Collagens XV and XVIII show different expression and localisation in cutaneous squamous cell carcinoma: type XV appears in tumor stroma, while XVIII becomes upregulated in tumor cells and lost from microvessels

As the second most common skin malignancy, cutaneous squamous cell carcinoma (cSCC) is an increasing health concern, while its pathogenesis at molecular level remains largely unknown. We studied the expression and localisation of two homologous basement membrane (BM) collagens, types XV and XVIII, at different stages of cSCC. These collagens are involved in angiogenesis and tumorigenesis, but their role in cancer development is incompletely understood. Quantitative RT-PCR analysis revealed upregulation of collagen XVIII, but not collagen XV, in primary cSCC cells in comparison with normal human epidermal keratinocytes. In addition, the Ha-ras-transformed invasive cell line II-4 expressed high levels of collagen XVIII mRNA, indicating upregulation in the course of malignant transformation. Immunohistochemical analyses of a large human tissue microarray material showed that collagen XVIII is expressed by tumor cells from grade 1 onwards, while keratinocytes in normal skin and in premalignant lesions showed negative staining for it. Collagen XV appeared instead as deposits in the tumor stroma. Our findings in human cSCCs and in mouse cSCCs from the DMBA-TPA skin carcinogenesis model showed that collagen XVIII, but not collagen XV or the BM markers collagen IV or laminin, was selectively reduced in the tumor vasculature, and this decrease associated significantly with cancer progression. Our results demonstrate that collagens XV and XVIII are expressed in different sites of cSCC and may contribute in a distinct manner to processes related to cSCC tumorigenesis, identifying these collagens as potential biomarkers in the disease.

Clinical Efficiency of Topical Calcipotriol/Betamethasone Treatment in Psoriasis Relies on Suppression of the Inflammatory TNFα - IL-23 - IL-17 Axis

The effects of topical calcipotriol/betamethasone combination therapy and betamethasone monotherapy on inflammatory T-cell numbers and molecular markers were compared in patients with psoriasis. Combination therapy down-regulated the expression of tumour necrosis factor (TNF)-α, interleukin (IL)-23A, IL-17A, S100A7, CCL-20 and interferon (IFN)-γ in skin and TNF-α, IL-6, IL-23A, T-bet and IFN-γ in peripheral blood mononuclear cells (PBMCs). Betamethasone monotherapy had less effect. Expression of FoxP3 in both skin and PBMCs was down-regulated by calcipotriol/betamethasone, but not by betamethasone. Immunohistochemical analysis revealed that calcipotriol/betamethasone reduced the numbers of CD4+ and CD8+ T cells and Tregs in psoriatic lesions more than betamethasone. Flow cytometric analyses demonstrated that calcipotriol/betamethasone decreased the numbers of circulating CD8+ T cells, Tregs, skin-homing Th17 memory cells and Th22 memory cells, while betamethasone had little or no effect. Glucocorticoid receptors GRα and GRß were expressed in psoriatic skin. In conclusion, calcipotriol increases the immunosuppressive power of betamethasone by suppressing the inflammatory TNF-α - IL-23 - IL-17 axis.

Significant Role of Collagen XVII And Integrin β4 in Migration and Invasion of The Less Aggressive Squamous Cell Carcinoma Cells

Collagen XVII and integrin α6β4 have well-established roles as epithelial adhesion molecules. Their binding partner laminin 332 as well as integrin α6β4 are largely recognized to promote invasion and metastasis in various cancers, and collagen XVII is essential for the survival of colon and lung cancer stem cells. We have studied the expression of laminin γ2, collagen XVII and integrin β4 in tissue microarray samples of squamous cell carcinoma (SCC) and its precursors, actinic keratosis and Bowen's disease. The expression of laminin γ2 was highest in SCC samples, whereas the expression of collagen XVII and integrin β4 varied greatly in SCC and its precursors. Collagen XVII and integrin β4 were also expressed in SCC cell lines. Virus-mediated RNAi knockdown of collagen XVII and integrin β4 reduced the migration of less aggressive SCC-25 cells in horizontal scratch wound healing assay. Additionally, in a 3D organotypic myoma invasion assay the loss of collagen XVII or integrin β4 suppressed equally the migration and invasion of SCC-25 cells whereas there was no effect on the most aggressive HSC-3 cells. Variable expression patterns and results in migration and invasion assays suggest that collagen XVII and integrin β4 contribute to SCC tumorigenesis.

Expression of Glucocorticoid Receptors GRα and GRβ in Bullous Pemphigoid

First-line treatments of bullous pemphigoid (BP) are topical and systemic glucocorticoids (GC). The actions of GC are mediated by glucocorticoid receptors (GR), which exist in several isoforms, of which GRα and GRβ are the most important. In many inflammatory diseases, up-regulation of GRβ is associated with GC insensitivity. The aims of this study were to determine the expression of GRα and GRβ in patients with BP and to investigate the effect of prednisolone treatment on the expression of GR isoforms in BP. Quantitative real-time PCR (qPCR) analysis demonstrated that GR isoform mRNAs are expressed in peripheral blood mononuclear cells (PBMC) from patients with BP. Expression of GRα and GRβ protein was confirmed by immunohistochemical staining of BP skin biopsies and by Western blot analysis and flow cytometric analysis of PBMCs. During prednisolone treatment, GRα and GRβ expression varied markedly, but changes were not suitable as a clinical marker of GC sensitivity in patients with BP.

Biallelic Mutations in PDE10A Lead to Loss of Striatal PDE10A and a Hyperkinetic Movement Disorder with Onset in Infancy

Deficits in the basal ganglia pathways modulating cortical motor activity underlie both Parkinson disease (PD) and Huntington disease (HD). Phosphodiesterase 10A (PDE10A) is enriched in the striatum, and animal data suggest that it is a key regulator of this circuitry. Here, we report on germline PDE10A mutations in eight individuals from two families affected by a hyperkinetic movement disorder due to homozygous mutations c.320A>G (p.Tyr107Cys) and c.346G>C (p.Ala116Pro). Both mutations lead to a reduction in PDE10A levels in recombinant cellular systems, and critically, positron-emission-tomography (PET) studies with a specific PDE10A ligand confirmed that the p.Tyr107Cys variant also reduced striatal PDE10A levels in one of the affected individuals. A knock-in mouse model carrying the homologous p.Tyr97Cys variant had decreased striatal PDE10A and also displayed motor abnormalities. Striatal preparations from this animal had an impaired capacity to degrade cyclic adenosine monophosphate (cAMP) and a blunted pharmacological response to PDE10A inhibitors. These observations highlight the critical role of PDE10A in motor control across species.

Bullous Pemphigoid With a Dual Pattern of Glomerular Immune Complex Disease

A 75-year-old man presented with a blistering skin disease and nephrotic syndrome. Bullous pemphigoid was diagnosed by linear immunoglobulin G (IgG) and C3 staining along the basement membrane zone of a skin biopsy specimen and by the presence of circulating IgG recognizing the 180-kDa bullous pemphigoid antigen (BP180; type XVII collagen). A kidney biopsy specimen showed endocapillary inflammation without crescents. Direct immunofluorescence showed strong IgG and C3 staining in a combined granular and linear pattern along the glomerular basement membrane. Electron microscopy showed subepithelial deposits. In serum, no antibodies against the Goodpasture antigen (type IV collagen) or phospholipase A2 receptor were detected. Indirect immunofluorescence studies using the patient's serum showed a strikingly linear but not granular IgG pattern along the epithelial basement membranes of monkey esophagus and kidney. Although type XVII collagen was recently identified in the glomerulus, the patient's serum did not produce a 180-kDa band on immunoblot of kidney tissue and still stained glomeruli of BP180 knockout mice by indirect immunofluorescence. The patient was treated with prednisone and azathioprine, which resulted in complete remission of skin and kidney manifestations. Although bullous pemphigoid has been reported previously in association with anti-glomerular basement membrane disease or membranous nephropathy, this case demonstrates both elements in 1 patient. This concurrence and the linear pattern on indirect immunofluorescence support the possibility of cross-reactive or parallel autoantibodies to basement membranes with a secondary membranous component.

Deletion of the major bullous pemphigoid epitope region of collagen XVII induces blistering, autoimmunization, and itching in mice

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering skin disease with a characteristic of pruritus and blistering. BP patients carry inflammation-triggering autoantibodies against the collagen XVII (ColXVII, also known as BP180) juxtamembraneous extracellular noncollagenous 16A (NC16A) domain involved in ectodomain shedding. Deletion of the corresponding NC14A region in a genetically modified mouse model (ΔNC14A) decreased the amount of ColXVII in skin, but it did not prevent ectodomain shedding. Newborn ΔNC14A mice had no macroscopic phenotypic changes. However, subepidermal microblisters, rudimentary hemidesmosomes, and loose basement membrane zone were observed by microscopy. ΔNC14A mice grow normally, but at around 3 months of age they start to scratch themselves and develop crusted erosions. Furthermore, perilesional eosinophilic infiltrations in the skin, eosinophilia, and elevated serum IgE levels are detected. Despite the removal of the major BP epitope region, ΔNC14A mice developed IgG and IgA autoantibodies with subepidermal reactivity, indicating autoimmunization against a dermo-epidermal junction component. Moreover, IgG autoantibodies recognized a 180-kDa keratinocyte protein, which was sensitive to collagenase digestion. We show here that ΔNC14A mice provide a highly reproducible BP-related mouse model with spontaneous breakage of self-tolerance and development of autoantibodies.

Collagen XVII expression correlates with the invasion and metastasis of colorectal cancer

Collagen XVII has a well-established role as an adhesion molecule and a cell surface receptor located in the type I hemidesmosome of stratified epithelia. Its ectodomain is constitutively shed from the cell surface and suggested to regulate the adhesion, migration, and signaling of cutaneous epithelial cells. Collagen XVII was not previously thought to be expressed by colon epithelial cells. Immunohistochemical analysis of tissue microarray samples of 141 cases of colorectal carcinoma showed that collagen XVII is expressed in normal human colonic mucosa and colorectal carcinoma. In colorectal carcinoma, increased collagen XVII expression was significantly associated with higher TNM stage. It also correlated with infiltrative growth pattern and tumor budding as well as lymph node and distant metastasis. Increased collagen XVII expression was associated with decreased disease-free and cancer-specific survival. Immunofluorescence staining of collagen XVII and its well-known binding partner laminin γ2 chain demonstrated a partial colocalization in normal and tumor tissue. In vitro, the overexpression of murine collagen XVII promoted the invasion of CaCo-2 colon carcinoma cells through Matrigel (BD Biosciences; Bedford, MA). To conclude, this study reports for the first time the expression of collagen XVII in colon epithelium and the association of increased collagen XVII immunoexpression with poor outcome in colorectal carcinoma.

Transmembrane collagen XVII modulates integrin dependent keratinocyte migration via PI3K/Rac1 signaling

The hemidesmosomal transmembrane component collagen XVII (ColXVII) plays an important role in the anchorage of the epidermis to the underlying basement membrane. However, this adhesion protein seems to be also involved in the regulation of keratinocyte migration, since its expression in these cells is strongly elevated during reepithelialization of acute wounds and in the invasive front of squamous cell carcinoma, while its absence in ColXVII-deficient keratinocytes leads to altered cell motility. Using a genetic model of murine Col17a1⁻/⁻ keratinocytes we elucidated ColXVII mediated signaling pathways in cell adhesion and migration. Col17a1⁻/⁻ keratinocytes exhibited increased spreading on laminin 332 and accelerated, but less directed cell motility. These effects were accompanied by increased expression of the integrin subunits β4 and β1. The migratory phenotype, as evidenced by formation of multiple unstable lamellipodia, was associated with enhanced phosphoinositide 3-kinase (PI3K) activity. Dissection of the signaling pathway uncovered enhanced phosphorylation of the β4 integrin subunit and the focal adhesion kinase (FAK) as activators of PI3K. This resulted in elevated Rac1 activity as a downstream consequence. These results provide mechanistic evidence that ColXVII coordinates keratinocyte adhesion and directed motility by interfering integrin dependent PI3K activation and by stabilizing lamellipodia at the leading edge of reepithelializing wounds and in invasive squamous cell carcinoma.

Gestational pemphigoid: placental morphology and function

Gestational pemphigoid (PG), a very rare pregnancy-associated bullous dermatosis, is associated with adverse pregnancy outcome (miscarriage, preterm delivery, foetal growth restriction). The major antigen in PG is collagen XVII (BP180). PG autoantibodies cross-react with collagen XVII in the skin and have been suggested to cause placental failure. On this basis, we evaluated clinical outcome and morphological and functional placental data of 12 PG pregnancies in Finland during 2002 to 2011. The placental-to-birth weight ratio was abnormal in half of the pregnancies. Ultrastructural analysis of PG placentas showed detachment of basement membranes and undeveloped hemidesmosomes. Ultrasound evaluations of placental function prior to delivery were normal in all but one pregnancy. Three (25%) neonates were delivered preterm after 35 gestational weeks and one pregnancy was complicated by preeclampsia and severe foetal growth restriction. Neonatal outcome was uneventful in every case. In conclusion, in pregnancies complicated by PG, slight alteration in ultrastructural morphology of the placental basement membrane was detected, but umbilical artery Doppler evaluation indicated no functional placental changes.

Transmembrane collagen XVII is a novel component of the glomerular filtration barrier

The kidney filtration barrier consists of the capillary endothelium, the glomerular basement membrane and the slit diaphragm localized between foot processes of neighbouring podocytes. We report that collagen XVII, a transmembrane molecule known to be required for epithelial adhesion, is expressed in podocytes of normal human and mouse kidneys and in endothelial cells of the glomerular filtration barrier. Immunoelectron microscopy has revealed that collagen XVII is localized in foot processes of podocytes and in the glomerular basement membrane. Its role in kidney has been analysed in knockout mice, which survive to birth but have high neonatal mortality and skin blistering and structural abnormalities in their glomeruli. Morphometric analysis has shown increases in glomerular volume fraction and surface densities of knockout kidneys, indicating an increased glomerular amount in the cortex. Collagen XVII deficiency causes effacement of podocyte foot processes; however, major slit diaphragm disruptions have not been detected. The glomerular basement membrane is split in areas in which glomerular and endothelial basement membranes meet. Differences in the expression of collagen IV, integrins α3 or β1, laminin α5 and nephrin have not been observed in mutant mice compared with controls. We propose that collagen XVII has a function in the attachment of podocyte foot processes to the glomerular basement membrane. It probably contributes to podocyte maturation and might have a role in glomerular filtration.

Tumor tissue inhibitor of metalloproteinases-1 (TIMP-1) in hormone-independent breast cancer might originate in stromal cells, and improves stratification of prognosis together with nodal status

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is shown to be a potential marker for poor prognosis in breast cancer, but the biology of TIMP-1 is only partially understood. In this study, TIMP-1 production was studied in a co-culture model of hormone-independent breast cancer cell lines and mesenchymal stem cells mimicking the stromal components of the tumor. In addition, the prognostic value of TIMP-1 was histologically evaluated in a clinical material of 168 patients with hormone-independent breast tumors. The hormone-independent breast cancer (BC) cell lines MDA-MB-231, M4A4 and NM2C5 did not produce TIMP-1 protein in measureable quantities. Six tested primary mesenchymal stem cell lines all produced TIMP-1. Co-culturing of mesenchymal stem cells and breast cancer cells resulted in positive immunocytochemical diffuse staining for TIMP-1 for both cell types. Culturing breast cancer cells with MSC-conditioned media resulted in a positive cytoplasmic immunoreactivity for TIMP-1, and TIMP-1 protein concentration in cell lysates increased 2.7-fold (range 1.1-4.7). The TIMP-1 mRNA levels remained unaffected in BC cells. This might suggest that breast cancer cells can take up TIMP-1 produced by stromal cells and are thus displaying cellular immunoreactivity. In addition, TIMP-1 was shown to improve stratification of prognosis in clinical material.

Pemphigoid gestationis autoantigen, transmembrane collagen XVII, promotes the migration of cytotrophoblastic cells of placenta and is a structural component of fetal membranes

In pemphigoid gestationis (PG), autoantibodies target collagen XVII, a hemidesmosomal transmembrane protein, which is an important element in cutaneous epithelial adhesion and signalling. We report that collagen XVII is expressed in the first trimester and term syncytial and cytotrophoblastic cells of normal placenta and in epithelial cells of amniotic membrane. Immunoelectron microscopy confirmed the localization of collagen XVII to the hemidesmosomes of amniotic epithelium. Examination of three PG placentas showed mild villitis, but there were no differences between collagen XVII expression levels or immunostaining signals as compared to normal placenta. Collagen XVII expression was also detected in cultured extravillous trophoblast HTR-8/SVneo cells, where collagen XVII expression was upregulated by PMA and TGF-beta1. Interestingly, the presence of Col15, the cell migration domain of collagen XVII, induced the migration of HTR-8/SVneo cells in transmigration assay. Analysis of amniotic fluid samples at different gestational weeks revealed that a large quantity of collagen XVII ectodomain was shed into amniotic fluid throughout pregnancy. Biochemical and immunoblotting analysis indicated that the ectodomain in amniotic fluid is structurally very similar to the ectodomain produced by cultured keratinocytes. Cultured cells from amniotic fluid samples also expressed collagen XVII. Our results suggest that collagen XVII may contribute to the invasion of extravillous trophoblasts during placental development and is also required for the integrity of amniotic basement membrane. Although the exact pathomechanism of PG is still largely unknown, the clinical symptoms of PG are initiated after the expression of collagen XVII in placenta during the first trimester of pregnancy.

ADAMTSL3/punctin-2, a gene frequently mutated in colorectal tumors, is widely expressed in normal and malignant epithelial cells, vascular endothelial cells and other cell types, and its mRNA is reduced in colon cancer

ADAMTSL3/punctin-2 is a secreted glycoprotein that resembles the ADAMTS proteases. Recently, identification of frequent ADAMTSL3 mutations in colorectal cancer suggested it might have a regulatory role in cellular homeostasis in colorectal epithelium or in pathways to colorectal malignancy. Here, we used in situ hybridization to validate ADAMTSL3 antibodies for IHC of a variety of normal and malignant tissues, including colon cancer. Quantitative real-time PCR (RTQ-PCR) was used to compare mRNA expression levels in colon carcinoma (n = 10) and adjacent normal colon. ADAMTSL3 is expressed in epithelial cells of the colon, fallopian tube, skin, breast, prostate, epididymis, liver, pancreatic islets and bile ducts, as well as by vascular endothelial cells, smooth muscle cells, fibroblasts, cortical and ganglionic neurons and cardiac myocytes. Malignant epithelial cells in colon cancer, as well as breast, prostate, renal and skin tumors expressed ADAMTSL3. Normal colon showed stronger immunostaining of surface than basal crypt epithelium and staining of a variety of cells within the lamina propria and submucosa. Colon carcinomas demonstrated weaker staining in tumor cells than normal colon epithelium and weak stromal staining. RTQ-PCR comparison of ADAMTSL3 mRNA in colon carcinoma and adjacent normal colon demonstrated a statistically significant reduction in the tumors, possibly reflecting their decreased stromal content and lack of complete differentiation of tumor samples. The major findings of these studies are that ADAMTSL3 is expressed in numerous tissues, suggesting a broader regulatory role than in colorectal epithelium alone, and that colorectal cancer has both structural mutations as well as decreased expression of ADAMTSL3.

Collagen XVII is expressed in human CNS neurons

Type XVII collagen (collagen XVII) is a component of hemidesmosomes, which connect epithelial cells to the underlying basement membrane. Previously, an association has been suggested between neurological disorders and the skin disease bullous pemphigoid, where autoimmunity is directed against collagen XVII. Furthermore, the lack of alpha6 integrin, a ligand of collagen XVII, has been implicated in defects of cortical organization in the mouse brain. In this study, we demonstrate for the first time the presence of collagen XVII in neurons of the human brain by in situ hybridisation, immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). We propose that collagen XVII may be involved in the pathogenesis of various disorders affecting neuronal migration or synaptic plasticity.

Molecular mechanisms of junctional epidermolysis bullosa: Col 15 domain mutations decrease the thermal stability of collagen XVII

Mutations in the collagen XVII gene, COL17A1, are associated with junctional epidermolysis bullosa. Most COL17A1 mutations lead to a premature termination codon (PTC), whereas only a few mutations result in amino acid substitutions or deletions. We describe here two novel glycine substitutions, G609D and G612R, and a splice site mutation resulting in a deletion of three Gly-X-Y amino acid triplets. In order to investigate the molecular pathomechanisms of non-PTC mutations, G609D and G612R and two previously known substitutions, G627V and G633, and deletion of the amino acids 779-787 were introduced into recombinant collagen XVII. The thermal stability of the mutated collagens was assessed using trypsin digestions at incremental temperatures. All the four glycine substitutions significantly destabilized the ectodomain of collagen XVII, which manifested as 16 degrees C-20 degrees C lower T(m) (midpoint of the helix-to-coil transition). These results were supported by secondary structure predictions, which suggested interruptions of the collagenous triple helix within the largest collagenous domain, Col15. In contrast, deletion of the three full Gly-X-Y triplets, amino acids 779-787, had no overall effect on the stability of the ectodomain, as the deletion was in register with the triplet structure and also generated compensatory changes in the NC15 domain.

Expression of matrix metalloproteinases (MMP-1 and -2) and their inhibitors (TIMP-1, -2 and -3) in oral lichen planus, dysplasia, squamous cell carcinoma and lymph node metastasis

Although matrix metalloproteinases (MMPs) are among the potential key mediators of cancer invasion, their involvement in premalignant lesions and conditions is not clarified. Therefore, we studied, using in situ hybridization, immunohistochemistry and zymography the expression and distribution of MMP-1 and -2, and their tissue inhibitors (TIMPs -1, -2 and -3) in oral squamous cell carcinomas (SCC) and lymph node metastases as well as in oral lichen planus, epithelial dysplasias and normal buccal mucosa. In oral SCC and lymph node metastasis, MMP-1 mRNA was detected in fibroblastic cells of tumoral stroma. In two out of ten carcinomas studied, the peripheral cells of neoplastic islands were also positive. MMP-2 mRNA expression was noted in fibroblasts surrounding the carcinoma cells, and no signal in carcinoma cells was detected. A clear TIMP-3 mRNA expression was seen in stromal cells surrounding the neoplastic islands in all SCCs and lymph node metastases studied. TIMP-1 mRNA was detected in some stromal cells surrounding the neoplastic islands, whereas the mRNA expression for TIMP-2 was negligible. On the other hand, expression of MMPs and TIMPs was consistently low in oral epithelial dysplasias, lichen planus and normal mucosa. In certain epithelial dysplasias and lichen planus, MMP-1 and -2 mRNA expressions were detected in few fibroblasts under the basement membrane zone, but normal mucosa was completely negative. In SCC and lymph node metastasis, a detectable immunostaining for MMP-1 in stromal cells and in some carcinoma cells was observed. MMP-2 immunoreactivity was detected in the peripheral cell layer in neoplastic islands and in some fibroblast-like cells of tumoral stroma. Immunostaining for TIMP-3 was detected in stromal cells surrounding the neoplastic islands. A weak positive staining for TIMP-1 was located in tumoral stroma, whereas the immunostaining for TIMP-2 was negative. Using zymography, elevated levels of MMP-2 and MMP-9 were observed in carcinoma samples in comparison with lichen planus or normal oral mucosa. Our results indicate that the studied MMPs and TIMPs are clearly up-regulated during invasion in oral SCC. However, there was also a clear, although weak, up-regulation of the expression of the MMPs but not TIMPs in some of the lichen planus and dysplastic lesions.

Production of membrane-type matrix metalloproteinase-1 (MT-MMP-1) in early human placenta. A possible role in placental implantation?

The extracellular matrix proteolytic machinery is known to play a major role in trophoblast invasion, a process that shares similar features with the pathology of tumor invasion. In this study we investigated the expression of the recently described membrane-type matrix metalloproteinase-1 (MT-MMP-1; MMP-14) in early human placenta and decidual membrane to determine whether it might play a role in invasion. With in situ hybridization, the cytotrophoblasts of trophoblastic columns and the infiltrating intermediate trophoblasts in the decidual membrane were found to be the main producers of MT-MMP-1 mRNA. Gene expression was also seen in the villous double-layered trophoblastic epithelium and in the decidual cells of the decidual membrane. In endothelial and fibroblastic cells, however, the hybridization signal was either very weak or nonexistent. Immunohistochemical analysis and immunoelectron microscopy correlated well with the in situ hybridization findings. The most significant exception to this consisted of pericytes of spiral arteries, which appeared to lack MT-MMP-1 mRNA but showed intensive intracytoplasmic staining for the antigen. Our results show that MT-MMP-1 mRNA production is highly characteristic of intermediate trophoblasts, and MT-MMP-1 may have general importance in the tissue organization of early human placenta. We propose that MT-MMP-1 could be one of the key enzymes in the process of trophoblast invasion, acting alone or as a cell-surface activator of other proteinases.

mRNA expressions of TIMP-1, -2, and -3 and 92-KD type IV collagenase in early human placenta and decidual membrane as studied by in situ hybridization

Cytotrophoblasts of early placenta invade the decidual membrane, gestational endometrium, and spiral arteries during early pregnancy. Unlike tumor invasion, this physiological invasion is well controlled, although its molecular mechanisms are largely unknown. We have previously shown that cytotrophoblasts synthesize significant mRNAs for 72-KD Type IV collagenase, laminin, and Type IV collagen, proteins implicated in extracellular matrix turnover and migration. In this study we used in situ hybridization and immunohistochemistry to investigate the mRNA expression pattern of 92-KD Type IV collagenase and the matix metalloproteinase inhibitors TIMP-1, TIMP-2, and TIMP-3 in early human placenta and decidual membrane. mRNAs for 92-KD Type IV collagenase, TIMP-1, TIMP-2, and TIMP-3 were found in the cells of cytotrophoblastic columns, the endothelial and fibroblastic stromal cells of villi, and the large decidualized cells of decidual membrane. TIMP-1 expression was notably accentuated in the fibroblasts of fibrotic villi. In the decidual membrane, the signals for 92-KD Type IV collagenase and TIMP-1 mRNA were particularly strong around the glandular structures. The trophoblastic epithelium of villi and the epithelial cells of decidual glands showed a signal for 92-KD Type IV collagenase and TIMP-2, but not for TIMP-1 or TIMP-3. The coincidental expression of the proteolytic 92-KD Type IV collagenase and inhibitors TIMP-1, TIMP-2, and TIMP-3 generally in the same cells suggests that the activity of 92-KD Type IV collagenase, which is regulated by TIMPs, plays an important role in placental tissue organization and in the invasion of trophoblastic cells into the uterine wall.

Expression of the tissue metalloproteinase inhibitors TIMP-1 and TIMP-2 in malignant fibrous histiocytomas and dermatofibromas as studied by in situ hybridization and immunohistochemistry

The expression of tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) was studied in eight malignant fibrous histiocytomas (MFH) and in eight dermatofibromas (DF) using in situ hybridization methods (ISH). Immunohistochemical stainings were also performed using corresponding antibodies to TIMP-1 and TIMP-2. In ISH the neoplastic cells of MFHs showed a high level of expression for both TIMP-1 and TIMP-2 mRNAs. The cells usually expressed similarly both TIMPs, except for osteoclast-like giant cells, which showed a distinct signal for TIMP-2 but not for TIMP-1. A distinctly lower level of both TIMP-1 and TIMP-2 mRNAs was seen in DFs. Immunohistochemical stainings were concordant with the results obtained by ISH. The findings suggest that the behavior of MFHs and DFs is not directly or solely dependent on the quantity of type IV collagenase inhibitors. The increased TIMP synthesis in MFHs might represent a chaotic response of malignant cells to increased matrix degradation. Alternatively, it may reflect a deranged communication between type IV collagenases and TIMPs in malignant tissues.

72 KD and 92 KD type IV collagenase, type IV collagen, and laminin mRNAs in breast cancer: a study by in situ hybridization

It is widely accepted that basement membrane (BM) components are synthesized by epithelial cells and that production of BM-degrading proteases by cancer cells is necessary for invasive growth. In this study we used nucleic acid in situ hybridization (ISH) to investigate the presence of mRNAs for 72 KD and 92 KD Type IV collagenase, alpha 1 (IV) chain of Type IV collagen, and laminin B1 chain in 20 breast carcinomas of various histological types. The mRNA signals for 72 KD Type IV collagenase, Type IV collagen, and laminin were much more abundant in stromal fibroblasts and endothelial cells than in carcinoma cells. The signal for 92 KD Type IV collagenase mRNA was strong in carcinoma cells and considerably weaker in stromal fibroblasts and endothelial cells. Labeling for 72 KD and 92 KD Type IV collagenase mRNA was also found in benign fibroadenomas and for 92 KD Type IV collagenase in non-neoplastic ducts and acini. The results indicate that stromal cells have a more important role in the synthesis and degradation of BMs in breast carcinomas than previously thought and that production of these enzymes is not restricted to malignancy.

Expression of 72 kilodalton type IV collagenase (gelatinase A) in benign and malignant ovarian tumors

BACKGROUND

72 Kilodalton (kd) type IV collagenase is a matrix metalloproteinase that specifically cleaves type IV collagen molecules. The enzyme has been postulated to have an important role in the invasion and spread of malignant tumors.

EXPERIMENTAL DESIGN

In situ hybridization was used to study the expression of the 72 kd type IV collagenase mRNA in 24 benign, 2 semimalignant, and 15 malignant ovarian tumors and in 5 metastases of ovarian serous adenocarcinomas. The results were correlated with the expression of the mRNA for the alpha 1(IV) chain of type IV collagen and with the corresponding immunohistochemical distribution of the enzyme.

RESULTS

The results showed that the more malignant an ovarian tumor was, the more clearly mRNA expressions for both 72 kd type IV collagenase and the alpha 1(IV) chain could be detected in tumor cells. The expression of both types of mRNAs was localized within the cells of tumor stroma and occurred mainly in fibroblasts and vascular endothelial cells. Epithelial tumor cells only rarely expressed these mRNAs. Immunohistochemical stainings localized the 72 kd collagenase as well to the stromal cells as to the epithelial cells of both benign and malignant tumors.

CONCLUSIONS

The findings indicate that genes for the 72 kd type IV collagenase and for its substrate are simultaneously active in the same cells of the tumor stroma. The difference in the in situ hybridization and immunohistochemical findings could be explained by a possible variation in the metabolic balance between synthesis and accumulation of the protein in different cell types. It can also be proposed that the activity of the 72 kd type IV collagenase would be mediated through a receptor-like mechanism present on epithelial cells which could bind the 72 kd type IV collagenase synthesized elsewhere. There is also a possibility that the gelatinolytic activity of the mesenchymally synthesized 72 kd type IV collagenase would be consumed to degrade extracellular matrix proteins other than basement membranes.

Simultaneous expression of 70 kilodalton type IV collagenase and type IV collagen alpha 1 (IV) chain genes by cells of early human placenta and gestational endometrium

BACKGROUND

In this study we used in situ hybridization to investigate the expression of the genes 70 kilodalton (kd) collagenase and the alpha 1(IV) collagen chain of type IV collagen in cells of early human placenta and gestational endometrium.

EXPERIMENTAL DESIGN

The aim was to study the spatial distribution of these gene expressions within a developing tissue which possesses physiologic invasive potential. The results obtained for the 70 kd type IV collagenase mRNA expression were also compared with the immunohistochemical distribution of the corresponding antigen.

RESULTS

Expression of mRNAs for these proteins was found in cells of trophoblastic columns, stromal cells of villi and in cells of decidua and endometrial stroma. The only differences between the expressions was the lower level of signals for 70 kd type IV collagenase in fibroblastic stromal cells and endothelial cells of villi and in the pericytic cells of spiral arteries. Otherwise the results for both types of mRNA were comparable. We also studied the immunohistochemical distribution of the 70 kd type IV collagenase using specific monoclonal antibodies against the enzyme. Immunohistochemistry supported well the findings obtained by in situ hybridization.

CONCLUSIONS

The results indicate that the genes for the 70 kd type IV collagenase and for the alpha 1(IV) collagen chain are simultaneously active in cells of placenta and gestational endometrium and the same cells which produce type IV collagen also can produce the cleaving enzyme, the 70 kd type IV collagenase. The results also show that the cytotrophoblastic cells, which during early pregnancy invade the extracellular matrix and spiral arteries of uterine wall contain significant amount of mRNA for the 70 kd type IV collagenase. This finding supports the concept that the 70 kd type IV collagenase would be important for invasion, and in the case of this study, also for the physiologic invasion of placental cytotrophoblasts.

Molecular cloning of murine 72-kDa type IV collagenase and its expression during mouse development

We report the isolation of a cDNA clone providing the first and complete sequence of mouse 72-kDa type IV collagenase. The clone contains 2800 nucleotides with a 1986-nucleotide open reading frame coding for 662 amino acids. The amino acid sequence includes a 29-residue signal peptide, an 80-residue propeptide, and a 553-residue enzyme proper. The sequence identity between the mouse and human enzymes is 96% with all cysteine residues conserved. The carboxyl-terminal domain of the mouse enzyme contains two more residues than the human enzyme. Northern hybridization analysis revealed considerable expression of the enzyme gene in newborn mouse lung, heart, kidney, and psoas muscle tissues, whereas only weak or no signals were observed in liver, spleen, and brain. Expression of the gene was substantially reduced in the same tissues of 3-month-old mice. In situ hybridization analysis of 72-kDa type IV collagenase expression in 10-15-day-old mouse embryos showed that the gene was intensely expressed in mesenchymal cells. Brain and surface ectoderm were completely negative. The epithelial tissue component of developing organs was negative with the exception of salivary gland. Although the expression varied somewhat between different mesenchymal tissues, no temporal or spatial changes could be associated with the advancement of epithelial branching morphogenesis. These findings together with our previous data on the expression of 72-kDa type IV collagenase in human tumors indicate that this enzyme has some very specific roles both in the physiological and pathological degradation of extracellular matrix. Furthermore, it has become clear that the closely related 92-kDa type IV collagenase differs completely with respect to expression pattern as well as gene regulation. The mouse cDNA clones reported in this study may provide important tools unraveling the actual roles of these enzymes in vivo.

Localization of messenger RNA for Mr 72,000 and 92,000 type IV collagenases in human skin cancers by in situ hybridization

We have examined the expression of 2 type IV collagen degrading enzymes (Mr 72,000 and 92,000 type IV collagenases) in human skin cancer by in situ hybridization. In all cases of infiltrating carcinomas of squamous cell (9 of 9) and basal cell (5 of 5) types, messenger RNA for the Mr 72,000 type IV collagenase was present in numerous fibroblasts. These were especially abundant in the stroma adjacent to the invasive tumor nodules. Malignant cells were negative for mRNA for the Mr 72,000 enzyme in all cases as were all other epithelial as well as endothelial cells. mRNA for the Mr 92,000 type IV collagenase was present in all 9 squamous cell and in 3 of the 5 basal cell carcinomas. In all these cases, a subpopulation of tissue macrophages was found to be positive, while malignant cells showed a signal for Mr 92,000 type IV collagenase in 6 of the squamous cell carcinomas but in none of the basal cell carcinomas. In all cases, the signal for this mRNA was confined to cells located at the tumoral/stromal interface or in the close vicinity of tumor nodules. No mRNA for any of the 2 collagenases was detected in 3 biopsies of normal skin. In vitro studies have indicated that collagenases are involved in the degradation of the extracellular matrix during cancer invasion. The present findings are consistent with such a role of the Mr 72,000 and 92,000 type IV collagenases in squamous and basal cell carcinomas in situ. The findings also demonstrate that degradative enzymes are not necessarily produced by the malignant cells themselves but may be generated by induction or recruitment of nonmalignant stromal cells.