N-cadherin expression in adrenal tumors: upregulation in malignant pheochromocytoma and downregulation in adrenocortical carcinoma

Cell adhesion molecules (CAMs) are important regulators of tumor growth. The aim of the present study was to evaluate the expression pattern of CAMs in adrenal tumors regarding origin (cortex vs medulla) and biologic behavior (benign vs malignant). Eighty-seven adrenal tumors were investigated by immunocytochemistry (ICC) using monoclonal antibodies against N-cadherin (NCAD), E-cadherin (ECAD), neural cell adhesion molecule (NCAM), and CD44. Western blotting was performed on 30 tumors using the same antibodies. Markers for proliferation (Ki-67) and catecholamine synthesis (tyrosine hydroxylase) were also analyzed in tumors by ICC. NCAD was expressed in 12/27 benign pheochromocytomas (BPCs) (12 familial cases), 8/8 malignant pheochromocytomas (MPCs), 28/30 adrenocortical adenomas, and 9/22 adrenocortical carcinomas. ECAD was expressed in 0/27 BPCs, 0/8 MPCs, 0/30 adrenocortical adenomas, and 2/22 adrenocortical carcinomas. NCAM was expressed in 26/27 BPCs, 7/8 MPCs, 21/30 adrenocrotical adenomas, and 17/22 adrenocortical carcinomas. CD44 was expressed in 23/27 BPCs, 6/8 MPCs, 7/30 adrenocortical adenomas, and 4/22 adrenocortical carcinomas. Both cortical and medullary adrenal tumors expressed NCAD, NCAM, and CD44 but were devoid of ECAD. The expression of CD44 and NCAM did not correlate with the malignant potential of tumors. NCAD was upregulated in MPCs, but downregulated in adrenocortical carcinoma. Thus, NCAD appears to be involved in the development of both cortical and medullary adrenal tumors.     

Genomic structure and eight novel exonic polymorphisms of the human N-cadherin gene

 Analysis of the detailed genomic structure of human N-cadherin revealed that the 16-exon gene is more than 72 kb in length and that it consists of a mosaic of exons. Five repeated cadherin domains, a transmembrane domain, and a cytoplasmic domain are encoded by exons 4 to 13, 13 and 14, and 14 to 16, respectively. A search for molecular variants in the entire coding region in 96 Japanese individuals resulted in the identification of eight sequence polymorphisms including three CCT- or GCC-type trinucleotide repeat polymorphisms adjacent to the initiation codon and five other novel single-nucleoticle polymorphisms (SNPs) in the coding region. Three of the five SNPs accompanied an amino acid substitution: Ala118Thr, Ala826Thr, and Asn845Ser. Knowlege of the fine gene structure and eight novel polymorphisms will be useful for the genetic study of the role of N-cadherin in diseases involving cell adhesion in the brain and in cardiomyocytes. Received: January 23, 2002 / Accepted: March 12, 2002     

Mycobacteria Induces Pleural Mesothelial Permeability by Down-Regulating β-Catenin Expression

Patients with pulmonary tuberculosis develop pleural effusions with a high protein content. Pleural mesothelial adherens junctions promote mesothelial cell-cell adhesion and contribute to pleural integrity. In the present study we have investigated the effect of mycobacterium (BCG) on mesothelial cell adherens junction proteins and pleural permeability. BCG enhanced pleural mesothelial cell (PMC) release of vascular endothelial growth factor (VEGF), and decreased electrical resistance across the PMC monolayer. Neutralizing antibodies to VEGF significantly restored the drop in PMC electrical resistance caused by BCG. BCG infection down regulated -catenin (adherens junction protein) expression and caused increased permeability across confluent mesothelial monolayer. Our results suggest that in TB pleurisy, mycobacteria cause VEGF release from mesothelial cells and leads to protein exudation by altering mesothelial adherens junction proteins.     

Snail、E-cadherin 和N-cadherin 在非小细胞肺癌组织的表达及相关性研究

目的：探讨上皮型钙黏附素（E-cadherin）、神经型钙黏附素（N-cadherin）及Snail在非小细胞肺癌（NSCLC）中的表达及其临床意义。方法采用实时荧光定量PCR测定Snail、E-cadherin和N-cadherin基因在10对非小细胞肺癌及其癌旁正常肺组织中的表达情况,同时采用免疫组化法检测105例NSCLC以及41例癌旁组织中Snail、E-cadherin和N-cadherin蛋白的表达。结果与癌旁正常肺组织相比较,非小细胞肺癌组织中E-cadherin的表达显著减少,N-cadherin和Snail表达明显增加（P〈0.05）。NSCLC组织中,Snail的表达与N-cadherin的表达呈明显的正相关（P〈0.05,r=0.21）,与E-cadherin的表达呈显著负相关（P〈0.05,r=-0.39）,而N-cadherinl的表达与E-cadherin的表达也呈明显负相关（P〈0.05,r=-0.53）。结论非小细胞肺癌组织中, Snail、N-cadherin呈显著高表达,而E-cadherin呈显著低表达,三者可能通过相互作用共同参与NSCLC的发生和发展。     

舌鳞状细胞癌中Survivin的表达及与上皮细胞-间质转化的关系

目的探讨Survivin在舌鳞状细胞癌(tongue squamous cell carcinoma,TSCC)中的表达及其与上皮细胞-间质转化(epithelial-mesenchymal transition,EMT)的关系。方法采用免疫组化EnVision法检测63例TSCC及相应癌旁正常组织中Survivin和EMT标志物的表达,分析Survivin表达与TSCC临床病理特征的关系及其与EMT标志物的相关性。应用Western blot法检测8例TSCC新鲜组织中Survivin、E-cadherin和N-cadherin的表达。结果TSCC组织中Survivin阳性率为81.0%,明显高于相应癌旁正常组织中(15.9%);Survivin表达与TSCC临床分期、病理分级及淋巴结转移有明显相关性。E-cadherin和N-cadherin在TSCC组织中阳性率分别为42.9%和69.8%;Survivin与E-cadherin的表达呈负相关,与N-cadherin表达呈正相关。Western blot实验结果也证实,Survivin和N-cadherin在TSCC组织中呈高表达,而E-cadherin呈低表达。结论Survivin表达与TSCC组织EMT标志物有关,Survivin可能通过诱导TSCC细胞发生EMT,从而促进TSCC的侵袭和转移。     

Involvement of N-cadherin/β-catenin interaction in the micro/nanotopography induced indirect mechanotransduction

Topographical modification at micro- and nanoscale is widely applied to enhance the tissue integration properties of biomaterials, but the underlying molecular mechanism is poorly understood. The biomaterial topography modulates cell functions via mechanotransduction of direct and indirect. We propose that N-cadherin may play a role in the topographically induced indirect mechanotransduction by regulating the β-catenin signaling. For confirmation, the cell functions, N-cadherin expression and β-catenin signaling activation of osteoblasts on titanium (Ti) surfaces with micro- or/and nanotopography are systemically compared with naive and N-cadherin down-regulating MC3T3-E1 cells. We find that the N-cadherin expression is reversely related to the intracellular β-catenin signaling and the N-cadherin/β-catenin signaling is modulated differentially by the micro- and nanotopography. The nanotopography significantly up-regulates the N-cadherin expression leading to lower β-catenin signaling activity and consequently depressed differentiation, whereas the microtopography down-regulates the N-cadherin expression resulting in enhanced β-catenin signaling and thus osteoblast differentiation. Artificial down-regulation of the N-cadherin expression can significantly up-regulate the β-catenin signaling and consequently enhance the osteoblast differentiation on all the Ti surfaces. The study for the first time clarifies the involvement of the N-cadherin/β-catenin interaction in the micro/nanotopography induced indirect mechanotransduction and provides a potentially new approach for biomaterial modification and biofunctionalization by down-regulating the cell N-cadherin expression to achieve improved clinical performance.     

Expression of TGF-β1, Snail, E-cadherin and N-cadherin in Gastric Cancer and Its Significance

OBJECTIVE To investigate the expression of TGF-β1,Snail,E-cad-herin and N-cadherin in gastric cancer(GC),and to examine its relationship to malignant features of the tumors. METHODS The expression of TGF-β1,Snail,E-cadherin and N-cadherin proteins was detected in GC and adjacent tissues by immunohistochemical staining,and compared with the clinico-pathological data. RESULTS Positive rates of expression for TGF-β1,Snail,E-cadherin and N-cadherin were 63.5%,83.3%,37.5%and 44.8%in GC,and 28.8%, 41.3%,100%,11.3%in adjacent tissues,respectively.The expression of all four proteins showed a significant difference between the GCs and adjacent tissues(P<0.05).The positive rate of TGF-β1,Snail and N-cadherin,or the negative rate of E-cadherin expression was significantly related to the differentiated degree,histological type,invasion and metastasis of GC.In addition,the expression of N-cadherin was positively related to that of TGF-β1, but negatively related to that of E-cadherin.There was negative correlation between expression of E-cadherin and TGF-β1 and Snail in GC(P<0.05). CONCLUSION The over-expression of TGF-β1 and Snail and decreased expression of E-cadherin and the abnormal expression of N-cad-herin were involved in the process of invasion and metastasis of GC.The data showed that E-cadherin might switch to N-cadherin.TGF-β1 and Snail might play a fundamental role in the process.     

肺岩宁方对EMT间质细胞标志因子Vimentin、Fibronectin和N—cadherin表达的影响

目的：研究标志EMT过程发生的间质细胞因子Vimentin、Fibronectin和N—cadherin在C57小鼠Lewis肺癌中的表达，以及肺岩宁方对其mRNA表达的影响。方法：采用Real—TimePCR观察C57小鼠Lewis肺癌右腋下移植瘤和远处转移灶发生的肺组织中Vimentin、Fibronectin和N—cadherinmRNA表达及肺岩宁方对它表达的影响。结果：对于各组移植肿瘤组织中，间质细胞标志因子Vimentin经肺岩宁方治疗后，与模型组相比无差异（P〉0．05）；而Fibronectin和N—cadherin的表达经肺岩宁方治疗后，与模型组相比明显降低（P〈0．01）；对于各组肺组织中，Vimentin、Fibronectin和N—cadherin在转移率发生最高的模型组，其表达明显高于正常肺组织中的表达（P〈0．01），而经过肺岩宁方治疗后，与模型组相比，Fibronectin和N—cadherin标志因子表达均显著性下降（P〈0．05），而Vimentin标志因子治疗前后无差异（P〉0．05）。结论：EMT有可能参与了肺癌转移的发生；肺岩宁方具有下调标志EMT过程发生的间质细胞因子Fibronectin和N—cadherin的作用。     

Side-to-side linking of myocardial cells in hypertrophic cardiomyopathy: whole heart microscopic observation with tangential sections

By cross-section or longitudinal section, it is difficult to investigate longitudinal features of myocardial cells in the whole heart. Here, introducing the use of tangential sections to obtain longitudinal aspect of myocardial cells in any part of myocardium, the authors evaluated myocardium in the left ventricle in 10 normal hearts and four hearts with hypertrophic cardiomyopathy (HCM). Tangential sections were obtained by peeling the superficial layer of myocardium. After peeling the whole surface, secondary deep layer was peeled. These procedures were repeated more than five times through the wall. Intercalated discs (ICD) were observed immunohistochemically with anti-N-cadherin and antidesmoplakin. In normal hearts, myocardial cells were cut longitudinally and ran parallel in tangential sections. They linked end-to-end with simple and regular ICD with average lengths of 120-130 microm and average sarcomere numbers of 56-65. In HCM hearts, many myocardial cells were cut almost longitudinally running approximately parallel in tangential sections. Myocardial cells frequently showed side-to-side linking characterized by skewed ICD, indistinct ICD counterparts, and longitudinally arranged ICD. Two young HCM hearts had circle-shaped ICD and vacuole-like structures highlighted by immunostaining for N-cadherin, which were actually extracellular structures comparable with irregular side-to-side linking. It is considered that side-to-side linking of myocardial cells is a characteristic microscopic feature in HCM rather than myocardial disarray.     

Studies on protocadherin-2 expression in the human fetal central nervous system

Protocadherin (Pcad) is a group of molecules obtained by polymerase chain reaction (PCR) utilizing the sequence that is well preserved in the extracellular domain of cadherin. Sano et al. analyzed Pcad (PC42,43) that had been cloned from rats, and found that it basically had homology to cadherin, but contained more than six cadherin repeats with a completely different intracellular domains (Sano et al. 1993). In the present study, of the Pcad (Pcad-1,2) cloned from a human cDNA library, as-yet-unspecified Pcad-2 was analyzed for expression in the human fetal central nervous system (CNS). Northern blot analysis of adult human tissue showed that Pcad-2 was expressed in the brain and the placenta, and that Pcad-2 mRNA was expressed in actively dividing neural tumor cell lines. Monoclonal antibodies against Pcad-2 were then made, and the CNS of fetuses were immunohistochemically stained. The expression was hardly visible at the 6th week of pregnancy, and began to become visible along the nerve fiber in the brain stem at the 8th week, and spread over the entire brain at the 11th week. At the 18th week, however, expression in the nerve fascicles, which had been visible by that time, was no longer visible or had decreased. These results suggest that Pcad-2 appears relatively early in the critical stage of development of the fetal CNS, and is involved in the induction, fasciculation, and extension of axons.