8 enhanced the expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) at both the mRNA and protein levels, associated with shedding of tissue inhibitors of metalloproteinase TIMP-2. In addition, it caused increased production of transforming growth factor beta 1 (TGF-β1), whereas β3GnT8 gene knockdown caused the reverse effect. The results may indicate a novel mechanism by which effects of β3GnT8 in regulating cellular proliferation are mediated, at least in partvia targeting MMPs/TIMPs and TGF-β1 in laryngeal carcinoma Hep-2 cells. The finding may lay a foundation for further investigations into the β3GnT8 as a potential target for therapy of laryngeal carcinoma.

Tenascin-C induces prolonged constriction of cerebral arteries in rats

Tenascin-C (TNC), a matricellular protein, is induced in association with cerebral vasospasm after subarachnoid hemorrhage. The aim of this study was to assess the vasoconstrictive effects of TNC and its mechanisms of action on cerebral arteries in vivo. Two dosages (1 and 10μg) of TNC were administered intracisternally to healthy rats, and the effects were evaluated by neurobehavioral tests and India-ink angiography at 24, 48, and 72h after the administration. Western blotting and immunohistochemistry were performed to explore the underlying mechanisms on constricted cerebral arteries after 24h. The effects of toll-like receptor 4 (TLR4) antagonists (LPS-RS), c-Jun N-terminal kinase (JNK), and p38 inhibitors (SP600125 and SB203580) on TNC-induced vasoconstriction were evaluated at 24h. Higher dosages of TNC induced more severe cerebral arterial constriction, which continued for more than 72h. TNC administration also upregulated TLR4, and activated JNK and p38 in the smooth muscle cell layer of the constricted cerebral artery. LPS-RS blocked TNC-induced TLR4 upregulation, JNK and p38 activation, and vasoconstrictive effects. SP600125 and SB203580 abolished TNC-induced TLR4 upregulation and vasoconstrictive effects. TNC may cause prolonged cerebral arterial constriction via TLR4 and activation of JNK and p38, which may upregulate TLR4. These findings suggest that TNC causes cerebral vasospasm and provides a novel therapeutic approach against it.

Extracellular matrix protein tenascin-C is required in the bone marrow microenvironment primed for hematopoietic regeneration

The BM microenvironment is required for the maintenance, proliferation, and mobilization of hematopoietic stem and progenitor cells (HSPCs), both during steady-state conditions and hematopoietic recovery after myeloablation. The ECM meshwork has long been recognized as a major anatomical component of the BM microenvironment; however, the molecular signatures and functions of the ECM to support HSPCs are poorly understood. Of the many ECM proteins, the expression of tenascin-C (TN-C) was found to be dramatically up-regulated during hematopoietic recovery after myeloablation. The TN-C gene was predominantly expressed in stromal cells and endothelial cells, known as BM niche cells, supporting the function of HSPCs. Mice lacking TN-C (TN-C(-/-)) mice showed normal steady-state hematopoiesis; however, they failed to reconstitute hematopoiesis after BM ablation and showed high lethality. The capacity to support transplanted wild-type hematopoietic cells to regenerate hematopoiesis was reduced in TN-C(-/-) recipient mice. In vitro culture on a TN-C substratum promoted the proliferation of HSPCs in an integrin α9-dependent manner and up-regulated the expression of the cyclins (cyclinD1 and cyclinE1) and down-regulated the expression of the cyclin-dependent kinase inhibitors (p57(Kip2), p21(Cip1), p16(Ink4a)). These results identify TN-C as a critical component of the BM microenvironment that is required for hematopoietic regeneration.

Tenascin-C enhances crosstalk signaling of integrin αvβ3/PDGFR-β complex by SRC recruitment promoting PDGF-induced proliferation and migration in smooth muscle cells

Migration and proliferation of smooth muscle cells (SMCs) are key events during neointimal formation in pathological conditions of vessels. Tenascin-C (TNC) is upregulated in the developing neointima of lesions. We evaluated the effects of TNC on responses of SMCs against platelet-derived growth factor (PDGF) stimulation. TNC coated on substrate promoted PDGF-BB-induced proliferation and migration of rat SMC cell line A10 in BrdU incorporation and transwell assays, respectively. Immunoblotting showed that TNC substrate enhanced autophosphorylation of PDGFR-β after PDGF-BB stimulation. Integrin αvβ3 is known to be a receptor for TNC in SMCs. In immunofluorescence and immunoblot of integrin αv subunit, clustering of αv-positive focal adhesions and upregulated αv expression were observed in the cells on TNC substrate. Immunoprecipitation using anti-integrin αvβ3 antibody demonstrated that PDGFR-β and integrin αvβ3 were co-precipitated and that the relative amount of PDGFR-β after the stimulation was increased by TNC treatment. TNC also promoted phosphorylation of focal adhesion kinase (FAK) at tyrosine (Y) 397 and Y925. The phosphorylated FAK was localized at focal adhesions in immunofluorescence. Phosphorylated SRC at Y418 was also seen at focal adhesions. Immunoprecipitation with αv antibody showed increased SRC association with the integrin signaling complex in the cells on TNC after PDGF treatment. In the cells on TNC substrate, crosstalk signaling between integrin αvβ3 and PDGFR-β could be amplified by SRC and FAK recruited to focal adhesions, followed by enhanced proliferation and migration of A10 cells by PDGF-BB.

Tenascin-C induces inflammatory mediators and matrix degradation in osteoarthritic cartilage

Background

Tenascin-C (TN-C) is an extracellular matrix glycoprotein that is involved in tissue injury and repair processes. We analyzed TN-C expression in normal and osteoarthritic (OA) human cartilage, and evaluated its capacity to induce inflammatory and catabolic mediators in chondrocytes in vitro. The effect of TN-C on proteoglycan loss from articular cartilage in culture was also assessed.

Methods

TN-C in culture media, cartilage extracts, and synovial fluid of human and animal joints was quantified using a sandwich ELISA and/or analyzed by Western immunoblotting. mRNA expression of TN-C and aggrecanases were analyzed by Taqman assays. Human and bovine primary chondrocytes and/or explant culture systems were utilized to study TN-C induced inflammatory or catabolic mediators and proteoglycan loss. Total proteoglycan and aggrecanase -generated ARG-aggrecan fragments were quantified in human and rat synovial fluids by ELISA.

Results

TN-C protein and mRNA expression were significantly upregulated in OA cartilage with a concomitant elevation of TN-C levels in the synovial fluid of OA patients. IL-1 enhanced TN-C expression in articular cartilage. Addition of TN-C induced IL-6, PGE₂, and nitrate release and upregulated ADAMTS4 mRNA in cultured primary human and bovine chondrocytes. TN-C treatment resulted in an increased loss of proteoglycan from cartilage explants in culture. A correlation was observed between TN-C and aggrecanase generated ARG-aggrecan fragment levels in the synovial fluid of human OA joints and in the lavage of rat joints that underwent surgical induction of OA.

Conclusions

TN-C expression in the knee cartilage and TN-C levels measured in the synovial fluid are significantly enhanced in OA patients. Our findings suggest that the elevated levels of TN-C could induce inflammatory mediators and promote matrix degradation in OA joints.

Tenascin C induces epithelial-mesenchymal transition-like change accompanied by SRC activation and focal adhesion kinase phosphorylation in human breast cancer cells

Tenascin C (TNC) is an extracellular matrix glycoprotein up-regulated in solid tumors. Higher TNC expression is shown in invading fronts of breast cancer, which correlates with poorer patient outcome. We examined whether TNC induces epithelial-mesenchymal transition (EMT) in breast cancer. Immunohistochemical analysis of invasive ductal carcinomas showed that TNC deposition was frequent in stroma with scattered cancer cells in peripheral margins of tumors. The addition of TNC to the medium of the MCF-7 breast cancer cells caused EMT-like change and delocalization of E-cadherin and β-catenin from cell-cell contact. Although amounts of E-cadherin and β-catenin were not changed after EMT in total lysates, they were increased in the Triton X-100-soluble fractions, indicating movement from the membrane into the cytosol. In wound healing assay, cells were scattered from wound edges and showed faster migration after TNC treatment. The EMT phenotype was correlated with SRC activation through phosphorylation at Y418 and phosphorylation of focal adhesion kinase (FAK) at Y861 and Y925 of SRC substrate sites. These phosphorylated proteins colocalized with αv integrin-positive adhesion plaques. A neutralizing antibody against αv or a SRC kinase inhibitor blocked EMT. TNC could induce EMT-like change showing loss of intercellular adhesion and enhanced migration in breast cancer cells, associated with FAK phosphorylation by SRC; this may be responsible for the observed promotion of TNC in breast cancer invasion.

Distribution and role of tenascin-C in human osteoarthritic cartilage

BACKGROUND

Tenascin-C (TN-C) is expressed in the cartilage of osteoarthritis (OA). We examined whether TN-C was involved in cartilage repair of the diseased joints. Human articular cartilage samples were obtained from patients with OA and those with normal joints.

METHODS

Immunohistochemistry testing of TN-C, chondroitin sulfate (CS), and proliferating cell nuclear antigen (PCNA) was performed. Chondrocytes were isolated from human cartilage and cultured. After treatment with TN-C, chondrocyte proliferation s was analyzed by bromodeoxyuridine (BrdU) incorporation assay using an enzyme-linked immunosorbent assay kit. Glycosaminoglycan content was determined by dimethylmethylene blue (DMMB) assay. The mRNA expression of aggrecan was also analyzed, by quantitative real-time polymerase chain reaction (PCR).

RESULTS

In osteoarthritic cartilage, increased TN-C staining was observed with the degeneration of articular cartilage in comparison with normal cartilage. TN-C staining was shown in the cartilage surface overlying CS-positive areas. In addition, the expression of PCNA in the positive areas for TN-C was significantly higher than that in the negative areas. Treatment of human articular chondrocytes with 10 μg/ml TN-C accelerated chondrocyte proliferation, increased the proteoglycan amount in culture, and increased the expression of aggrecan mRNA.

CONCLUSIONS

Our findings indicate that the distribution of TN-C is related to CS production and chondrocyte proliferation in osteoarthritic cartilage and that TN-C has effects on DNA synthesis, proteoglycan content, and aggrecan mRNA expression in vitro. TN-C may be responsible for repair in human osteoarthritic cartilage.

Deficiency of tenascin-C delays articular cartilage repair in mice

OBJECTIVE

In human articular cartilage, tenascin-C (TN-C) expression decreases during maturation of chondrocytes, and almost disappears in adults; however, it reappears in damaged cartilage. To examine the effects of TN-C on cartilage degeneration and repair, we compared articular cartilage degeneration between wild-type (WT) and tenascin-C knockout mouse (TNKO) mice using a spontaneous osteoarthritis (OA) in aged joints and surgical OA model. In addition, we made full-thickness cartilage defects and compared the cartilage repair process between the two groups.

METHODS

The surgical procedure to create degenerative OA model was performed by transecting the anterior cruciate ligament and medial collateral ligament. Full-thickness defects were created in the center of the femoral trochlea to evaluate cartilage repair. Sections of cartilage were stained with hematoxylin and eosin or safranin-O, and immunostaining for TN-C. The degrees of degeneration and repair were graded.

RESULTS

In the WT surgical OA model, the articular cartilage was almost normal at 2 weeks, but safranin-O decreased staining at 4 weeks. In TNKO mice, safranin-O decreased staining at 2 weeks, and cartilage was injured intensely at 4 weeks. In the cartilage repair model, TN-C was expressed after 1 week, was strongly expressed in the upper layer of regenerated tissue after 3 weeks, and disappeared after 6 weeks. The defects were restored until 6 weeks in WT mice; however, defects in TNKO mice were filled with fibrous tissue with no cartilage-like tissue.

CONCLUSIONS

This study revealed that cartilage repair in TNKO mice was significantly slower than that in WT mice and that the deficiency of TN-C progressed during cartilage degeneration.

Tumour-associated tenascin-C isoforms promote breast cancer cell invasion and growth by matrix metalloproteinase-dependent and independent mechanisms

INTRODUCTION

The stromal microenvironment has a profound influence on tumour cell behaviour. In tumours, the extracellular matrix (ECM) composition differs from normal tissue and allows novel interactions to influence tumour cell function. The ECM protein tenascin-C (TNC) is frequently up-regulated in breast cancer and we have previously identified two novel isoforms - one containing exon 16 (TNC-16) and one containing exons 14 plus 16 (TNC-14/16).

METHODS

The present study has analysed the functional significance of this altered TNC isoform profile in breast cancer. TNC-16 and TNC-14/16 splice variants were generated using PCR-ligation and over-expressed in breast cancer cells (MCF-7, T47D, MDA-MD-231, MDA-MB-468, GI101) and human fibroblasts. The effects of these variants on tumour cell invasion and proliferation were measured and compared with the effects of the large (TNC-L) and fully spliced small (TNC-S) isoforms.

RESULTS

TNC-16 and TNC-14/16 significantly enhanced tumour cell proliferation (P < 0.05) and invasion, both directly (P < 0.01) and as a response to transfected fibroblast expression (P < 0.05) with this effect being dependent on tumour cell interaction with TNC, because TNC-blocking antibodies abrogated these responses. An analysis of 19 matrix metalloproteinases (MMPs) and tissue inhibitor of matrix metalloproteinases 1 to 4 (TIMP 1 to 4) revealed that TNC up-regulated expression of MMP-13 and TIMP-3 two to four fold relative to vector, and invasion was reduced in the presence of MMP inhibitor GM6001. However, this effect was not isoform-specific but was elicited equally by all TNC isoforms.

CONCLUSIONS

These results demonstrate a dual requirement for TNC and MMP in enhancing breast cancer cell invasion, and identify a significant role for the tumour-associated TNC-16 and TNC-14/16 in promoting tumour invasion, although these isoform-specific effects appear to be mediated through MMP-independent mechanisms.

Injectable iron-modified apatitic bone cement intended for kyphoplasty: cytocompatibility study

In this study, the cytocompatibility of human ephitelial (HEp-2) cells cultured on new injectable iron-modified calcium phosphate cements (IM-CPCs) has been investigated in terms of cell adhesion, cell proliferation, and morphology. Quantitative MTT-assay and scanning electron microscopy (SEM) showed that cell adhesion and viability were not affected with culturing time by iron concentration in a dose-dependent manner. SEM-cell morphology showed that HEp-2 cells, seeded on IM-CPCs, were able to adhere, spread, and attain normal morphology. These results showed that the new injectable IM-CPCs have cytocompatible features of interest to the intended kyphophasty application, for the treatment of osteoporotic vertebral compression fractures.

Clinical significance of large tenascin-C spliced variant as a potential biomarker for colorectal cancer

BACKGROUND

Tenascin-C is an extracellular matrix protein forming various types of spliced variants. Low molecule variants are transiently present, but large spliced variants are predominantly overexpressed in proliferative processes or tumorigenesis in some varieties of cancer. However, the detection of the plasma level of large tenascin-C spliced variant (L-Tn-CSV) in colorectal cancer (CRC) has not been clarified. This study was performed to validate elevated plasma L-Tn-CSV levels as a possible biomarker for CRC.

MATERIALS AND METHODS

Plasma samples were obtained before resection and from time to time postoperatively and stored at -80 degrees C until assay. Plasma L-Tn-CSV levels were evaluated in patients with primary (n = 162) and with recurrent (n = 20) CRC, including 48 healthy volunteers, measured by ELISA.

RESULTS

The average plasma L-Tn-CSV concentrations of patients with primary CRC were 5,260 +/- 3,243.3 pg/ml and of patients with recurrent CRC 4,106 +/- 2,261.1 pg/ml, which were significantly elevated in comparison with those of healthy volunteers (2,364.3 +/- 7,49.6). The sensitivity for detecting CRC using plasma L-Tn-CSV was 56.6%, based on the mean +/- 2 SD of the concentrations of healthy controls (3,863.5), which was significantly higher than CEA (40.1%) and CA19-9 (23.6%). No obvious associations were evident between plasma L-Tn-CSV status and values of CEA and CA19-9 respectively. Statistically significant differences in plasma L-Tn-CSV were observed depending on tumor depth, lymph node metastasis, and TNM stage. Negative conversions of plasma L-Tn-CSV levels 6 months after resection were significantly higher in the completely curative resection group than in the non-curative groups (P < 0.001).

CONCLUSION

The plasma L-Tn-CSV may serve very well as a useful biomarker for tumor staging and postoperative monitoring of preoperatively positive CRC that is independent and exceeds conventional tumor markers.

Tenascin-C induced signaling in cancer

Tenascin-C is an adhesion modulatory extracellular matrix molecule that is highly expressed in the microenvironment of most solid tumors. High tenascin-C expression reduces the prognosis of disease-free survival in patients with some cancers. The possible role of tenascin-C in tumor initiation and progression is addressed with emphasis on underlying signaling mechanisms. How tenascin-C affects malignant transformation, uncontrolled proliferation, angiogenesis, metastasis and escape from tumor immunosurveillance is summarized. Finally, we discuss how the phenotypes of tenascin-C knock-out mice may help define the roles of tenascin-C in tumorigenesis and how this knowledge could be applied to cancer therapy.

Distribution pattern of Tenascin-C in glioblastoma: Correlation with angiogenesis and tumor cell proliferation

Tenascin-C (TN-C) is an extracellular matrix protein which participates in different processes like normal fetal development, wound healing, inflammation, keloids and rheumatoid arthritis. Furthermore, the immunostaining for TN-C is seen in the stroma of various malignant tumors as in glioblastoma multiforme (GBM), however, the significance of these findings is still not clear. In this study 62 GBM samples were analyzed immunohistochemically for distribution patterns of TN-C and correlated with angiogenesis and tumor cell proliferation. Tenascin-C in GBM localizes in two compartments, perivascular and intercellular space. Intercellular tenascin-C (TN-C ic) showed focal distribution in 66%, and diffuse one in 34% of cases. Perivascular tenascin-C (TN-C pv) showed strong correlation with microvascular density (MVD) and vascular endothelial growth factor (VEGF) expression. Moreover, it seems that TN-C pv enhanced the effect of VEGF. Intercellular TN-C did not correlate with MVD and VEGF expression, but showed strong correlation with proliferation index. Furthermore, tumors with diffuse TN-C ic expression had higher proliferation indices than tumors with focal TN-C expression. Our results indicate that TN-C plays a role in angiogenesis and tumor cell proliferation, but beside the intensity of expression, the distribution patterns are also important in these processes. This study also suggests that perivascular and intercellular TN-C compartments have probably different sources and different roles in GBM.

Tenascin-C protein expression and mRNA splice variants in thyroid carcinoma

Tenascin-C (Tn-C) is a matricellular protein involved in the initial and intermediate stages of cell adhesion. The present study is the first undertaken to comparatively investigate Tn-C in neoplastic, non-neoplastic thyroid lesions and normal thyroid tissues. Forty-eight thyroid specimens were studied immunohistochemically using a monoclonal antibody against Tn-C. Immunohistochemistry was supplemented by RT-PCR analysis of the two Tn-C mRNA splice variants in 13 thyroid cancer cell lines. Normal and non-neoplastic tissues were devoid of Tn-C, as well as follicular neoplasms, Huerthle-cell and anaplastic carcinomas. Most papillary carcinomas showed a focally intensive extracellular staining, localized in the connective tissue stroma, whereas most medullary carcinomas showed a staining in the connective tissue but also in intracellular location mainly. RT-PCR analysis detected Tn-C mRNA in all thyroid cancer cell lines with prevalence of the large splice variant in all but the medullary line, characterized by a higher Tn-Csmall:Tn-Clarge ratio. In conclusion, Tn-C re-expression has been observed in papillary and medullary thyroid carcinomas with different staining patterns accompanied by the prevalence of different mRNA splice variants in cell cultures. It seems possible that Tn-C is rather synthesized by tumor cells than by activated stromal cells.

Expression of matrix metalloproteinase-3 in mouse endometrial stromal cells during early pregnancy: regulation by interleukin-1alpha and tenascin-C

During the peri-implantation period, the endometrium undergoes tissue remodeling and cellular rearrangement. To clarify the involvement of matrix metalloproteinases (MMPs) in endometrial remodeling, we isolated total RNAs from the endometrium of non-pregnant and pregnant mice on days 3 to 5 and evaluated mRNA expression of MMP-2, -3, -9, -11 and -13 using reverse transcription-polymerase chain reaction (PCR). Prompt increases in MMP-3 and -13 mRNA were found on day 4 of pregnancy. Quantitative real-time PCR showed that expression of MMP-3 and -13 increased significantly on day 4, up to 8.4 +/- 2.7 times and 3.4 +/- 1.5 times, respectively, the level in non-pregnant endometrium (p < 0.05). On day 4, immunohistochemistry demonstrated MMP-3-positive endometrial stromal cells. At the same time, tenascin-C (TN-C) mRNA increased 11.1 +/- 4.0 times from the level in non-pregnant endometrium (p < 0.004). To clarify regulation of MMP-3 expression, we examined the effects of interleukin-1alpha (IL-1alpha) and TN-C on MMP-3 mRNA in cultured mouse endometrial stromal cells. Both substances resulted in a dose-dependent increase in MMP-3 mRNA (6.1 +/- 1.8-fold at 1 ng/ml of IL-1alpha and 3.9 +/- 1.8-fold at 10 mug/ml of TN-C). This study shows that MMP-3 expression is upregulated in endometrial stromal cells of the peri-implantation period and may be controlled by IL-1alpha and TN-C.

Tenascin-C regulates proliferation and migration of cultured astrocytes in a scratch wound assay

Tenascin-C (TNC), an extracellular matrix glycoprotein, is involved in tissue morphogenesis like embryogenesis, wound healing or tumorigenesis. Astrocytes are known to play major roles in wound healing in the CNS. To elucidate the roles of TNC in wound closure by astrocytes, we have examined the morphological changes of cultured astrocytes in a scratch wound assay and measured the content of soluble TNC released into the medium. We have also localized the expression of TNC mRNA, TNC, glial fibrillary acidic protein (GFAP), vimentin and integrin beta1. After wounding, glial cells rapidly released the largest TNC isoform and proliferated in the border zones. Subsequently, they became polarized with unidirectional processes and finally migrated toward the denuded area. The proliferating border zone cells and pre-migratory cells intensely expressed TNC mRNA, TNC-, vimentin-, GFAP- and integrin beta1-like immunoreactivity, while the migratory cells showed generally reduced expression except the front. Exogenous TNC enhanced cell proliferation and migration, while functional blocking with anti-TNC or anti-integrin beta1 antibody reduced both of them. These results suggest that mechanical injury induces boundary astrocytes to produce and release TNC that promotes cell proliferation and migration via integrin beta1 in an autocrine/paracrine fashion.

Tenascin-C regulates recruitment of myofibroblasts during tissue repair after myocardial injury

Tenascin-C (TN-C) is an extracellular matrix molecule that is expressed during wound healing in various tissues. Although not detectable in the normal adult heart, it is expressed under pathological conditions. Previously, using a rat model, we found that TN-C was expressed during the acute stage after myocardial infarction and that alpha-smooth muscle actin (alpha-SMA)-positive myofibroblasts appeared in TN-C-positive areas. In the present study, we examined whether TN-C controls the dynamics of myofibroblast recruitment and wound healing after electrical injury to the myocardium of TN-C knockout (TNKO) mice compared with wild-type (WT) mice. In TNKO mice, myocardial repair seemed to proceed normally, but the appearance of myofibroblasts was delayed. With cultured cardiac fibroblasts, TN-C significantly accelerated cell migration, alpha-SMA expression, and collagen gel contraction but did not affect proliferation. Using recombinant fragments of murine TN-C, the functional domain responsible for promoting migration of cardiac fibroblasts was mapped to the conserved fibronectin type III (FNIII)-like repeats and the fibrinogen (Fbg)-like domain. Furthermore, alternatively spliced FNIII and Fbg-like domains proved responsible for the up-regulation of alpha-SMA expression. These results indicate that TN-C promotes recruitment of myofibroblasts in the early stages of myocardial repair by stimulating cell migration and differentiation.

O papel das proteínas da matriz extracelular e das metaloproteinases em carcinomas de cabeça e pescoço: uma atualização bibliográfica

Interações entre células neoplásicas e constituintes da matriz extracelular (MEC) interferem fortemente no desenvolvimento tumoral, incluindo os localizados em cabeça e pescoço, pois influenciam a proliferação e sobrevivência celular, bem como a sua capacidade de migrar do sítio primário para outros tecidos e formar metástases. Essa migração celular é facilitada pela destruição parcial da MEC, a qual é realizada pelas metaloproteinases (MMPs), que representam uma família de mais de vinte endopeptidases, com atividade controlada pela expressão de inibidores específicos (TIMPs). Diversos estudos utilizando-se de marcadores para constituintes da MEC bem como pelas MMPs têm fornecido informações adicionais sobre o diagnóstico e prognóstico em carcinomas de cabeça e pescoço. Nesta revisão consideraremos o papel da MEC e das MMPs na progressão desses tumores, enfatizando que não somente a degradação proteolítica está envolvida neste processo, como também interações entre vários constituintes da MEC fornecem substrato para regulação e crescimento destes tumores.

Co-stimulation of human breast cancer cells with transforming growth factor-beta and tenascin-C enhances matrix metalloproteinase-9 expression and cancer cell invasion

Transforming growth factor-beta (TGF-beta), tenascin-C (TN-C) and matrix metalloproteinases (MMPs) have been demonstrated independently to be associated with disease progression and poor prognosis in patients with breast cancer. The present study explored effects of TGF-beta and TN-C on MMP-9 expression and cancer invasion. An experimental study was designed to analyse MDA-MB-231 breast cancer cells, known for their high invasiveness, after stimulation with TGF-beta1 and/or TN-C. TGF-beta1 stimulated TN-C expression in the cells. Co-stimulation of MDA-MB-231 cells with TN-C and TGF-beta increased MMP-9 expression at both the gene (28-fold) and the protein levels. The in vitro invasion also increased (4-fold). GM6001 inhibited the invasion induced by the co-stimulation. The combined effect of TN-C and TGF-beta resulted in enhanced MMP-9 expression and cancer invasion in vitro.

The role of matrix extracellular proteins and metalloproteinases in head and neck carcinomas: an updated review

Interactions involving tumor cells and the extracellular matrix (ECM) strongly influence tumor development, including head and neck tumors, affecting cell proliferation and survival as well as the ability to migrate beyond the original location into other tissues to form metastases. These cell migration is often facilitated by partial destruction of the surrounding ECM, which is catalyzed by matrix metalloproteinases (MMPs), a family of more than 20 endopeptidases that is controlled by regulated expression of specific inhibitors (TIMPs). Several studies of ECM and MMPs markers have provided additional diagnostic and prognostic information in head and neck carcinomas. In this review, we are considering the role of ECM and MMPs in tumor progression, emphasizing its proteolytic contributors to this process, and interactions between several members of ECM providing substrate to regulation of this process.

Prognostic significance of matrix metalloproteinase-2, cathepsin D, and tenascin-C expression in colorectal carcinoma

Matrix metalloproteinase-2 (MMP-2) and cathepsin D (CD) play a significant role in degrading the components of basement membrane and extracellular matrix (ECM), whereas tenascin-C (TN-C) is a glycoprotein of the ECM related to cell adhesion and detachment. These proteins have been implicated in tumor invasion and metastasis. Therefore, we aimed at investigating the prognostic significance of MMP-2, CD, and TN-C expressions in primary colorectal cancer. Overall, 112 colorectal adenocarcinomas were included in the present study. MMP-2, CD, and TN-C expressions were evaluated by immunohistochemistry and correlated with clinicopathologic prognostic parameters and survival. Diffuse stromal TN-C immunostaining was found to be significantly correlated with advanced stage and shorter survival time (p = 0.002 and 0.02, respectively). MMP-2 expression was found to correlate with lymph vessel invasion (p = 0.006) and stage (p = 0.03). CD expression was related to depth of invasion (p = 0.005). No significant relationship was found between survival and MMP-2 and CD expression (p > 0.05). In multivariate analysis, stage and vascular invasion were independent prognostic factors, whereas TN-C did not retain a clear independent relationship to survival (p > 0.05). Our findings suggest that TN-C expression may be a potential prognostic marker in colorectal carcinoma. However, MMP-2 and CD do not appear to be significant indicators of survival.

Distribution of tenascin-C and -X and expression of tenascin-C and X mRNA in the postnatal rat tongue

Different distributions of tenascin-C and -X are found in various organs. However, the role of the tenascin family in the process of formation in the papillae epithelium during development is poorly understood. In order to find more information an tenascin-C and -X distributions during tongue development, immunohistocheminical studies have been carried out to demonstrate these distributions. The number of PCNA positive cells gradually increased from 5- to 15-days, and decreased on 21-days in the intercellular space of the epithelal layer in the postnatal development of rat tongue (150 specimens of Wistar male rats (0-, 5-, 10-, 15-, and 21-days). The reaction of tenascin-C was found mainly in the intercellular space of the epithelial layer on contrast to that of tenascin-X which was mainly found an the epithelial layer under a confocal laser scanning microscope. The level of mRNA of tenascin-C (600bp) and tenascin-X (588bp) gradually decreased from 5-days using RT-PCR methods. The different distribution of these extracellular matrices and weakly-regulated expressions may be related to the replication process of the epithelium in the tongue during development.

Distribution of tenascin-C and -X, and soft X-ray analysis of the mandibular symphysis during mandible formation in the human fetus

In the development of the human mandible, the process of bone calcification, distribution and expression of tenascin-C and -X in the mental symphyseal region are unknown. The purpose of this study was to determine the distribution of these extracellular matrices in the connective tissue around calcified tissues located on the mental symphyseal region of the human fetus during development through histological and radiographical studies. The radiographic density increased from 16 weeks to 24 weeks gestation in all examined regions; in contrast, the diameter of muscle fiber in the suprahyoid muscles (digastric anterior and geniohyoid muscles) inserted into the inner mental symphyseal region increased from 24 weeks gestation. The extracellular matrices (tenascin) were shown to have a different distribution in the mental symphyseal region of the human fetus at each stage. These different distributions of tenascin-C and -X were found around the epithelium and the endomysium of the mental symphyseal region, and affect the specific formation of the mandible during ossification with hyoid muscle development in human fetus.

Tenascin C and cathepsin d expression in adipocytic tumors: an immunohistochemical investigation of 43 cases

Cathepsin D (CatD) and tenascin C (Tn-C) have been implicated in invasion and metastasis of carcinomas. However, little is known about CatD and Tn-C distribution in mesenchymal tumors. Therefore, we aimed to investigate the expression of Tn-C and CatD in adipocytic tumors. Tn-C and CatD expressions in 27 lipomas, 5 atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDLS) and 11 liposarcomas (LS) were evaluated by immunohistochemistry and scored semiquantitatively. CatD expression was higher in ALT/WDLS than in lipomas (p<0.001), and higher in LS than in ALT/WDLS (p=0.009). Stromal Tn-C expression was higher in ALT/WDLS than in lipomas (p=0.02), but no difference was observed between ALT/WDLS and LS (p>0.05). These results indicate that Tn-C and CatD may be markers of locally aggressive or malignant behavior in adipocytic tumors.

Prognostic significance of tenascin-C expression in superficial and invasive bladder cancer

AIMS

Tenascin-C (Tn-C) is an extracellular matrix glycoprotein that is upregulated in malignant tumours. Tn-C promotes cell growth, cell migration, and angiogenesis. It has been suggested to be a prognostic factor in various types of malignant tumours, but there is little information on its significance in bladder cancer with regard to overall survival (OS) and recurrence free survival (RFS).

METHODS

Tn-C expression was studied in 106 patients with bladder cancer diagnosed between 1994 and 1997. Immunohistochemistry was performed using a monoclonal antibody against Tn-C. RFS and OS were estimated by the Kaplan-Meier method and compared by the log rank test in univariate analysis and by the Cox multistep regression method in multivariate analysis.

RESULTS

Within the mean follow up period of 126 months, patients with diffuse Tn-C staining in the tumour stroma had a significantly worse OS than those with negative staining or only moderate Tn-C expression (p = 0.025). Patients with cytoplasmic expression of Tn-C had a significantly better OS than those without (p = 0.001). Multivariate analysis, taking into consideration age, grade, stage, tumour associated carcinoma in situ, progression, and Tn-C staining in tumour stroma, showed that only expression of Tn-C in invasive tumour cells was an independent positive prognostic factor for OS (p = 0.049).

CONCLUSIONS

Tn-C may provide important prognostic information in bladder cancer depending on the expression pattern in the tumour stroma or cytoplasm of the tumour cells.

Pleomorphic adenoma and carcinoma ex pleomorphic adenoma: immunohistochemical demonstration of the association between tenascin expression and malignancy

AIMS

To investigate tenascin expression in salivary gland tumours. Tenascin is a matricellular protein that has been studied in several tumour types. Its expression has been correlated with tumour morphogenesis as well as with local invasiveness and tumour metastatic behaviour.

METHODS AND RESULTS

The distribution pattern of tenascin in a series of 63 pleomorphic adenomas (PA) and 20 carcinomas ex- pleomorphic adenoma (Ca ex PA) was studied immunohistochemically. Ten normal adult salivary glands were used as controls. Tenascin surrounded the excretory ducts of normal adult salivary gland tissue. It was absent in the basement membrane compartment of both benign and malignant mixed tumours. In the interstitial compartment of the extracellular matrix, the fibro-hyaline type expressed tenascin in a statistically significantly (P < 0.001) lower number of PA cases (25%) in comparison with both malignant and benign areas of Ca ex PA (75% and 90%, respectively). In the Ca ex PA group, a statistically significantly difference (P < 0.001) was found in the frequency of tenascin deposits around aggregates of neoplastic cells between metastasizing (73%) and non-metastasizing neoplasms (0%).

CONCLUSIONS

These findings strongly support the hypothesis that tenascin deposition is involved in the mechanisms of malignant transformation of pleomorphic adenomas into carcinomas as well as being associated with clinical disease progression.

Secretion of tenascin-C by cultured astrocytes: regulation of cell proliferation and process elongation

Tenascin-C (TNC), an extracellular matrix glycoprotein, is involved in tissue morphogenesis like embryogenesis, wound healing or tumorigenesis. Quiescent astroglia in long-term primary cultures are known to show rapid morphological changes after subculture and serum deprivation/re-addition (SSDR). To elucidate roles of TNC in the morphogenetic processes of cultured astrocytes, we have revealed morphological changes in association with soluble TNC contents in the medium and expression of TNC mRNA, TNC, glial fibrillary acidic protein (GFAP) and integrin beta1, one of its cell surface receptors, in glial cells after SSDR. Soluble TNC in the medium rapidly increased in amount at 4 h when GFAP-positive cells expressed TNC mRNA, TNC and integrin beta1. Cellular proliferation and growth occurred in colonies expressing TNC mRNA, TNC and integrin beta1 during the first 24 h. During the next 24 h, process elongation and cell migration occurred in association with increased GFAP expression and re-elevation of soluble TNC in the medium. Cell bodies became flat and larger with increased GFAP and reduced TNC expression at 72 h, while cultures became confluent with reduced GFAP and TNC expression at 96 h after SSDR. Functional blocking with anti-TNC antibody reduced cell proliferation and induced morphological change from a process-bearing slender shape to a flat and wide shape presumably due to increased cell adhesion. These findings strongly support the idea that endogenous TNC produced and released by astrocytes in response to serum stimulation induces their proliferation and process elongation through a paracrine/autocrine mechanism.