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Claudin Expression (claudin + expression)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Loss of claudin-1 expression in tumor-associated vessels correlates with acquisition of metastatic phenotype in melanocytic neoplasms

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 8 2005
Michael L. Cohn
Recent studies have suggested that some metastatic solid tumors lack claudin expression. It is unknown whether claudins play a role in cutaneous melanoma. Immunohistochemical studies were performed on tissue microarrays containing 19 benign melanocytic nevi (BN), 21 dysplastic nevi (DN), 23 primary malignant melanomas (MMs), and 31 metastatic melanomas (MMMs) using a polyclonal anti-claudin-1 antibody. Immunoreactivity in tumor cells and associated vessels was graded by intensity and by percentage of reactive cells. Normal epidermis served as internal control (3+ labeling). Cases with at least 2+ labeling in more than 25% of the cells were considered positive. Claudin-1 expression was present in 37% of BN, 24% of DN, 26% of MM, and 3.2% of MMM. Tumor-associated vessels showed the following results: 11 of 19 (58%) in BN, 14 of 21 (67%) in DN, 17 of 23 (74%) in MM, and 6 of 31 (19%) in MMM. A significant loss of expression was noted between MMM and all other lesions in tumor cells and associated vessels. There was no significant difference between BN, DN, and MM. Within primary melanomas, there was a significant correlation between expression of claudin in tumor cells and Clark level/Breslow thickness. Also significant was a decreased expression of claudin in tumor vessels of lesions with higher Breslow thickness or Clark level. These data suggest that loss of claudin-1 may play a significant role in the acquisition of metastatic phenotype in cutaneous melanoma. [source]

Cdx2 transcription factor regulates claudin-3 and claudin-4 expression during intestinal differentiation of gastric carcinoma

PATHOLOGY INTERNATIONAL, Issue 3 2008
Shinya Satake
According to the expression of gastric (claudin-18) and intestinal claudins (claudin-3 and claudin-4), the authors have previously proposed a new phenotypic classification of gastric carcinoma (GC): the gastric (G-CLDN), intestinal (I-CLDN) and unclassified claudin (U-CLDN) phenotypes. The aim of the present study was to examine the role of Cdx2, the caudal -related transcription factor, on the regulation of intestinal claudins expression in vitro and in vivo. It was confirmed on immunohistochemistry that non-neoplastic gastric mucosa with intestinal metaplasia (IM) expressed Cdx2 with increased levels of intestinal claudin expression. In addition, Cdx2 expression was detected in 28 (30%) of 94 GC at the invasive front. Interestingly, Cdx2 expression had a significant association with the I-CLDN phenotype (P < 0.001), which was almost identical to the established gastric and intestinal mucin-based GC classification. Furthermore, the transfection of a recombinant human CDX2 -expressing vector into TMK-1 (Cdx2-negative) GC cells specifically elevated the expression of claudin-3 and claudin-4 at the mRNA (CLDN3, 3.9-fold; CLDN4, 2.8-fold) and protein levels (claudin-3, 8.6-fold; claudin-4, 9.8-fold), whereas no induction of the other claudins was detected. These findings suggest that Cdx2 plays an important role in the regulation of intestinal claudin expression not only in gastric mucosa with IM but also GC. [source]

,-catenin expression and claudin expression pattern as prognostic factors of prostatic cancer progression

BJU INTERNATIONAL, Issue 5 2010
Attila M. Szász
OBJECTIVE To investigate the patterns of expression of the junctional proteins ,-catenin and claudins in different prognostic groups of patients with prostatic cancer, to determine their value as prognostic markers. PATIENTS AND METHODS We evaluated the samples of 30 patients who had a radical prostatectomy for organ-confined cancer (pT2N0M0), men with clinically advanced cancer, and a control group with benign prostatic hyperplasia. Using immunohistochemistry applied to tissue microarrays, each group was evaluated for claudin-1, -2, -3, -4, -5, -7, -8 and -10, and ,-catenin expression. RESULTS There were differences among the three groups in the expression of claudin-1 (P = 0.001), -2 (P = 0.014), -3 (P = 0.027), -4 (P = 0.001), -8 (P = 0.001) and ,-catenin (P = 0.002), regardless of Gleason score. By contrast, claudin-5, -7 and -10 patterns were not significantly different among the groups. Furthermore, claudin-1 (P = 0.014) and -4 (P = 0.004) could be used to distinguish between those patients who had metastases and those who did not. CONCLUSIONS The pattern of claudin expression could be a novel diagnostic marker in re-classifying adenocarcinomas, and an additional sensitive predictive factor for a clinically poor prognosis. Our results suggest that patients with organ-confined and advanced cancer are subsets with distinct claudin expression profiles, and that claudin-4 is related to cellular differentiation in prostate cancer, which is not only the receptor molecule for the Clostridium perfringens enterotoxin, and thus a theoretical future therapeutic target for prostate cancer, but also a marker of progression. [source]

Abrogation of IFN-, mediated epithelial barrier disruption by serine protease inhibition

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2005
L. E. M. Willemsen
Summary The intestinal barrier function is often impaired in a variety of diseases including chronic inflammatory bowel disease. Increased intestinal permeability during episodes of active disease correlates with destruction or rearrangement of the tight junction protein complex. IFN-, has been widely studied for its effect on barrier function and tight junction structures but its mode of action remains unclear. Since the claudin family of tight junction proteins is proposed to be involved in barrier maintenance we studied the effect of IFN-, on claudin expression in relation to epithelial barrier function. Cycloheximide and protease inhibitors were used to study mechanisms of IFN-, mediated barrier disruption. Intestinal epithelial cells were exposed to IFN-, and permeability was evaluated by horse radish peroxidase (HRP) and 4 kD FITC-dextran fluxes. Occludin and claudin-1, -2, -3, and -4 tight junction protein expression was determined by Western blotting. Occludin and claudin-2 protein expression was dramatically reduced after IFN-, exposure, which correlated with increased permeability for HRP and FITC-dextran. Interestingly, cleavage of claudin-2 was observed after incubation with IFN-,. Serine protease inhibitor AEBSF completely abrogated IFN-, mediated barrier disruption which was associated with preservation of claudin-2 expression. Moreover, IFN-, induced loss of barrier integrity was found to affect claudin-2 and occludin expression through different mechanisms. Since inhibition of serine protease activity abrogates IFN-, mediated barrier disruption this may be an important target for therapeutic intervention. [source]