Effects of RhoA on the adherens junction of murine ameloblasts / 北京大学学报(医学版)

OBJECTIVE@#To investigate the regulation mechanism of RhoA signaling pathway during the enamel formation by using the EGFP-RhoADominant Negative (EGFP-RhoADN) transgenic mice model, from the aspect of adherens junctions, and to provide a theory basis for mechanism of enamel development defects.@*METHODS@#The enamel thickness of mandibular first molars of EGFP-RhoADN transgenic mice and wild type (WT) mice were observed by scanning electronic microscopy at 20 kV, and the enamel thickness of the distal face of the central cusp was measured at 10 locations via analysis by ImageJ (Rasband, 1997-2009). The enamel organs from mandibular first molars from postnatal-4-day (P4) EGFP-RhoADN mice and wild type mice were isolated, and the total RNA and protein were extracted from the epithelium of the enamel organs. The expression level of the adherens junctions components in ameloblasts layer of the postnatal-4-day EGFP-RhoADN transgenic mice and wild type mice mandibular first molars were detected by real-time PCR and Western blot assay.@*RESULTS@#The EGFP-RhoADN transgenic mice had decreased enamel thickness in their bilateral mandibular first molars versus those of control group (n=20), and enamel thickness was (84.60±0.20) μm vs. (106.24±0.24) μm, P<0.05. The protein expressions of E-cadherin, α-E-catenin and pan-cadherin in ameloblasts layer of postnatal-4-day EGFP-RhoADN transgenic mice molars were down-regulated, and the protein level of β-catenin in ameloblasts layer of P4 EGFP-RhoADN transgenic mice molars was up-regulated. The mRNA level of E-cadherin in ameloblasts layer of P4 EGFP-RhoADN transgenic mice molars was down-regulated versus that of WT mice, and the gene expression of E-cadherin was 0.93±0.01 vs. 1.00±0.02, P<0.05. The mRNA level of β-catenin in ameloblasts layer of P4 EGFP-RhoADN transgenic mice molars was up-regulated versus that of WT mice, and the gene expression of β-catenin was 1.23±0.03 vs. 1.00±0.05, P<0.05.@*CONCLUSION@#In the mandibular first molars of EGFP-RhoADN transgenic mice, the enamel formation was disrupted and the adherens junctions of EGFP-RhoADN transgenic mice ameloblasts were implicated during amelogenesis. RhoA signaling pathway may play a critical role in enamel development by altering the adherens junctions in ameloblasts.

Luteolin Induces Apoptosis via Mitochondrial Pathway and Inhibits Invasion and Migration of Oral Squamous Cell Carcinoma by Suppressing Epithelial-Mesenchymal Transition Induced Transcription Factors

Oral squamous cell carcinoma (OSCC) is the most common type of oral malignancy. Numerous therapies have been proposed for its cure. Research is continually being conducted to develop new forms of treatment as current therapies are associated with numerous side-effects. Luteolin, a common dietary flavonoid, has been demonstrated to possess strong anti-cancer activity against various human cancer cell lines. Nevertheless, research into luteolin-based anticancer activity against oral cancer remains scarce. Thus, the objective of this study was to assess the effect of luteolin as an anti-cancer agent. After treatment with luteolin, Ca9-22 and CAL-27 oral cancer cells showed condensed nuclei and enhanced apoptotic rate with evidence of mitochondria-mediated apoptosis. Epithelialmesenchymal transition (EMT) is closely related to tumor migration and invasion. Luteolin suppressed cancer cell invasion and migration in the current study. Elevated expression of E-cadherin, an adherens junction protein, was evident in both cell lines after luteolin treatment. Luteolin also significantly inhibited transcription factors (i.e., N-cadherin, Slug, Snail, Twist, and ZEB-1) that regulated expression of tumor suppressors such as E-cadherin based on Western blot analysis and quantitative PCR. Thus, luteolin could induce mitochondrial apoptosis and inhibit cancer cell invasion and migration by suppressing EMT-induced transcription factors.

A N-glicosilação do EGFR afeta a sinalização intracelular e a estabilidade das Junções Tight em células de câncer colorretal / [ EGFR N-glycosylation affects intracellular signaling and stability of Tight Junctions in Colorectal Cancer Cells]

Introdução: O câncer colorretal (CCR) constitui um importante problema de saúde pública no Brasil e no mundo. Durante a progressão de tumores epiteliais, como o CCR, é frequentemente observada uma desestabilização do complexo juncional apical, composto pelas junções tight (JT) e junções aderentes (JA). O aumento dos níveis de expressão das claudinas, principais proteínas transmembranas constituintes das JT, induz a perda da sua função de barreira e aumenta o potencial maligno das células do CCR. Embora cada vez mais estudos estejam focados em compreender melhor os aspectos moleculares que regulam a estabilidade das TJ, o papel desempenhado por N-glicanos neste processo continua sendo pouco explorado. Objetivo: Assim, o objetivo do presente estudo foi investigar o papel dos N-glicanos na regulação da estabilidade das JT em CCR. Materiais e Métodos: Utilizando a linhagem celular HCT-116 (carcinoma colorretal humano), foi avaliado o efeito do tratamento com dois inibidores de biossíntese de N-glicanos, swainsonina (SW) e tunicamicina (Tun), sobre a estabilidade das JT mediante: citometria de fluxo, Western blot, microscopia eletrônica de transmissão, co-imunoprecipitação e imunofluorescência. A expressão de ácido siálico na superfície celular também foi inibida utilizando análogo fluorinado de ácido siálico (Sia-F). Além disso, foram avaliados o grau de N-glicosilação do Receptor do Fator de Crescimento Epidérmico (EGFR) e os níveis de expressão de claudina-3 (cld-3) em tecidos de pacientes com CCR (n = 21) por imunohistoquímica e Western blot (Protocolo-CEP nº: 84/04). Para este estudo foram consultadas bases de dados internacionais (NCBI e TCGA) a fim de identificar os sítios de N-glicosilação (Asn-XSer/Thr) do EGFR e relatos de mutações nestes sítios em CCR. Utilizando um algoritmo classificador de subtipos de CCR foi avaliada também a expressão de glicogenes e de cld-3 em quatro subtipos moleculares de CCR. Ministério da Saúde Instituto Nacional de Câncer Coordenação de Pós-graduação Resultados: Primeiramente, foi avaliado o efeito de SW e Tun na expressão proteica de vários constituintes das TJ. Foi observado que apenas o tratamento com Tun diminuiu os níveis de expressão de cld-3. A Tun também promoveu, concomitantemente, diminuição dos níveis de fosforilação de proteínas na faixa de peso molecular da cld-3 (22kDa) e reorganização da sua localização celular do citoplasma à membrana. Os resultados mostraram que, após o tratamento com Tun, as células HCT-116 desenvolveram contatos celulares mais estabelecidos. Além disso, a deglicosilação do EGFR promoveu redução dos seus níveis de expressão na membrana celular e também diminuiu tanto os seus níveis de ativação quanto a fosforilação das proteínas downstream ERK e AKT. Foi observado que o tratamento com Sia-F diminuiu tanto a ativação de EGFR quanto os níveis de expressão de cld-3. Os resultados mostraram também que tumores de pacientes com CCR, que expressavam maiores níveis proteicos de cld-3 do que os respectivos tecidos normais adjacentes, exibiram também um maior grau de N-glicosilação do EGFR. Finalmente, não foram encontrados relatos de mutações em sítios de N-glicosilação do EGFR em CCR, porém, foram encontradas diferenças na expressão de glicogenes e de cld-3 entre os quatro subtipos moleculares de CCR. Conclusão: Conjuntamente, os resultados demonstram que a N-glicosilação do EGFR desempenha um papel na regulação da cld-3, contribuindo para uma melhor compreensão da biologia do CCR. Estes achados também sugerem um potencial significado clínico de alterações no padrão de N-glicosilação do EGFR.

Internacionalização, ciência e saúde: a medicina regenerativa global e os mercados paralelos / Internationalization, science and health: global regenerative medicine and the parallel markets

A medicina regenerativa implica em uma mudança de paradigma, a regeneração do organismo ao nível celular ou tecidual – um assunto contemporâneo controverso e de difícil estandardização. O artigo apresenta um resumo das tendências científicas, econômicas, sociais e de regulamentação global nessa área, analisadas em relação a dilemas teóricos relevantes em antropologia médica e sociologia da ciência e da saúde. Em especial, aqueles que tratam da construção de um ‘aparato coletivo de sentido’ para as novas entidades biológicas e ontológicas, a formação da cidadania biológica e a governança pela incerteza. Apresentam-se, também, evidências empíricas sobre um fenômeno chave para a governança e a regulamentação, qual seja a instalação de uma nova demanda transnacional em pesquisa e saúde através de mercados paralelos de óvulos e de terapias celulares em experimentação. Utilizam-se dados qualitativos coletados para uma pesquisa mais abrangente, resenhas jornalísticas e entrevistas com lideranças internacionais. Conclui-se com uma reflexão sobre a importância da governança internacional em ensaios clínicos e dos caminhos a serem explorados, visando uma harmonização da diversidade de práticas normativas.

Regenerative medicine involves a paradigm change due to organism regeneration at cellular and tissue level – a controversial contemporary issue and difficult to regulate. This article presents a summary of the main scientific, economic, social and regulatory global trends, analyzed according to relevant theoretical dilemmas in medical anthropology and in the sociology of science and health. This is especially true of the construction of a ‘collective frame of reference’ on the new biological and ontological entities, the shaping of biological citizenship, and governance through uncertainty. Empirical evidence is also presented on a key aspect in regulation and governance, namely the emergence of a new transnational demand in health research through the establishment of parallel markets for ova and experimental cellular therapies. Qualitative data collected for a broader research paper is analyzed, as well as journal reviews and information gathered during interviews with international leaders. The paper concludes with a discussion on the importance on international governance of clinical trials and on further exploration, towards a multilevel harmonization of a diversity of normative practices.

A low-protein diet during pregnancy prevents modifications in intercellular communication proteins in rat islets

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Altered Transendothelial Transport of Hormones as a Contributor to Diabetes

The vascular endothelium is a dynamic structure responsible for the separation and regulated movement of biological material between circulation and interstitial fluid. Hormones and nutrients can move across the endothelium either via a transcellular or paracellular route. Transcellular endothelial transport is well understood and broadly acknowledged to play an important role in the normal and abnormal physiology of endothelial function. However, less is known about the role of the paracellular route. Although the concept of endothelial dysfunction in diabetes is now widely accepted, we suggest that alterations in paracellular transport should be studied in greater detail and incorporated into this model. In this review we provide an overview of endothelial paracellular permeability and discuss its potential importance in contributing to the development of diabetes and associated complications. Accordingly, we also contend that if better understood, altered endothelial paracellular permeability could be considered as a potential therapeutic target for diabetes.

Dynamic assembly of intercalated disc during postnatal development in the rat myocardium / 生理学报

The intercalated disc (ICD) complex of cardiomyocyte consists of fascia adherens, desmosomes and gap junctions which are mainly constructed by their transmembrane proteins: N-cadherin (N-cad), desmoglein-2 (DSG2) and connexin 43 (Cx43), respectively. The aim of this study was to observe the dynamic changes in colocalization of N-cad, DSG2 and Cx43 with each other in the rat left ventricular myocardium at 1, 7, 14, 28 and 90 day(s) after birth (P1, P7, P14, P28 and P90) using immunofluorescent staining. The results showed that, N-cad, DSG2 and Cx43 located all around the plasma membrane at the P1. These proteins accumulated to the long ends of cardiomyocytes, indicating preliminary formation of the ICD at the P7. The localization of three proteins at the ICD increased progressively, but their lateral localization showed an inverse trend from the P14 to P90. However, Cx43 still kept a certain amount of lateral localization in cardiomyocytes even at the P90 as compared with N-cad and DSG2. Quantitative colocalization of proteins was analyzed by the stereological method. Total percentage of colocalization of N-cad with DSG2 was 33.5% at the P1, and increased to 38.6% at the P7, 9.4% in ICD and 29.2% in lateral side. The total percentage of colocalization of N-cad with DSG2 increased to 65.7% at the P90, ICD colocalization increasing to 60.5% and lateral colocalization decreasing to 5.2%. Total percentage of colocalization of N-cad with Cx43 increased from 10.3% at the P1 to 37.1% at the P90, and only ICD colocalization increased, but lateral colocalization kept about 5%. The colocalization pattern of DSG2 with Cx43 was similar to that of N-cad with Cx43. Total percentage of colocalization of N-cad with DSG2 was higher than those of N-cad or DSG2 with Cx43. The above results suggest that the formation of mechanical junctions at the ICD of cardiomyocyte is prior to that of electrochemistry junctions during postnatal development. In other words, cardiomyocyte growth needs a stable mechanical environment at first.

Deorganização do complexo juncional aplical mediado pelas proteínas e- caderina e claudinas durante a progressão do câncer colorretal: vias de sinalização envolvidas / [Deorganization of the apical junctional complex mediated by e-caderine and claudine proteins during the progression of colorretal cancer: signaling routes involved]

O câncer colorretal apresenta a quarta maior taxa de mortalidade relacionada ao câncer no mundo, a qual está intimamente ligada ao desenvolvimento de metástase. No início do processo de malignização, células epiteliais sofrem desregulação da adesão célulacélula, que leva ao desenvolvimento da transição epitélio-mesenquimal. O sistema de adesão célula-célula é mantido pelo complexo juncional apical, constituído pelas junções tight e aderentes, que desempenha um importante papel na homeostase epitelial, regulando diversos eventos, como proliferação, diferenciação e sinalização celular. Neste contexto, a desregulação funcional das claudinas e E-caderina, principais componentes das junções tight e aderentes respectivamente, desempenha um papel crucial no aumento do potencial tumorigênico de diversos tipos de tumores epiteliais. No presente estudo, foi avaliado o papel das vias de sinalização ativadas pelo fator de crescimento epidermal na modulação da expressão e função das claudinas, assim como o envolvimento da Na,K-ATPase e vias de sinalização downstream na regulação do complexo juncional apical utilizando o glicosídio ouabaína, conhecido por inibir a Na,KATPase, sendo esses eventos relacionados com a progressão do câncer colorretal. Inicialmente, mostramos que o fator de crescimento epidermal aumentou a expressão da claudina-3 em células de adenocarcinoma colorretal HT-29, evento relacionado ao aumento da migração celular e formação de colônias dependente e independente de ancoragem. Observamos ainda que as vias de sinalização ERK1/2 e PI3K-Akt estão envolvidas na modulação destes efeitos, visto que a inibição farmacológica das mesmas bloqueou estes eventos. Através de manipulação genética, mostramos também que a superexpressão da claudina-1 resultou na diminuição da migração celular; contudo, a superexpressão da claudina-3 não alterou o potencial migratório das células. Além disso, a superexpressão da claudina-3, mas não da claudina-1, desregulou a função de barreira das junções tight, aumentando o fluxo paracelular de macromoléculas. De maneira adicional, um aumento na formação de colônias dependente e independente de ancoragem foi observado em células que superexpressavam claudina-3, enquanto nenhuma mudança no potencial de formação de colônias foi observada em células que superexpressavam a claudina-1. Em seguida, demonstramos que o tratamento com a ouabaína resultou na redução dos níveis protéicos da ß1 Na,K-ATPase e redistribuição celular das proteínas de junção aderente E-caderina e ß-catenina, assim como da α1 Na,K-ATPase. Além disso, a ouabaína aumentou os níveis protéicos da claudina-3, desregulando a função de barreira das junções tight e aumentou a viabilidade e proliferação celular, durante períodos iniciais de tratamento. De forma adicional, observamos que os eventos induzidos por ouabaína foram dependentes da ativação da via de sinalização ERK1/2, mas, em contraste a estudos anteriores, esta cascata de sinalização foi independente da presença de caveola. Em conclusão, nossos dados ajudam no melhor entendimento sobre as vias de sinalização envolvidas com a desregulação do complexo juncional apical durante a progressão do câncer colorretal. Além disso, os resultados do nosso estudo pode constituir uma base para postular possíveis alvos moleculares para futuras aplicações terapêuticas no tratamento deste tipo de câncer.

Perda da adesão célula-célula mediada pela E-caderina em câncer colo-retal: vias de sinalização envolvidas

Durante a progressão do câncer colo-retal, alguns eventos são cruciais para iniciar o processo metastático. Estes eventos envolvem a desorganização dos contatos célula-célula, aumento da motilidade e invasividade celular, os quais fazem parte de um programa morfogenético conhecido como transição epitélio-mesenquimal (TEM). A adesão célula-célula é controlada por um sistema de proteínas de membrana, conhecido como complexo juncional apical, o qual é formado pelas junções tight e aderentes. A glicoproteína transmembrana E-caderina é a principal proteína das junções aderentes e desempenha um importante papel na regulação da organização e manutenção da adesão célula-célula, e de sinais intracelulares que medeiam a proliferação e motilidade celular. No entanto, os mecanismos celulares e moleculares que regulam a desorganização das junções aderentes mediada pela Ecaderina, no câncer colo-retal, ainda não estão definidos. No presente estudo usando uma linhagem celular de câncer de cólon humano, Caco-2, foram avaliadas as vias de sinalização envolvidas na perda de adesão célula-célula mediada pela Ecaderina e aumento do potencial migratório causado por TPA e EGF, assim como o envolvimento da Na+/K+-ATPase na desorganização das junções aderentes induzida pela ouabaína. Nossos resultados mostraram que os tratamentos com 200 nM de TPA e 100 ng/mL de EGF causaram desorganização das junções aderentes, e este evento foi modulado de forma diferencial pelas proteínas ERK1/2 e Src. A proteína ERK1/2 participando da modulação nos períodos iniciais dos tratamentos e a proteína Src atuando em resposta tardia. Além disso, o tratamento com estes agentes induziu um aumento da motilidade celular, sendo este efeito revertido pelo tratamento com o inibidor de Src, o PP1. Por outro lado, o tratamento com 10 e 100 μM de ouabaína também causou alterações morfológicas das junções aderentes e redistribuição da E-caderina. Este efeito parece ser modulado pela proteína ERK1/2, considerando o aumento da atividade desta proteína analisado em paralelo. Adicionalmente, foi observado que a ouabaína causou redução dos níveis protéicos a subunidade 1 da Na+/K+-ATPase e um aparente acúmulo citoplasmático da b-mas não da a-catenina. Em conclusão, nossos resultados indicam que a desorganização da adesão célula-célula mediada pela E-caderina, provocada por TPA e EGF, pode ser modulada inicialmente por ERK1/2 e posteriormente pela Src, sendo esta última também responsável pelo aumento da motilidade celular. E, além disso, os experimentos com ouabaína mostraram um papel importante da subunidade b1 da Na+/K+-ATPase na desorganização das junções aderentes e da proteína ERK1/2 como moduladora deste evento. Nossos resultados podem contribuir para o entendimento dos mecanismos que medeiam a desorganização dos contatos célula-célula mediado pela E-caderina e, de forma geral, da progressão do carcinoma colo-retal.

During tumor development, some events are crucial to trigger the metastatic process. These events involve the disassembly of cell-cell contacts, increase of cell motility and invasivity, which are part of a morphogenetic program called epithelial mesenchymal transition (EMT). The cell-cell adhesion is controlled by a system of membrane proteins, known as the apical junctional complex, which is constituted for tight and adherent junctions. The transmembrane glycoprotein E-cadherin is the main adherens junction protein that plays a critical role in the organization and maintenance of cell-cell adhesion, and regulates intracellular signals to mediate cell proliferation and motility. Nevertheless, the cellular and molecular mechanisms that regulate the disassembly of the E-cadherin-mediated adherens junction in colorectal cancer, remain to be defined. In present study, using a human colon cancer cell line, Caco-2, we evaluate cell signaling pathways involved with the disassembly of Ecadherin- mediated cell-cell adhesion and the migratory potential caused by TPA and EGF. Furthermore, the roles of Na+/K+-ATPase on the adherens junction disassembly caused by ouabain, as well as cellular events involved also were analyzed. Our results show that treatment with 200 nM TPA and 100 ng/mL EGF caused adherens junction disruption in an event differentially modulated by ERK1/2 and Src proteins. ERK1/2 protein modulates adherens junction disassembly in early periods of treatment whereas Src protein in a later response. Besides, treatment with these agents induced an increase of cell motility, a process modulated by Src. On the other hand, treatment with 10 and 100 μM ouabain also caused morphological alterations of adherens junction and E-cadherin redistribution, and these events seem to be modulated by ERK1/2, considering the increased activity of this protein analyzed in parallel. Additionally, we observed reduction of protein levels of the Na+/K+-ATPase b1-subunit and apparent accumulation of b-catenin, but not a-catenin at the cytoplasm, after treatment with ouabain. In conclusion, our results indicate that disassembly of E-cadherin-mediated cell-cell adhesion, promoted by TPA and EGF may be initially modulated by ERK1/2 and subsequently by Src. This later protein was also responsible by regulate the increase of cell motility induced by these agents. Furthermore, we showed that ouabain induces adherens junction disassembly concomitantly to decreasing protein levels of the Na+/K+-ATPase b1- subunit, and these events may be modulated by ERK1/2. Our findings may contribute for the understanding of mechanisms that mediate disassembly of E-cadherinmediated cell-cell contacts and of a general manner on the progression of colorectal carcinoma.

Effects of Angiotensin II on ZO-1 in Glomerular Epithelial Cells / 대한신장학회지

PURPOSE: Angiotensin II plays a potent role in renal injury not only by vasoconstrictive effects but also by biochemical effects. We investigated the effect of angiotensin II on ZO-1 (zonular occludens-1), a component of the slit diaphragm domain connecting slit diaphragm structure and actin cytoskeleton, in the glomerular epithelial cells (podocytes) for the glomerular damage. We tried to find that this effect could be prevented by losartan, an angiotensin II type 1 receptor blocker. METHODS: Glomerular epithelial cells were treated with various concentrations of angiotensin II and losartan. The distribution of ZO-1 was observed by confocal microscope and the change of ZO-1 expression was measured by Western blotting and RT-PCR. RESULTS: The intensities of fluorescences and bands of ZO-1 protein were decreased by angiotensin II in a dose-dependent manner by confocal microscopy and Western blot analysis, respectively. ZO-1 also moved from peripheral to inner cytoplasm and lost its linear pattern. These distributional changes of ZO-1 protein by angiotensin II were reversed by losartan in a dose-dependent manner. Angiotensin II reduced the amount and mRNA expresssion of ZO-1 which were also reversed by losartan. CONCLUSION: Angiotensin II decreases the amount of ZO-1 protein and changes its localization through angiotensin II type 1 receptor. These findings suggest that angiotensin II-added condition induces the cytoplasmic translocation and suppresses the production of ZO-1 in podocytes at transcriptional level, and could be prevented by angiotensin receptor antagonists.

Transmission and Scanning Electron Microscopic Studies on the Sinusoid and the Migration of Erythroid Cell in Rat Fetal Liver / 대한해부학회지

For studies on the developmental stages of migrating erythroid cells and the development of sinusoid, transmission and scanning electron microscopic observations were undertaken on rat fetal liver in 13, 15, 17, 19, 21 days of gestation. The results obtained were as follows. 1. The hepatic sinusoidal endothelium were mainly non-fenestrated cell and fenestrated cell with diaphragm before 17 days of gestation, but fenestrated cells without diaphragm began to appear after 17 days of gestation. Two types of fenestrae were observed, free and clustered fenestrae, but both types were not involved in migration of erythroid cells. 2. Endothelial cell was continuous with neighboring cells by intercellular junctions between lateral cytoplasmic processes with zonula adherens, and between perinuclear cytoplasms with macula adherens. 3. After 13 days of gestation, Kupffer cells showed as matured cell morphology of irregular shape with long cytoplasmic processes into hepatic cord and perisinusoidal space. 4. Migrating erythroid cells in rat fetal liver sinusoid were mainly consisted of immature erythroblasts from proerythroblast to acidophilic erythroblast. The migration occurred through the migrating pores formed on the various sites of the endothelial cytoplasm into the hepatic sinusoidal lumen with no relation to the maturation stages of erythroblast and endothelial cell. In summary, the migration of erythroid cells in the sinusoid of rat fetal liver occurred through the invasion and migration pores transiently formed at various sites of endothelial cytoplasm, and migrating erythroid cells were mainly nucleated immature types.

Invasion Suppressor Role of E-Cadherin in Epithelial Cancer Cell Lines

BACKGROUND: The generation of the invasiveness in transfromed cells represents an essential step of tumor progression. The primary cause of the scattering of the cells in invasive carcinoma is a loss of the integrity of the intercellular adherens junction often involving loss of a functional cell-cell adhesion molecule E-cadherin. Therefore, the perturbation of E-cadherin function causes diaggregation of tumor cells and may promote the invasion and metastases. OBJECTIVE: The reduction in E-cadherin activity seems to correlate with the infiltrative ability of tumor cells. The purpose of this study was to compare the E-cadherin expression among different cell lines which were normal to undifferentiated and to check the virtual relationaship between E-cadherin and invasiveness. METHODS: We used 5 cell lines, HaCaT, A431, C3, SiHa and HeLa cell. To check the expression patterns and amounts of E-cadherin in each cell line, immunofluorescence staining, Western blot anlysis and Northern blot analysis were done. An in vitro invasion assay using the collagen gel and MRC-5 fibroblast under the influence of HECD-1 antibody which block the E-cadherin function was done to measure the invasiveness of tumor cells. Collagenase activity in culture supernatants of each cell were analyzed by zymography. RESULTS: Immunofluorescence staining revealed a homogenously well preserved pattern in HaCat, A431, C3 cells. SiHa cells showed patch distribution but HeLa cells did not express the E-cadherin. Western blot analysis and Northern blot results largely corresponded with the immunofluorescence results. The in vitro invasion assay revealed invasion into the collagen matrix of the HeLa cells. When HECD-1 antibody was added to the medium, other cells showed partially disrupted stratification. The collagenolytic activity at 72 kDa sixe was detected in the HeLa cell line only. CONCLUSION: There is an inverse relationship between E-cadherin expression and tumor invasion. Therefore, through their regulation of cell adhesion and motility, cadherin plays a crucial role in the suppression of tumor invasion and metastasis.

The Long-term Effects of Experimental Total Retinectomy

Experimental total retinectomy was performed in the pigmented rabbt eyes to investigate its long-term effects on the operated and nonoperated opposite eyes in clinical and histological aspects. Measurement of intraocular pressures, slit lamp biomicroscopy, and indirect ophthalmoscopy were performed before operation and one, two, three and six months after operation. The eyeballs were enucleated six months after operation to make specimens for light and electron microscopy. There was no statistically significant change of intraocular pressure between preoperative and postopzrative measurements during the experimental period. Rubeosis iridis, intraocular hemorrhage and phthisis bulbi were not noticed in the operated and the opposite eyes. Light microscopic examination showed the cangestion of the choroidal vessels. Transmission electron microscopic examination showed apical mounding of the retinal pigment epithelium. Apical processes were short and reduced in number. There were scattered areas of retinal pigment epithelial cdl proliferation. Apical processes of retinal pigment epithelial cells interdigitated with surface processes of the proliferating retinal pigment epithelial cells. There were numerous melanosomes in the cytoplasm of the proliferating retinal pigment epithelial cells. Zonula occludens and zonula adherens between the retinal pigment epithelial cells were well preserved. These results suggest that total retinectomy could preserve the eyeball in the rabbit eyes during the experimental period, total retinectomy, intraocular pressure, choroidal congestion, phthisis bulbi, retinal pigment epithelium