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.     

滑膜肉瘤中E-、N-cadherin和β-catenin的表达及意义

目的探讨上皮间叶转化(EMT)相关蛋白E-、N-cadherin和β-catenin在滑膜肉瘤中的表达及意义。方法收集滑膜肉瘤34例,包括双相型24例和单相纤维型10例,应用免疫组化EnVision两步法检测E-、N-cadherin和β-catenin的蛋白表达水平。结果 (1)E-、N-cadherin和β-catenin在34例滑膜肉瘤中的阳性率分别为52.9%、76.5%、97.1%。E-cadherin在双相型滑膜肉瘤中的阳性率(70.8%)高于单相纤维型(10%)(P<0.05);N-cadherin、β-catenin在双相型和单相纤维型滑膜肉瘤中的阳性率分别为70.8%(17/24)和90%(9/10)、95.8%(23/24)和100%(24/24),差异均无显著性(P>0.05)。(2)在24例双相型梭形细胞成分中E-、N-cadherin和β-catenin的阳性率分别为12.5%(3/24)、50%(12/24)和62.5%(15/24);在10例单相纤维型滑膜肉瘤梭形细胞成分中的阳性率分别为10%(1/10)、80%(8/10)和100%(10/10)。β-catenin在单相纤维型滑膜肉瘤的梭形细胞的表达率高于双相型中的梭形细胞(P<0.05)。(3)在24例双相型滑膜肉瘤中,E-、N-cadherin和β-catenin在上皮样细胞中的阳性率分别为70.8%(17/24)、83.3%(20/24)和95.8%(23/24);在梭形细胞成分中的阳性率分别为12.5%(3/24)、50%(12/24)和62.5%(15/24)。E-、N-cadherin和β-catenin在上皮样细胞中的表达均高于梭形细胞(P<0.05)。(4)在双相型滑膜肉瘤中E-cadherin和N-cadherin、E-cadherin和β-catenin均同时表达的比例较高,在单相纤维型中E-cadherin不表达而N-cadherin、β-catenin表达的比例较高。(5)滑膜肉瘤中E-、N-cadherin和β-catenin的表达与患者年龄、肿瘤大小、组织学分级和临床TNM分期之间差异均无显著性(P>0.05)。结论 EMT相关蛋白E-、N-cadherin和β-catenin均可能参与滑膜肉瘤的组织形态分化,N-cadherin和β-catenin影响双相型和单相纤维型滑膜肉瘤中E-cadherin的表达途径不同,滑膜肉瘤组织中可能存在间叶上皮转化(MET)现象。对其深入研究将有助于阐明滑膜肉瘤浸润和转移的分子机制。     

沉默RhoA基因对腺样囊性癌细胞迁移和侵袭的影响

目的 探讨RhoA基因对唾液腺腺样囊性癌(salivary adenoid cystic carcinoma,SACC)细胞的迁移和侵袭能力的影响.方法 将液氮冻存的20例SACC及正常癌旁组织研磨匀浆,分别提取总RNA和总蛋白检测RhoA的表达情况.同时构建RhoA-siRNA转染2个细胞株SACC-LM和SACC-...     

上皮间质转化及CD146和N-cadherin在判定肺腺癌EGFR-TKI获得性耐药中的作用

目的 探讨上皮间质转化及CD146、N-cadherin判定肺腺癌表皮生长因子受体-酪氨酸激酶抑制剂（epidermal growth factor receptor-tyrosine kinase inhibitor,EGFR-TKI）耐药的价值。方法 肺腺癌患者10例均应用EGFR-TKI治疗,采用免疫组织化学法检测治疗前、后肺腺癌标本E-cadherin、vimentin、CD146及N-cadherin蛋白表达情况,采用图像分析系统检测各指标吸光度值。结果 EGFR-TKI治疗后肺腺癌组织E-cadherin蛋白表达水平（0.180±0.011）低于治疗前（0.231±0.012）,vimentin、N-cadherin与CD146蛋白表达水平（0.231±0.012,0.214±0.013,0.321±0.022）高于治疗前（0.165±0.012,0.174±0.013,0.161±0.022）（P〈0.05）。结论 EGFR-TKI耐药后肺腺癌产生上皮间质转化并使CD146、N-cadherin表达上调,E-cadherin、vimentin、CD146、N-cadherin可作为诊断肺腺癌EGFR-TKI耐药的分子标志物。     

多种转移潜能不同的人前列腺癌细胞“上皮细胞间质转化态”特性鉴定及其意义

目的:对多种转移潜能不同的人前列腺癌细胞“上皮细胞间质转化态”(EMT)特性进行鉴定,并从粘附因素和细胞骨架蛋白角度分析其骨转移潜能获得的分子机制。方法:用W estern印迹法鉴定LNCaP及其亚细胞系C4、C4-2和ArCaP亚细胞系IF11、IA8,以及PC-3、Du145等细胞中上皮型钙粘素(E-cadherin)、神经型钙粘素(N-cadherin)和波形纤维蛋白(V im entin)的表达差异情况,并分析其在前列腺癌转移过程中的作用。结果:E-cad-herin在PC-3、LNCaP、C4、C4-2中表达较高,但在Du145、IF11、IA8中表达极低;而V im entin的表达情况恰恰与E-cadherin相反;N-cadherin在IF11、IA8细胞中呈现显著的高表达状态。结论:转移潜能不同的人前列腺癌细胞株之间存在EMT表型的表达差异,其中PC-3、LNCaP、C4、C4-2是未发生EMT改变的细胞,Du145、IF11、IA8却是EMT化的细胞。EMT表型差异蛋白在解释前列腺癌转移机制方面占据着重要地位。