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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of the cell-cell adhesion molecules E- and P-cadherin has been analyzed in seven mouse epidermal keratinocyte cell lines representative of different stages of epidermal carcinogenesis. An inverse correlation between the amount of E-cadherin protein and tumorigenicity of the cell lines has been found, together with a complete absence of E-cadherin protein and mRNA expression in three carcinoma cell lines (the epithelioid HaCa4 and the fibroblastoid CarB and CarC cells). A similar result has been detected in tumors induced in nude mice by the cell lines, where induction of E-cadherin expression takes place in moderately differentiated squamous cell carcinomas induced by HaCa4 cells, although at much lower levels than in well-differentiated tumors induced by the epithelial PDV or PDVC57 cell lines. Complete absence of E-cadherin expression has been observed in spindle cell carcinomas induced by CarB or CarC cells. P-cadherin protein was detected in all cell lines that exhibit an epithelial (MCA3D, AT5, PDV, and PDVC57) or epithelioid (HaCa4) morphology, as well as in nude mouse tumors, independent of their tumorigenic capabilities. However, complete absence of P-cadherin was observed in the fibroblast-like cells (CarB and CarC) and in spindle cell carcinomas. The introduction of an exogenous E-cadherin cDNA into HaCa4 cells, or reactivation of the endogenous E-cadherin gene, leads to a partial suppression of the tumorigenicity of this highly malignant cell line. These results suggest a role for E-cadherin in the progression to malignancy of mouse epidermal carcinogenesis. They also suggest that the loss of both E- and P-cadherin could be associated to the final stage of carcinogenesis, the development of spindle cell carcinomas.
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PMID:A role for the E-cadherin cell-cell adhesion molecule during tumor progression of mouse epidermal carcinogenesis. 191 52

We have compared expression of involucrin, E-cadherin and P-cadherin in cultures of normal keratinocytes and in five different lines derived from squamous cell carcinomas (SCCs), using Northern analysis and immunofluorescence. In normal keratinocytes there was an inverse correlation between P-cadherin and involucrin expression, whereas E-cadherin was expressed by both basal and terminally differentiating cells. In SCC lines involucrin expression was lower than in normal keratinocytes, and there was variable expression of P- and E-cadherin: E-cadherin mRNA levels tended to be lower in SCC lines than in normal keratinocytes, whereas P-cadherin levels were similar. Our results are consistent with observations of cadherin expression in vivo and suggest that the cultures provide a useful experimental model for investigating the role of cadherins in determining the spatial organization of normal and neoplastic keratinocytes.
Carcinogenesis 1991 Jul
PMID:Expression of E-cadherin, P-cadherin and involucrin by normal and neoplastic keratinocytes in culture. 207 May 2

Considerable controversy exists concerning the value of histomorphological data in the assessment of the malignant potential of prostatic carcinomas. We investigated the expression pattern of E-cadherin in human prostate at the translational level. E-cadherin is a specific epithelial cell-cell adhesion molecule which has previously been found to be expressed in well-differentiated non-invasive carcinoma cell lines but is lost in many poorly differentiated invasive cell lines. The E-cadherin expression pattern in the prostate samples was correlated with histopathological findings in the same specimens. We found strong E-cadherin expression in normal prostate and benign prostatic hyperplasia. A decrease in or loss of E-cadherin was seen in 13 of 14 locally advanced and in 8 of 9 poorly differentiated prostatic carcinomas. We conclude that downregulation of E-cadherin expression plays a role in prostate carcinogenesis and invasiveness.
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PMID:E-cadherin: a marker for differentiation and invasiveness in prostatic carcinoma. 750 64

Using immunostaining, immunoblot, reverse-transcriptase polymerase chain reaction and Southern blot, we found that expressions of CD44 isoforms and E-cadherin were very closely linked and were correlated with the differentiation status in human urothelial cell lines and clinical specimens of transitional cell carcinoma. Normal urothelium, well to moderately differentiated cell lines and surgical samples expressed E-cadherin and large CD44 isoforms containing exon v6, which was pivotal in metastasis of rat pancreatic cell line model. Poorly differentiated cell lines and surgical samples, were E-cadherin-negative and expressed primarily standard form CD44, which did not contain exon v6. We concluded that CD44v6 isoforms and E-cadherin were both down-regulated during the carcinogenesis of urothelium. The large exon v6 containing CD44 isoforms were readily detected in normal urothelium, therefore, were not likely linked to cancer metastasis. E-cadherin and CD44v6 may be used as differentiation markers for human urothelial tumors. Immunohistochemical study solely with antibody against epitopes encoded by exon v6 alone is not informative enough as other alternatively spliced exons may change the function of CD44v6 isoforms.
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PMID:Correlation of expression of CD44 isoforms and E-cadherin with differentiation in human urothelial cell lines and transitional cell carcinoma. 753 58

Previous studies on the cell-cell adhesion molecules P- and E-cadherin have shown that P-cadherin is not expressed in breast cancer. In contrast, the expression of E-cadherin is a normal event in these tumors, but a reduction in the levels of this molecule in neoplastic cells is associated with the histological type, high histological grade, greater tumor size, and metastasis. The expression pattern of P- and E-cadherin were immunohistochemically studied in tissue sections from normal breast tissue, benign breast lesions, and 57 infiltrating breast carcinomas. Cadherin expression was analyzed in parallel with pathological features and the immunohistochemical expression of estrogen and progesterone receptors in breast carcinomas. P-cadherin was detected in the myoepithelial cells and E-cadherin in luminal epithelial cells from normal breast and benign breast lesions. P-cadherin expression was detected in 9 of 45 cases (20%) of infiltrating ductal carcinomas of no special type; none of the special histological types that were analyzed (7 infiltrating lobular carcinomas, 3 colloid carcinomas, and 2 infiltrating papillary carcinomas) expressed P-cadherin. In infiltrating ductal carcinomas, P-cadherin expression correlated significantly with a reduction in E-cadherin expression, histological grade (all cases were grade III tumors), and hormone receptor content (8 of 9 cases were estrogen and progesterone receptor negative). Although E-cadherin was not found in the 7 infiltrating lobular carcinomas, it was present in the remaining histological types and was preserved in 15 infiltrating ductal and 3 colloid and 2 papillary carcinomas and was reduced in 30 infiltrating ductal carcinomas. In addition, a reduction in E-cadherin expression was significantly associated with high histological grade and a lack of steroid hormone receptors in infiltrating ductal carcinomas. No apparent relationship was found between P- and E-cadherin expression and tumor size and axillary lymph node metastasis. The distinct patterns of P- and E-cadherin expression observed in this study strongly suggest a differential role for these cadherins in human breast carcinogenesis.
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PMID:Anomalous expression of P-cadherin in breast carcinoma. Correlation with E-cadherin expression and pathological features. 753 41

A number of genetic changes have been documented in prostate cancer, ranging from allelic loss to point mutations and changes in DNA methylation patterns (summarized in Fig. 1). To date, the most consistent changes are those of allelic loss events, with the majority of tumors examined showing loss of alleles from at least one chromosomal arm. The short arm of chromosome 8, followed by the long arm of chromosome 16, appear to be the most frequent regions of loss, suggesting the presence of novel tumor suppressor genes. Deletions of one copy of the Rb and p53 genes are less frequent, as are mutations of the p53 gene, and accumulating evidence suggests the presence of an additional tumor suppressor gene on chromosome 17p, which is frequently inactivated in prostate cancer. Alterations in the E-cadherin/alpha-catenin-mediated cell-cell adhesion mechanism appear to be present in almost half of all prostate cancers and may be critical to the acquisition of metastatic potential of aggressive prostate cancers. Finally, altered DNA methylation patterns have been found in the majority of prostate cancers examined, suggesting widespread alterations in methylation-modulated gene expression. The presence of multiple changes in these tumors is consistent with the multistep nature of the transformation process. Finally, efforts to identify prostate cancer susceptibility loci are under way and may elucidate critical early events in prostatic carcinogenesis.
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PMID:Genetic alterations in prostate cancer. 758 26

A number of genetic changes have been documented in prostate cancer, ranging from allelic loss to point mutations and changes in DNA methylation patterns (summarized in Fig. 1). The most consistent changes seen are those of allelic loss events, with the majority of tumours examined showing loss of alleles from at least one chromosomal arm. The short arm of chromosome 8, followed by the long arm of chromosome 16, seem to be the most frequent regions of loss, suggesting the presence of novel tumour suppressor genes. Deletions of one copy of the RB and TP53 genes are less frequent as are mutations of the TP53 gene, and accumulating evidence suggests the presence of an additional tumour suppressor gene on chromosome 17p, which is frequently inactivated in prostate cancer. Alterations in the E-cadherin/alpha catenin mediated cell-cell adhesion mechanism appear to be present in almost half of all prostate cancers and may be critical to the acquisition of metastatic potential of aggressive prostate cancers. Finally, altered DNA methylation patterns have been found in the majority of prostate cancers examined, suggesting widespread alterations in methylation modulated gene expression. The presence of multiple changes in these tumours is consistent with the multistep nature of the transformation process. Finally, efforts to identify prostate cancer susceptibility loci are under way, which may elucidate critical early events in prostatic carcinogenesis.
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PMID:Molecular biology of prostate cancer progression. 762 57

The ultimate stage of carcinogenesis in both human and mouse epithelial cells is the ability to invade surrounding tissues and metastasize to distant sites. In mouse skin tumours, the development of the invasive, spindle cell phenotype is associated with an imbalance of alleles on mouse chromosome 7, including the H-ras gene. In previous work, we have described clonally related squamous and spindle cell lines from the same primary tumour which differed substantially in morphology and behaviour, but showed the same series of mutations in H-ras and p53 genes. One of the events which takes place during this transition is disruption of cell-cell contacts, possibly due to the induced expression of metalloproteinases such as stromelysin-1 and disappearance of the cell adhesion molecule E-cadherin. Parallel studies using somatic cell hybrids have shown that the spindle cell phenotype is recessive in hybrids between squamous and spindle cells. We propose that an important epidermal differentiation-controlling gene is lost during the spindle cell transition.
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PMID:Molecular mechanisms of invasion and metastasis during mouse skin tumour progression. 765 34

Squamous carcinomas of both human and rodent origin can undergo a transition to a more invasive, metastatic phenotype involving reorganization of the cytoskeleton, loss of cell adhesion molecules such as E-cadherin and acquisition of a fibroblastoid or spindle cell morphology. We have developed a series of cell lines from mouse skin tumors which represent different stages of carcinogenesis, including benign papillomas, and clonally related squamous and spindle carcinomas derived from the same primary tumor. Some spindle cells continue to express keratins, but with a poorly organized keratin filament network, whereas in others no keratin expression is detectable. All of the spindle cells lack expression of the cell adhesion molecule E-cadherin and the desmosomal component desmoplakin. Loss of these cell surface proteins therefore appears to precede the destabilization of the keratin network. At the genetic level, it is not known whether such changes involve activation of dominantly acting oncogenes or loss of a suppressor function which controls epithelial differentiation. To examine this question, we have carried out a series of fusion experiments between a highly malignant mouse skin spindle cell carcinoma and cell lines derived from premalignant or malignant mouse skin tumors, including both squamous and spindle carcinoma variants. The results show that the spindle cell phenotype as determined by cell morphology and lack of expression of keratin, E-cadherin, and desmoplakin proteins, is recessive in all hybrids with squamous cells. The hybrids expressed all of these differentiation markers, and showed suppression of tumorigenicity to a variable level dependent upon the tumorigenic properties of the less malignant fusion partner. Our results suggest that acquisition of the spindle cell phenotype involves functional loss of a gene(s) which controls epithelial differentiation.
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PMID:The conversion of mouse skin squamous cell carcinomas to spindle cell carcinomas is a recessive event. 768 80

To elucidate what changes in the expression of gap junction proteins (connexins) occur at what stages during multistage mouse skin carcinogenesis in vivo, we immunohistochemically and morphometrically analyzed the expression of connexin 26 (Cx26) and connexin 43 (Cx43) in papillomas, well-, moderately- and poorly-differentiated squamous cell carcinomas, as well as in squamous cell carcinomas at invasion sites and those metastasized into lymph nodes in female CD-1 mice as a result of treatment with dimethylbenz[a]anthracene and 12-O-tetradecanoylphorbol-13-acetate. In papillomas, no clear reduction of the two connexins was observed; however, Cx26 and Cx43 were frequently co-localized in the same gap junction plaques, whereas the two kinds of Cxs were differentially expressed in normal and surrounding non-tumorous epidermis. In squamous cell carcinomas, the expression of both Cx26 and Cx43 significantly decreased compared with surrounding non-tumorous epidermis and papillomas. The Western blot analysis confirmed that both Cx26 and Cx43 proteins were reduced in squamous cell carcinomas compared with papillomas. Furthermore, the expression of Cx26 was reduced as cancer cells became morphologically less differentiated, while that of Cx43 did not change. Squamous cell carcinomas at invasive sites showed clear reduction of Cx26 and Cx43. In squamous cell carcinomas metastasized into lymph nodes, Cx26 was expressed, but few carcinoma cells expressed Cx43. The localization of E-cadherin on the plasma membrane between cancer cells was maintained even at invasive and metastatic sites. Our data suggest that quantitative and qualitative changes in connexin expression are associated with tumor progression, including the loss of differentiation, and invasion and metastasis, during multistage mouse skin carcinogenesis.
Carcinogenesis 1995 Jun
PMID:Aberrant expression of gap junction proteins (connexins) is associated with tumor progression during multistage mouse skin carcinogenesis in vivo. 778 45


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