E-cadherin/α-catenin deregulated co-expression in thyroid carcinoma based on tissue microarray digital image analysis.

PURPOSE: Deregulation of cell-to-cell adhesion molecules is a common and also critical genetic event in epithelial malignancies leading to an increasing metastatic potential. Among them, e-cadherin and catenins--especially α and ß--, act as oncogenes during the carcinogenetic process affecting specific signaling transduction pathways (i.e. Wnt/ b-catenin). Concerning thyroid carcinoma, decreased or loss of expression in these proteins seems to affect the biological behavior of the neoplasm increasing its aggressiveness. The aim of this study was to investigate the deregulation of e-cadherin/α-catenin complex in thyroid carcinomas. METHODS: Thirty-five paraffin-embedded tissue samples including thyroid carcinomas (N=20) and also 15 cases of benign follicular nodules were cored at 1 mm diameter and transferred to a microarray block. Immunohistochemistry (IHC) was performed using anti-e-cadherin/α-catenin antibodies. Digital image analysis was also implemented for measuring the corresponding protein expression levels. RESULTS: E-cadherin/α-catenin protein expression demonstrated a significant progressive decrease regarding benign and malignant lesions (p=0.001). Simultaneous e-cadherin/α-catenin reduced or loss of expression was observed in 10/20 (50%) cancer cases correlated to advanced stage (especially nodal metastasis) of the examined tumours (p=0.02). Concerning the histological type, combined loss of e-cadherin/α-catenin expression was predominantly associated with follicular and anaplastic histology (p=0.001). Interestingly, α-catenin protein expression pattern was significantly correlated with the grade of differentiation of the examined malignancies (p=0.01). CONCLUSIONS: Progressive loss of e-cadherin mainly and also α-catenin expression is associated with an aggressive phenotype (low differentiation, increased metastatic activity/advanced stage) in thyroid carcinomas. Based on their aberrant protein expression, novel agents have been developed for restoring their normal function.

Deep imaging of bone marrow shows non-dividing stem cells are mainly perisinusoidal.

Haematopoietic stem cells (HSCs) reside in a perivascular niche but the specific location of this niche remains controversial. HSCs are rare and few can be found in thin tissue sections or upon live imaging, making it difficult to comprehensively localize dividing and non-dividing HSCs. Here, using a green fluorescent protein (GFP) knock-in for the gene Ctnnal1 in mice (hereafter denoted as α-catulin(GFP)), we discover that α-catulin(GFP) is expressed by only 0.02% of bone marrow haematopoietic cells, including almost all HSCs. We find that approximately 30% of α-catulin-GFP(+)c-kit(+) cells give long-term multilineage reconstitution of irradiated mice, indicating that α-catulin-GFP(+)c-kit(+) cells are comparable in HSC purity to cells obtained using the best markers currently available. We optically cleared the bone marrow to perform deep confocal imaging, allowing us to image thousands of α-catulin-GFP(+)c-kit(+) cells and to digitally reconstruct large segments of bone marrow. The distribution of α-catulin-GFP(+)c-kit(+) cells indicated that HSCs were more common in central marrow than near bone surfaces, and in the diaphysis relative to the metaphysis. Nearly all HSCs contacted leptin receptor positive (Lepr(+)) and Cxcl12(high) niche cells, and approximately 85% of HSCs were within 10 µm of a sinusoidal blood vessel. Most HSCs, both dividing (Ki-67(+)) and non-dividing (Ki-67(-)), were distant from arterioles, transition zone vessels, and bone surfaces. Dividing and non-dividing HSCs thus reside mainly in perisinusoidal niches with Lepr(+)Cxcl12(high) cells throughout the bone marrow.

The Lauren classification highlights the role of epithelial-to-mesenchymal transition in gastric carcinogenesis: an immunohistochemistry study of the STAT3 and adhesion molecules expression.

BACKGROUND AND AIMS: Despite some recent advances, gastric cancer remains an important cause of death at world level. This indicates an absence of therapeutic options, stemming from the limited understanding of the molecular mechanisms involved in carcinogenesis. Nearly fifty years ago Lauren classified gastric cancers, according to the morphological aspect, as intestinal or diffuse. The phenotype of the cells indicates the presence of different molecular mechanisms, which can be approached in the light of recent data and identified with the help of current techniques. The best described are the germline/somatic mutations or the hypermethylations of the E-cadherin 1 CDH1 gene promotor. METHODS: We analyzed 195 gastric tumors,120 intestinal and 75 diffuse type, using immunohistochemistry (tissue microarray TMA method) for pStat3Tyr705, E-cadherin, α-catenin and ß-catenin; 985 spots of gastric tumors, distributed on 4 TMA blocks were analyzed. For pStat3Tyr705 we took the nuclear staining into account and for the adhesion molecules, membrane staining. RESULTS: In our study, in the diffuse type gastric cancer, pStat3Tyr705 nuclear expression was statistically significantly increased (p=0.003). Also we observed a decreased expression of the adhesion molecules in the same type of gastric cancer (E-cadherin p<0.0001, α-catenin p<0.0001, ß-catenin p<0.0001), suggesting that epithelial-to-mesenchymal transition (EMT) may be involved not only in gastric carcinogenesis, but also in resistance to treatment. CONCLUSION: The Stat3 role has been recently highlighted in carcinogenesis of the diffuse type of gastric cancer. We found that the morphological features of the diffuse type also suggest the involvement of EMT in this type of gastric cancer. Therefore, targeting the key molecules involved in this process may interfere with EMT process in the diffuse type of gastric cancer.

Immune expression of E-cadherin and α, ß and γ-Catenin adhesion molecules and prognosis for upper urinary tract urothelial carcinomas.

INTRODUCTION: Cell adhesion molecules (CAM) are required for maintaining a normal epithelial phenotype, and abnormalities in CAM expression have been related to cancer progression, including bladder urothelial carcinomas. There is only one study that correlates E-cadherin and Α-, Β- and y-catenin expression with prognosis of upper tract urothelial carcinomas. Our aim is to study the pattern of immune expression of these CAMs in urothelial carcinomas from the renal pelvis and ureter in patients who have been treated surgically. Our goal is to correlate these expression levels and characteristics with well-known prognostic parameters for disease-free survival. MATERIALS AND METHODS: We evaluated specimens from 20 patients with urothelial carcinomas of the renal pelvis and ureter who were treated with nephroureterectomy or ureterectomy between June 1997 and January 2007. CAM expression was evaluated by immunohistochemistry in a tissue microarray and correlated with histopathological characteristics and patient outcomes after a mean follow-up of 55 months. RESULTS: We observed a relationship between E-cadherin expression and disease recurrence. Disease recurrence occurred in 87.5% of patients with strong E-cadherin expression. Only 50.0% of patients with moderate expression and 0% of patients with weak or no expression of E-cadherin had disease recurrence (p = 0.014). There was also a difference in disease-free survival. Patients with strong E-cadherin expression had a mean disease-free survival rate of 49.1 months, compared to 83.9 months for patients with moderate expression (p = 0.011). Additionally, an absence of Α-catenin expression was associated with tumors that were larger than 3 cm (p = 0.003). CONCLUSIONS: We demonstrated for the first time that immune expression of E-cadherin is related to tumor recurrence and disease-free survival rates, and the absence of Α-catenin expression is related to tumor size in upper tract urothelial carcinomas.

Immune expression of E-cadherin and α, β and γ-Catenin adhesion molecules and prognosis for upper urinary tract urothelial carcinomas

INTRODUCTION: Cell adhesion molecules (CAM) are required for maintaining a normal epithelial phenotype, and abnormalities in CAM expression have been related to cancer progression, including bladder urothelial carcinomas. There is only one study that correlates E-cadherin and α-, β- and γ-catenin expression with prognosis of upper tract urothelial carcinomas. Our aim is to study the pattern of immune expression of these CAMs in urothelial carcinomas from the renal pelvis and ureter in patients who have been treated surgically. Our goal is to correlate these expression levels and characteristics with well-known prognostic parameters for disease-free survival. MATERIALS AND METHODS: We evaluated specimens from 20 patients with urothelial carcinomas of the renal pelvis and ureter who were treated with nephroureterectomy or ureterectomy between June 1997 and January 2007. CAM expression was evaluated by immunohistochemistry in a tissue microarray and correlated with histopathological characteristics and patient outcomes after a mean follow-up of 55 months. RESULTS: We observed a relationship between E-cadherin expression and disease recurrence. Disease recurrence occurred in 87.5% of patients with strong E-cadherin expression. Only 50.0% of patients with moderate expression and 0% of patients with weak or no expression of E-cadherin had disease recurrence (p = 0.014). There was also a difference in disease-free survival. Patients with strong E-cadherin expression had a mean disease-free survival rate of 49.1 months, compared to 83.9 months for patients with moderate expression (p = 0.011). Additionally, an absence of α-catenin expression was associated with tumors that were larger than 3 cm (p = 0.003). CONCLUSIONS: We demonstrated for the first time that immune expression of E-cadherin is related to tumor recurrence and disease-free survival rates, and the absence of α-catenin expression is related to tumor size in upper tract urothelial carcinomas.

Tissue-wide overexpression of alpha-T-catenin results in aberrant trophoblast invasion but does not cause embryonic mortality in mice.

Transcriptional activation of CTNNA3, encoding αT-catenin, by the Y153H mutated form of the human STOX1 transcription factor was proposed to be responsible for altered fetal trophoblast invasion into the maternal endometrium during placentation in pre-eclampsia. Here we have generated a mouse model to investigate the in vivo effects of ectopic αT-catenin expression on trophoblast invasion. Histological analysis was used to determine the invasive capacities of trophoblasts from transgenic embryos, as well as proliferation rates of spongiotrophoblasts in the junctional zone. Augmented expression of αT-catenin reduced the number of invading trophoblasts but did not cause embryonic mortality. The, αT-catenin positive cells could still invade into the decidual layer and migrated as deeply as wild-type trophoblasts. Furthermore, the junctional zone is enlarged in placentas of mice overexpressing αT-catenin due to hyperproliferation of the residing spongiotrophoblasts, suggesting a pivotal role of αT-catenin levels in the control of the proliferative versus invasive state of trophoblasts during placentation. Our study provides, for the first time, in vivo data on the effects of increased levels of αT-catenin in the placenta.

Utility of multispectral imaging in automated quantitative scoring of immunohistochemistry.

BACKGROUND: Automated scanning devices and image analysis software provide a means to overcome the limitations of manual semiquantitative scoring of immunohistochemistry. Common drawbacks to automated imaging systems include an inability to classify tissue type and an inability to segregate cytoplasmic and nuclear staining. METHODS: Immunohistochemistry for the membranous marker α-catenin, the cytoplasmic marker stathmin and the nuclear marker Ki-67 was performed on tissue microarrays (TMA) of archival formalin-fixed paraffin-embedded tissue comprising 471 (α-catenin and stathmin) and 511 (Ki-67) cases of prostate adenocarcinoma. These TMA were quantitatively analysed using two commercially available automated image analysers, the Ariol SL-50 system and the Nuance system from CRi. Both systems use brightfield microscopy for automated, unbiased and standardised quantification of immunohistochemistry, while the Nuance system has spectral deconvolution capabilities. RESULTS: Overall concordance between scores from both systems was excellent (r=0.90; 0.83-0.95). The software associated with the multispectral imager allowed accurate automated classification of tissue type into epithelial glandular structures and stroma, and a single-step segmentation of staining into cytoplasmic or nuclear compartments allowing independent evaluation of these areas. The Nuance system, however, was not able to distinguish reliably between tumour and non-tumour tissue. In addition, variance in the labour and time required for analysis between the two systems was also noted. CONCLUSION: Despite limitations, this study suggests some beneficial role for the use of a multispectral imaging system in automated analysis of immunohistochemistry.

Cadherin-catenin complex dissociation in lobular neoplasia of the breast.

E-cadherin (E-CD) inactivation with loss of E-CD-mediated cell adhesion is the hallmark of lesions of the lobular phenotype. E-CD is typically absent by immunohistochemistry in both lobular carcinoma in situ (LCIS) and invasive lobular lesions, suggesting it occurs early in the neoplastic process. In laboratory models, downstream post-transcriptional modifiers such as TWIST and SNAIL contribute to the dissociation of the intracellular component of the cadherin-catenin complex (CCC), resulting in tumor progression and invasion. We hypothesized that complete CCC dissociation may play a role in lobular neoplasia progression. Here we explore the relationship between loss of E-CD and dissociation of the CCC in pure LCIS and LCIS associated with invasive cancer. Fresh-frozen tissues were obtained from 36 patients undergoing mastectomy for pure LCIS (n = 11), LCIS with ILC (n = 18) or LCIS with IDC (n = 7). Individual lesions were subject to laser-capture microdissection and gene-expression analysis (Affymetrix HG-U133A 2.0). Immunohistochemistry for ER,PR,HER2, E-CD,N-CD,α-,ß-, and phosphoß-catenin, TWIST, and SNAIL were evaluated in normal, in situ, and invasive components from matched formalin-fixed paraffin-embedded samples (n = 36). CCC-dissociation was defined as negative membranous E-CD, α- and ß-catenin expression. E-CD was negative in all LCIS and ILC lesions, and positive in all normal and IDC lesions. Membranous α and ß-catenin expressions decreased with the transition from LCIS to ILC (pure LCIS 82%; LCIS w/ILC 28%; ILC 0%), while TWIST expression increased (pure LCIS low; LCIS w/ILC moderate; ILC high). Gene expression paralleled IHC-staining patterns with a stepwise downregulation of E-CD, α and ß-catenins from normal to LCIS to invasive lesions, and increasing expression of TWIST from normal to LCIS to ILC. Loss of E-CD expression is an early event in lobular neoplasia. Decreasing membranous catenin expression in tandem with increasing levels of TWIST across the spectrum of lobular lesions suggests that CCC dissociation is a progressive process.

A novel kind of tumor type-characteristic junction: plakophilin-2 as a major protein of adherens junctions in cardiac myxomata.

Using novel antibodies of high avidity to--and specificity for--the constitutive desmosomal plaque protein, plakophilin-2 (Pkp2), in a systematic study of the molecular composition of junctions connecting the cells of soft tissue tumors, we have discovered with immunocytochemical, biochemical and electron microscopical methods, a novel type of adherens junctions in all 32 cardiac myxomata examined. These junctions contain cadherin-11 as their major transmembrane glycoprotein, which we could repeatedly show in colocalization with N-cadherin, anchored in a cytoplasmic plaque formed by α- and ß-catenin, together with the further armadillo-type proteins plakoglobin, p120, p0071 and ARVCF. Surprisingly, all adherens junctions of these tumors contained, in addition, another major armadillo protein Pkp2, hitherto known as an obligatory and characteristic constituent of desmosomes in epithelium-derived tumors. We have not detected Pkp2 in a series of noncardiac myxomata studied in parallel. Therefore, we conclude that this acquisition of Pkp2, which we have recently also observed in some mesenchymally derived cells growing in culture, can also occur in tumorigenic transformations in situ. We propose to examine the marker value of Pkp2 in clinical diagnoses of cardiac myxomata and to develop Pkp2-targeted therapeutic reagents.

The survival effect of E-cadherin and catenins in colorectal carcinomas.

AIM: The E-cadherin/catenin complex plays an important role in epithelial tissue architecture. Decreased expression of cell adhesion molecules (E-cadherin, α-, ß- and γ-catenin) have been reported to correlate with invasive behaviour. The aim of this study was to investigate the relation between the expression of adhesion molecules and clinicopathological characteristics and survival in colorectal carcinoma. METHOD: The expression of adhesion molecules were studied by immunohistochemistry in 138 colorectal carcinomas. RESULTS: The mean age of the patients was 65 years (range: 21-89 years). In primary carcinomas, a reduction in membranous expression of E-cadherin, α-catenin, ß-catenin, γ-catenin was demonstrated (70%, 68%, 73%, 77%, respectively). Nuclear expression of ß-catenin was found in eight (5%) patients. Decreased membranous ß- and γ-catenin expression significantly correlated with tumour differentiation (P = 0.013, P = 0.03, respectively). There was a significant association between advanced stage of the tumour and decreased membranous α-catenin expression (P = 0.012). Decreased E-cadherin and ß-catenin membranous expression correlated with short survival following curative resection of the primary tumour (P = 0.04, P = 0.03, respectively). CONCLUSION: The decreased membranous expression of E-cadherin and ß-catenin and increased cytoplasmic expression of ß-catenin might be used as a prognostic marker to monitor patients with colorectal cancer.

Loss of Coxsackie and adenovirus receptor downregulates alpha-catenin expression.

BACKGROUND: The Coxsackie and adenovirus receptor (CAR) has been shown to inhibit cancer cell proliferation, migration, and invasion. The underlying mechanisms, however, are poorly understood. METHODS: The differential gene expression in the human colon cancer cell line DLD1 on RNAi-mediated functional CAR knockdown was analysed using oligo-array technology. Expression of alpha-catenin was determined by quantitative RT-PCR and western blotting. Proliferation, migration, and invasion after CAR knockdown were assessed by in vitro assays, and cell morphology in a three-dimensional context was evaluated using matrigel. RESULTS: Oligo-array technology identified alpha-catenin as the strongest downregulated gene after CAR knockdown. Western blotting and quantitative RT-PCR confirmed a reduced alpha-catenin expression after CAR knockdown in DLD1 cells and in the rat intestinal cell line IEC-6. Functionally, both cell lines showed a marked increase in proliferation, migration, and invasion on CAR knockdown. In matrigel, both cell lines formed amorphous cell clusters in contrast to well-organised three-dimensional structures of CAR-expressing vector controls. Ectopic 're'-expression of alpha-catenin in DLD1 and IEC-6 CAR knockdown cells reversed these functional and morphological effects. CONCLUSION: These data suggest that an interaction of CAR and alpha-catenin mediates the impact of CAR on cell proliferation, migration, invasion, and morphology.

Adhesion molecules and p16 expression in endocervical adenocarcinoma.

An immunohistochemical (IHC) study has been conducted on 34 cases of untreated endocervical adenocarcinomas collected among three institutions (Ospedale S. Andrea, Rome; Istituto Nazionale Tumori "Fondazione G. Pascale", Naples; and Clinica Malzoni, Avellino). The E-cadherin and alpha- and beta-catenin complex status has been investigated along with p16INK4a in all studied cases with the aim to study whether the pattern of expression of the cadherin-catenin complex could be causally related to the expression of P16INK4a protein. Results were evaluated for statistical significance by a non-parametric test (Kruskal-Wallis). Endocervical adenocarcinomas as a group were uniformly expressing p16INK4a except for two cases, and all lesions displayed downregulation of the cadherin-catenin complex, without demonstrating statistically significant differences among the different histotypes. The lack of nuclear accumulation of beta-catenin found in this group of lesions probably implies that no alteration of the beta-catenin/Wnt metabolic pathway is present in endocervical adenocarcinoma, as opposed to what is found in the literature for squamous carcinoma of the cervix. The diffuse expression of p16INK4a protein in this group of neoplasms stresses the important role of high-risk human papillomavirus infection in neoplastic causation possibly via the viral E7-mediated inactivation of pRB tumor-suppressor protein and also underlines the useful role of p16INK4a immunostaining in the diagnostic algorithm of endocervical adenocarcinomas. In consideration of these findings, investigation of downstream beta-catenin genes c-myc and cyclin D1 is sought as possibly contributive in the molecular pathogenesis of endocervical adenocarcinoma.

Expression of S100A4, E-cadherin, alpha- and beta-catenin in gastric adenocarcinoma.

BACKGROUND/AIMS: This investigation aimed to elucidate the expression patterns of S100A4 and adhesion molecules in gastric carcinoma and to estimate their correlation with clinicopathologic parameters. METHODOLOGY: The expression of S100A4, E-cadherin, alpha- and beta-catenin was studied in 251 gastric carcinoma specimens through immunohistochemical staining. RESULTS: The positive expression of S100A4 was significantly associated with advanced gastric cancer, higher pTNM stage, and poorer survival rates, especially when present in nuclear staining. The reduced expression of adhesion molecules was significantly associated with diffuse type of gastric cancer. The reduced expression of beta-catenin was significantly associated with lymph node metastasis, especially in early gastric cancer. The coexpression status of S100A4-positive and reduced beta-catenin was significantly associated with larger tumor size, advanced tumor depth, and higher pTNM stage. CONCLUSIONS: S100A4 and adhesion molecule expression may be a useful prognostic marker for individual gastric cancer patients.

Up-regulation of alpha-catenin is associated with increased lymph node involvement in colorectal cancer.

AIM: To investigate the changing pattern of alpha-catenin expression and its relationship to clinical and pathological features of colorectal cancer (CRC) patients. METHODS: Archival tumor samples were analyzed using immunohistochemistry (IHC) for alpha-catenin in 91 patients with advanced CRC. RESULTS: The values of alpha-catenin membrane index (MI) and cytoplasmic index (CI) were significantly related to the depth of tumor invasion (P = 0.027, P = 0.020, respectively), high indices being associated with increased depth of the primary tumor invasion (T3 and T4). Similarly, patients with high alpha-catenin expression had a significantly increased risk of lymph node metastasis (32/39 vs 37/52 for MI and 37/45 vs 32/46 for CI) (P = 0.001, P = 0.0001, respectively, for LNN status). An altered expression (i.e., cytoplasmic pattern) was also related (P = 0.047) to the response to chemotherapy; patients with low CI were more responsive (CR: 7/46) than patients with high CI values (CR: 0/45). There was a marginal effect on survival in patients time with metastases (SWM) (P = 0.087); patients with low CI showing slightly longer SWM, but no such effect on disease free survival (DFS) or disease specific survival (DSS). As to co-expression with another member of the adhesion complex (beta-catenin), high alpha-catenin/beta-catenin MI index was of marginal significance in predicting longer DSS (P = 0.063, log-rank). CONCLUSION: The results implicate that high alpha-catenin expression is intimately involved in the key regulatory mechanisms leading to invasive phenotype, lymph node metastases, and progressive disease in CRC.

Expression of motility-related protein MRP1/CD9, N-cadherin, E-cadherin, alpha-catenin and beta-catenin in retinoblastoma.

In our earlier study we showed that invasive retinoblastoma (RB) had down regulated tetraspanin protein KAI1/CD82, a family of cell surface glycoprotein. KAI1 may link to the cell surface molecules, such as integrins, E-cadherin, and other TM4SF members, and loss of KAI1 function may have a significant role in the progression of retinoblastoma. We also showed that epithelial cell adhesion molecule (EpCAM) is overexpressed in invasive RB. EpCAM expression decreases adhesion mediated by cadherins. Thus, we were further interested in studying the role of other adhesion molecules like cadherins and catenins in RB. We studied the expression of Motility-Related Protein 1 (MRP-1)/CD9, E-cadherin, N-cadherin, alpha-catenin and beta-catenin in RB and correlated clinicopathologically in 62 archival paraffin-embedded tumors by immunohistochemistry. There were 29 tumors with no invasion of choroids/optic nerve and 33 tumors with invasion of choroid/optic nerve/orbit. Western blotting was performed on 20 tumors using the same antibodies. We observed higher expression of CD9 (P<0.001), E-cadherin (P<0.001) and alpha-catenin (P<0.001) in the non-invasive RB and higher expression of N-cadherin (P<0.001) in invasive RB. The expression of beta-catenin was not significantly different between two groups of tumors. In Western blotting, we were able to see CD9 and E-cadherin expression in a minority of tumors while N-cadherin, alpha-catenin and beta-catenin were expressed with differing intensities in a majority of tumors. Thus, invasive tumors expressed increased N-cadherin, alpha-catenin and decreased E-cadherin and CD9. Thus, it appears that loss of E-cadherin and gain of N-cadherin expression are features of invasiveness. Further functional studies are required to evaluate the role of beta-catenin in RB.

Ultrastructural localization of alpha E-catenin in the rat sciatic nerve.

Alpha E-catenin is included in the same category as alpha N-catenin, and both of them have been identified as subtypes of alpha-catenin. A previous study issued from our laboratory demonstrated that alpha N-catenin is localized in the axoplasm of unmyelinated peripheral nerves, whereas the localization of alpha E-catenin in the peripheral nervous system has not yet been reported. The present study was focused on the distribution of alpha E-catenin in the rat sciatic nerve. By electron microscopy using immunocytochemical methods, alpha E-catenin immunoreactivities were generally detected in the Schwann cell cytoplasm of unmyelinated nerve and the outer loop of myelinated nerve. Those findings suggest that alpha E-catenin may be associated with Schwann cell-Schwann cell or axon-Schwann cell contacts.

Aberrant retinal tight junction and adherens junction protein expression in an animal model of autosomal dominant Retinitis pigmentosa: the Rho(-/-) mouse.

Retinitis pigmentosa (RP) comprises a heterogeneous group of inherited diseases that are characterised by primary degeneration of rod photoreceptors and secondary degeneration of cone photoreceptors in the retina. Additional pathological changes include vascular changes and invasion of the inner retina by retinal pigment epithelial (RPE) cells. RP represents a major cause of progressive retinal disease worldwide. Using a mouse model of autosomal dominant Retinitis pigmentosa (adRP) with retinopathy induced by targeted disruption of the rhodopsin gene Rho(-/-), we have analysed the levels of expression of a range of tight and adherens junction associated proteins, in order to further elucidate the pathogenic mechanisms occurring at an early stage of this condition. Using western blot analysis and indirect immunostaining of retinal cryosections from 6-week-old mice from a C-129 background we have determined changes, if any, in the levels of expression and localisation of a series of tight and adherens junction associated proteins, including Zonula Occludens-1 (ZO-1), occludin, N-Cadherin, p120-Catenin, alpha-Catenin, gamma-Catenin, beta-Catenin, and E-Cadherin. We have found an up-regulation of the tight junction and adherens junction associated protein Zonula Occludens-1 (ZO-1) in the neural retina of 6-week-old Rho(-/-) knockout mice compared with 6-week-old Wild-Type (WT) mice. Following immunohistochemistry, however, it appears, that ZO-1, beta-Catenin and p120-Catenin expression at the Outer Limiting Membrane (OLM) of the Rho(-/-) retina is compromised, in part, compared to WT animals of the same age. We hypothesise that these retinal changes following photoreceptor cell death may contribute to the pathogenesis of adRP. Our findings of changes in the levels of expression of ZO-1 and associated adherens junction proteins beta-Catenin and p120-Catenin at the OLM in 6-week-old Rho(-/-) mice provide evidence for tight junction and adherens junction associated protein modifications in an animal model of autosomal dominant RP (adRP).

Expression of E-cadherin, cadherin-11, alpha-, beta- and gamma-catenins in nephroblastomas: relationship with clinicopathological parameters, prognostic factors and outcome.

AIM: This study was undertaken to determine the expression of cell adhesion molecules E-cadherin, cadherin-11, and alpha-, beta- and gamma-catenins in nephroblastomas and to correlate this expression with pathological features and known prognostic factors. METHODS: Immunohistochemistry was performed on 140 cases of nephroblastoma following heat-induced epitope retrieval and using the streptavidin-biotin technique. RESULTS: E-cadherin was expressed in 75 cases (54%), cadherin-11 in 128 cases (91%), alpha-catenin in 93 cases (66%), beta-catenin in 133 cases (95%) and gamma-catenin in 22 cases (16%). Nuclear localisation of beta-catenin was not demonstrated. There was a statistically significant relationship between the administration of preoperative chemotherapy and the expression of E-cadherin, alpha- and gamma-catenin, respectively. These proteins were more frequently expressed in tumours treated with preoperative chemotherapy. Those tumours that expressed all four proteins (E-cadherin, alpha-, beta- and gamma-catenin) showed a statistically significant association with the administration of preoperative chemotherapy, in contrast to tumours that did not express all four proteins. CONCLUSION: Nephroblastomas show a heterogeneous distribution of staining for E-cadherin, cadherin-11, alpha-, beta- and gamma-catenins. Tumours treated with preoperative chemotherapy are more likely to express these molecules. The expression status of E-cadherin, cadherin-11 and the catenins in this cohort does not appear to be of prognostic value.

Links between alpha-catenin, NF-kappaB, and squamous cell carcinoma in skin.

Cancers display a diverse set of cellular defects, which are thought to be elicited by multiple genetic mutations. In this study, we show that when a single adherens junction protein, alpha-catenin, is removed by conditional targeting, the entire skin epidermis systematically transforms to a hyperproliferative, invasive tissue replete with inflammation. Transcriptional profiling and biochemical analyses reveal that alpha-catenin ablation is accompanied by activation of NF-kappaB and its proinflammatory target genes, along with genes involved in proliferation, wound healing, angiogenesis, and metastasis. Many of these alterations occur in vitro and in the embryo, and thus seem at least partly to be intrinsic to the loss of alpha-catenin. We show that reductions in alpha-catenin, activation of NF-kappaB, and inflammation are common features of human squamous cell carcinomas of the skin.

Ultrastructural and immunohistochemical analysis of rat uroepithelial cell junctions after partial bladder outlet obstruction and selective COX-2 inhibitor treatment.

The present study was undertaken to evaluate alterations in uroepithelial cell junctional complexes in partial bladder outlet obstruction (PBOO) of rat bladders using ultrastructural morphometry and immunohistochemistry, and to determine whether selective COX-2 inhibitors have any effects on these structures. A total of 18 male rats were separated into three groups of six rats each: (1) sham-operated animals served as controls; (2) a PBOO group, without further treatment (3) and a group that immediately after PBOO, received treatment for 4 weeks with oral Celecoxib, a selective COX-2 inhibitor. Uroepithelial cell junctions were evaluated using transmission electron microscopy combined with morphometry. Results were also assessed by E-cadherin and alpha-catenin immunohistochemistry. Morphometrical analysis of ultrastructural evaluations revealed that 4 weeks of PBOO caused a significant reduction in the electron density of zonula adherens and zonula occludens junctional complexes. Moreover, some desmosomes located between the deeper cells of the uroepithelium showed signs of disintegration. Selective COX-2 inhibitor treatment during 4 weeks of PBOO showed protective effects on adherens and occludens junctions, as well as on desmosomes. Immunohistochemical analysis of E-cadherin confirmed that the decreased E-cadherin immunolabelling in 4 weeks of PBOO was prevented by selective COX-2 inhibitor treatment. Based on ultrastructural morphometrical analysis, we conclude that PBOO alone and in combination with selective COX-2 inhibitors can have considerable effects on uroepithelial cellular junctions. Our findings provide a novel area of investigation regarding the selective use of COX-2 inhibitors following PBOO.