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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression pattern of E- and P-cadherin in human carcinomas has been reported by many laboratories. However, little is known about the involvement of other cadherin types in human carcinomas. cDNA clones for a cadherin molecule were isolated from a cDNA library of human hepatocellular carcinoma cells which lacked E- and P-cadherin expression but exhibited cell aggregation activity mediated by an unknown cadherin, and they were subjected to sequence analysis. The overlapped clones covered 4315 nucleotides and were found to encode a typical cadherin molecule consisting of 790 amino acids. Since the deduced amino acid sequence was identical to a partially available human cadherin-6 sequence except for two amino acid residues, the clones were considered to be human cadherin-6 cDNAs encoding the entire open reading frame. The deduced amino acid sequence also showed extremely high homology with recently reported rat K-cadherin, 97% for the putative mature protein, suggesting that cadherin-6 is the human counterpart of rat K-cadherin. Expression of cadherin-6 in various human normal tissues and carcinoma cells was examined by Northern blot analysis using a specific probe corresponding to the signal and precursor sequence. Among normal tissues examined, brain, cerebellum, and kidney showed strong expression of cadherin-6, whereas lung, pancreas, and gastric mucosa showed weak expression. Transcripts of cadherin-6 were not detected in normal liver, whereas four of six hepatocellular carcinoma cell lines examined expressed cadherin-6 abundantly. As reported for rat K-cadherin, three renal carcinoma cell lines also expressed cadherin-6 strongly. The most interesting finding was obtained for small cell lung carcinoma lines. Among 15 of such cell lines examined, all of 11 cadherin-6-positive lines were classified into the classic type, whereas the negative cell lines were all of the variant type. The present results suggest that besides E- and P-cadherin, other cadherin molecules are expressed in human cancers and are responsible for additional biological properties of the carcinoma cells.
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PMID:Isolation and sequence analysis of human cadherin-6 complementary DNA for the full coding sequence and its expression in human carcinoma cells. 774 25

Previous studies have shown that in vitro expression of the neural cell adhesion molecule (N-CAM) can be regulated by the products of homeobox genes HoxB9, -B8, and -C6. N-CAM is a Ca(2+)-independent immunoglobulin-related CAM that plays an important role in neural development. In the present study, we investigated whether the liver cell adhesion molecule (L-CAM) a member of the Ca(2+)-dependent CAM family (cadherins) is also regulated by homeobox-containing genes. In transient cotransfection experiments of NIH 3T3 cells, we observed that both HoxD9 and liver-enriched POU-homeodomain transcription factor, HNF-1, activated chloramphenicol acetyltransferase gene reporter constructs containing the L-CAM promoter and an enhancer present in the second intron of the chicken L-CAM gene. Using electrophoretic mobility-shift assays, we found that components of cell extracts from NIH 3T3 cells transfected with HoxD9 bound to a small region of the L-CAM enhancer having a consensus sequence that is a putative binding site for HNF-1. Components of extracts from the chicken hepatoma cell line LMH that had been transfected with an HNF-1 expression vector also bound to this same site. In nuclear run-on experiments with nuclei from LMH cells that were transfected with expression vectors for HoxD9 or HNF-1, L-CAM RNA levels were increased 33-fold and 4-fold respectively. Using the same run-on procedure, it was confirmed that nuclei prepared from normal embryonic chicken liver cells expressed the RNAs for HoxD9, HNF-1, and L-CAM. Taken together with previous observations, these data raise the possibility that homeobox-containing genes will have a widespread role in the place-dependent expression of CAMs belonging both to immunoglobulin-related and to cadherin families.
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PMID:Regulation in vitro of an L-CAM enhancer by homeobox genes HoxD9 and HNF-1. 791 99

A novel member of the cadherin family of cell adhesion molecules has been characterized by cloning from rat liver, sequencing of the corresponding cDNA, and functional analysis after heterologous expression in nonadhesive S2 cells. cDNA clones were isolated using a polyclonal antibody inhibiting Ca(2+)-dependent intercellular adhesion of hepatoma cells. As inferred from the deduced amino acid sequence, the novel molecule has homologies with E-, P-, and N-cadherins, but differs from these classical cadherins in four characteristics. Its extracellular domain is composed of five homologous repeated domains instead of four characteristic for the classical cadherins. Four of the five domains are characterized by the sequence motifs DXNDN and DXD or modifications thereof representing putative Ca(2+)-binding sites of classical cadherins. In its NH2-terminal region, this cadherin lacks both the precursor segment and the endogenous protease cleavage site RXKR found in classical cadherins. In the extracellular EC1 domain, the novel cadherin contains an AAL sequence in place of the HAV sequence motif representing the common cell adhesion recognition sequence of E-, P-, and N-cadherin. In contrast to the conserved cytoplasmic domain of classical cadherins with a length of 150-160 amino acid residues, that of the novel cadherin has only 18 amino acids. Examination of transfected S2 cells showed that despite these structural differences, this cadherin mediates intercellular adhesion in a Ca(2+)-dependent manner. The novel cadherin is solely expressed in liver and intestine and was, hence, assigned the name LI-cadherin. In these tissues, LI-cadherin is localized to the basolateral domain of hepatocytes and enterocytes. These results suggest that LI-cadherin represents a new cadherin subtype and may have a role in the morphological organization of liver and intestine.
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PMID:Liver-intestine cadherin: molecular cloning and characterization of a novel Ca(2+)-dependent cell adhesion molecule expressed in liver and intestine. 820 63

We have analyzed the composition of the tumor stroma and the expression of cell-matrix and cell-cell adhesion molecules in 11 cases of fibrolamellar carcinoma of the liver (FLC), in comparison with 34 cases of hepatocellular carcinoma and 8 cases of focal nodular hyperplasia. Fibrolamellar carcinoma was characterized by the presence of large amounts of tenascin in tumor stroma and by the scarce expression of basement membrane components at the contact of neoplastic clusters. Like normal hepatocytes, neoplastic cells constantly expressed the alpha1 integrin chain, lacked the beta4 integrin chain, and coexpressed E-cadherin and the hepatocyte N-related cadherin. Abnormalities in the expression of cell adhesion molecules, including altered cadherin expression, alphaV integrin chain induction, and CD44 expression, were detected in the majority of cases. The composition of the tumor stroma and the pattern of expression of cell adhesion molecules in fibrolamellar carcinoma were reminiscent of those observed in grade III and grade IV hepatocellular carcinomas. Our results therefore show that, despite its slow local growth and good prognosis, fibrolamellar carcinoma expresses many characteristics usually associated with clinically aggressive malignancies. Further studies are needed to identify the factors responsible for the apparent dissociation between clinical behavior and biological characteristics in this tumor.
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PMID:Fibrolamellar carcinoma of the liver: composition of the extracellular matrix and expression of cell-matrix and cell-cell adhesion molecules. 890 87

The action of Ca(2+)-dependent cell-cell adhesion molecules (cadherins) on cell-to-cell channel-mediated intercellular communication was investigated in mouse L and rat Morris hepatoma cells. These cells fail to adhere to one another in aggregation assays and thus seem to lack cell adhesion molecules. Expression of exogenous cadherin induced strong cell-cell adhesion in both cell types, but had opposite effects of communication, causing inhibition in L cells and improvement in hepatoma cells. Both cells express the connexin43 cell-to-cell channel protein. By western blot we found no cadherin-specific changes in connexin43 protein in either cell type, but connexin43 gap junctional plaque staining, i.e. connexin43 localization to cell-cell junctions, was inhibited in L cells and facilitated in hepatoma cells. In addition we found that the inhibitory effect is largely abolished by blockers of glycosylation. Cadherin-cadherin interactions are known to trigger cell type-specific intracellular signal cascades resulting in diverse end effects, and gap junctional communication/plaque formation seems a further example of such cell type-specificity.
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PMID:An inhibition of gap-junctional communication by cadherins. 905 83

Desomosomes are cell-cell adhesion structures of epithelia and some non-epithelial tissues, such as heart muscle and the dendritic reticulum of lymph node follicles, which on their cytoplasmic side anchor intermediate filaments at the plasma membrane. Besides clusters of specific transmembrane glycoproteins of the cadherin family (desmogleins and desmocollins), they contain several desmosomal plaque proteins, such as desmoplakins, plakoglobin, and one or more plakophilins. Using recombinant DNA and immunological techniques, we have identified a novel desmosomal plaque protein that is closely related to plakophilins 1 and 2, both members of the "armadillo-repeat" multigene family, and have named it plakophilin 3 (PKP3). The product of the complete human cDNA defines a protein of 797 amino acids, with a calculated molecular weight of 87.081 kDa and an isoelectric point of pH 10.1. Northern blot analysis has shown that PKP3 mRNA has a size of approximately 2.9 kb and is detectable in the total RNA of cells of stratified and single-layered epithelia. With the help of specific poly- and monoclonal antibodies we have localized PKP3, by immunofluorescence or immunoelectron microscopy, to desmosomes of most simple and almost all stratified epithelia and cell lines derived therefrom, with the remarkable exception of hepatocytes and hepatocellular carcinoma cells. We have also determined the structure of the human PKP3 gene and compared it with that of plakophilin 1 (PKP1). Using fluorescence in situ hybridization, we have localized the human genes for the three known plakophilins to the chromosomes 1q32 (PKP1), 12p11 (PKP2) and 11p15 (PKP3). The similarities and differences of the diverse plakophilins are discussed.
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PMID:Plakophilin 3--a novel cell-type-specific desmosomal plaque protein. 1037 65

We previously found by chance that N-nitrosomorpholine (NMOR) given after a multi-carcinogenic treatment induces liver carcinomas with 56% lung metastasis, and it was confirmed that hepatocellular carcinoma (HCC) with 100% lung metastasis was produced by 24-week treatment with NMOR and additional treatment with diethylnitrosamine (DEN). In the present study, we modified the duration of NMOR to establish an animal model with a simple experimental protocol and an appropriate experimental duration which would facilitate further study of the mechanisms of metastasis and antimetastatic agents. The results revealed DEN exposure followed by a 16-week treatment with NMOR to be a most efficient method for the induction of HCC metastasizing to the lung. Loss of cadherin, demonstrated immunohistochemically, occurred in an early stage of carcinogenesis, and this was reflected in malignant conversion of primary lesions. This model, with its essential similarities to malignant tumor behavior in man, should find application not only for elucidation of the mechanisms underlying metastasis, but also in the development of anti-metastatic agents.
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PMID:Establishment of an in vivo highly metastatic rat hepatocellular carcinoma model. 1062 28

The cadherin-mediated cell-cell adhesion system plays a critical role in normal development and morphogenesis. Inactivation of this system is thought to be responsible for cancer invasion and metastasis. A human hepatocellular carcinoma (HCC) cell line, KYN-2, was observed to have great potential for intrahepatic metastasis when orthotopically implanted into the liver of SCID mice. In vitro cultures of KYN-2 cells showed that they formed trabecular structures in suspension but lost tight cell-cell adhesion and became scattered when attached to a substratum such as collagen or fibronectin. In response to adhesion to the substratum, subcellular colocalization of E-cadherin and actin filaments were shown to be reduced, and a significant amount of alpha-catenin was dissociated from the E-cadherin-catenin complex in KYN-2 cells. These changes of cell-cell adhesion were blocked by inhibitory monoclonal antibodies against beta1 and beta5 integrins. We found that c-Src was coimmunoprecipitated with E-cadherin-catenin complex and was tyrosine-dephosphorylated and activated in the adherent cells. The tyrosine dephosphorylation of c-Src was induced by cell adhesion to the substratum and inhibited by addition of inhibitory monoclonal antibodies against beta1 and beta5 integrins. These findings indicate that integrin-mediated cell-substratum adhesion inhibits cadherin-mediated cell-cell adhesion, possibly through c-Src activation, and suggest that this cross-talk mediates transient inactivation of the cadherin system and plays an important role in intrahepatic metastasis of human HCC. Modulation of this interaction might provide a new approach to prevent metastasis and recurrence of HCC.
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PMID:Loss of cell-cell contact is induced by integrin-mediated cell-substratum adhesion in highly-motile and highly-metastatic hepatocellular carcinoma cells. 1074 74

Cell-cell adhesiveness, involving the adherens junction system including homophilic adhesion of cadherin and intracellular catenins, is a critical factor for tumor cell invasion and metastasis. We evaluated the levels of E-cadherin and beta-catenin in hepatoma cell sublines with high and low metastatic capacities. Stimulation of these cells with serum growth factors for more than 3 h after 24 h of starvation caused decreases in levels of E-cadherin and beta-catenin in the subline with high metastatic capacity, G-5. In contrast, no significant changes were observed in the subline with low metastatic capacity, G-1. Concomitantly with the decreases in E-cadherin and beta-catenin levels, G-5 cells were dissociated and detached from the culture dish, although G-1 cells again showed no morphological alterations. These in vitro results reflected the in vivo metastatic potencies of these hepatoma sublines, and further suggested the importance of the adherens junction system in determining metastatic potency of these parenchymal tumor cell lines as in epithelial/endothelial tumors.
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PMID:Correlation between metastatic potency and the down-regulation of E-cadherin in the mouse hepatoma cell lines G-1 and G-5. 1085 34

beta-catenin has functions both in the cadherin-mediated cell adhesion system and in the signalling pathway that mediates dorsal axis patterning in the embryo; it has been shown to be aberrantly expressed or mutated in diverse types of human tumour, but the biological significance of this remains to be clarified. To elucidate the clinical implications of aberrant beta-catenin expression and the potential differences between mutant and wild-type beta-catenin protein expression in hepatocellular carcinoma (HCC), the protein expression was analysed by immunohistochemical staining, supplemented by the analysis of gene mutation. Among 372 unifocal primary HCCs, beta-catenin was detected in the tumour cell membrane alone in 272 tumours (group A) and also in the nuclei in 100 (group B). In group A, 148 tumours had decreased beta-catenin expression, but the reduction did not correlate with invasion or prognosis. When compared with group A, however, group B had significantly lower frequencies of hepatitis B surface antigen carrier (p=0.015), and alpha-fetoprotein elevation (p=0.0003), but more often had non-invasive HCC (p<0.001) and better survival (p=0.01). Nuclear beta-catenin expression strongly correlated with mutation of the gene (p<0.00001). In group B, HCC with mutant nuclear beta-catenin correlated positively with non-invasive (stage 1) tumour and inversely with portal vein tumour thrombi (stage 3 HCC), and had significantly better 5-year survival, p<0.001 and p<0.0003, respectively. These results suggest that beta-catenin mutation plays an important role in the tumourigenesis of a subset of HCC of good prognosis, and that mutant and wild-type nuclear beta-catenin proteins are not functionally equivalent.
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PMID:Expression of mutant nuclear beta-catenin correlates with non-invasive hepatocellular carcinoma, absence of portal vein spread, and good prognosis. 1116 21


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