Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

H-ras-transformed NIH3T3 cells that overexpressed a human melanoma-associated antigen ME491 (44-3H) were generated by transfection with the cloned ME491 antigen gene followed by a 'panning' selection, and effects of the antigen overexpression on H-ras-mediated malignant phenotypes were studied. Although in vitro growth properties of the 44-3H overexpresser cells, both anchorage-dependent and -independent, were practically the same as those of the 44-1C control cells, 44-3H cells exhibited less malignant phenotypes in athymic nude mice (in vivo), i.e. decreased tumourigenicity after subcutaneous inoculation and prolonged survival time after intraperitoneal inoculation, compared with 44-1C cells. These results suggested that overexpression of ME491 antigen partially suppressed malignant phenotypes of H-ras-transformed NIH3T3 cells in athymic nude mice through co-operating with a factor(s) or mechanism(s) that exist in vivo but not in vitro. Thus, ME491 antigen might act as a tumour suppressor under some circumstances.
Melanoma Res
PMID:Overexpression of the human melanoma-associated antigen ME491 partially suppresses in vivo malignant phenotypes of H-ras-transformed NIH3T3 cells in athymic nude mice. 182 25

Mutations of the p53 tumour suppressor gene are common to many human malignancies. Although increased p53 expression has been observed in cutaneous malignant melanoma, mutations of the p53 gene appear to be infrequent. We examined 140 benign and malignant paraffin-embedded melanocytic lesions for p53 protein expression by immunohistochemistry, using the monoclonal anti-p53 antibody DO-7 and a microwave method of antigen retrieval. Fifteen naevi and 25 melanomas were further analysed for p53 mutations within exons 5-8 of the p53 gene. DNA was extracted from paraffin sections and screening for mutations was carried out using PCR-SSCP. We demonstrated p53 protein expression in 33% of naevi (17 out of 51), 35% of primary melanomas (20 out of 58), and 70% of metastatic lesions (15 out of 21). p53 expression in benign lesions was weaker than in malignant lesions in intensity and percentage of cells staining. p53 protein expression in melanomas increased in intensity and percentage of cells staining with tumour progression. In 25% (three out of 12) of metastatic melanomas p53 mutations were detected by PCR-SSCP and increased expression of p53 protein was observed in these tumours. p53 gene mutations were not detected in any benign melanocytic lesions. We demonstrate that antigen retrieval techniques increase p53 immunoreactivity in paraffin embedded melanocytic tissues. p53 protein expression in melanomas increases with depth of tumour invasion. As p53 gene mutations occur infrequently in malignant melanoma, other mechanisms are proposed to influence p53 protein expression in melanocytic lesions.
Melanoma Res 1995 Apr
PMID:p53 gene mutation and expression in naevi and melanomas. 762 Mar 45

Combined multi-point linkage analysis in seven Dutch families with FAMMM syndrome confirmed the location of a melanoma susceptibility (MLM) gene in the 9p21 area. The occurrence of a shared high-risk haplotype in six of the families strongly suggests a founder effect in the Leiden region. No indication for locus heterogeneity was observed. Recently, the CDKN2 (p16) gene, an important regulator of the cell cycle, was isolated from the 9p21 region. A 19-bp germline deletion in the CDKN2 gene was detected in the high-risk haplotype, suggesting CDKN2 to be identical to MLM. Loss of heterozygosity studies in melanoma and pancreatic carcinoma from gene carriers strongly support the view that CDKN2 is a general tumour suppressor gene predisposing not only to melanoma but also to other malignancies. Interestingly, the occurrence of apparent clinical FAMMM cases with melanoma but without the high-risk deletion haplotype suggests the necessity of additional (naevus) genes to explain the complete FAMMM phenotype.
Melanoma Res 1995 Jun
PMID:CDKN2 explains part of the clinical phenotype in Dutch familial atypical multiple-mole melanoma (FAMMM) syndrome families. 764 May 18

Melanoma may cluster in families with 'family cancer syndromes' in which there is a predisposition to a variety of different tumours. Other families seem vulnerable to melanoma alone. In the majority of these families, the propensity to melanoma is associated with the presence of abnormal melanocytic naevi, the so-called atypical mole syndrome (AMS) phenotype. However, in a smaller number of families, individuals are susceptible to melanoma but have normal naevi. There appears, therefore, to be clinical (and probably genetic) heterogeneity. Segregation analysis does not support a predisposition by single dominant gene as an explanation for the AMS/melanoma syndrome. To date, a single gene which is clearly important for susceptibility to melanoma has not been identified. Karyotypic studies of melanoma tumours have pointed to chromosomes 1, 6, 7, 9 and 10 as possible sites for melanoma related genes. Loss of heterozygosity studies have suggested that chromosome 9 may carry a tumour suppressor gene important in familial disease, and linkage studies appear to confirm this. It is not yet clear, however, what percentage of familial melanoma is attributable to this gene. A more longstanding suggestion that a gene on chromosome 1 may be important has not been confirmed, but a chromosome/gene may be responsible for susceptibility in a small subset of melanoma families. Even within AMS families, there is a lack of concordance between the AMS phenotype and susceptibility to melanoma. This might be explained either by the effects of modifying genes, or the environment.
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PMID:Genetics of melanoma. 798 47

A gene for familial melanoma (MLM) has been mapped to 9p22-p13 by linkage analysis using simple tandem repeat polymorphisms (STRPs) at the IFNA and D9S126 loci. This localization is consistent with the finding of homozygous deletions of these markers in DNA from two melanoma cell lines, which suggest that the locus has the properties of a tumour suppressor gene. In an attempt to further define the position of the MLM locus we have typed 10 STRPs from the short arm of chromosome 9 in 15 Australian melanoma kindreds. Extended haplotype analysis of these markers and identification of recombinants in our pedigrees indicate that the MLM gene is flanked on the centromeric side by D9S169 and on the telomeric side by D9S156. These results limit the location of the MLM locus to an interval of about 16 centimorgans.
Melanoma Res 1994 Feb
PMID:Haplotype analysis limits the position of the familial melanoma locus on 9p to the D9S169-D9S156 interval. 803 15

Recent evidence has suggested the presence of a malignant melanoma (MM)-related gene on human chromosome 9p21, the location of the putative tumour suppressor genes p15 and p16. DNA from patients with familial MM, from MM cell lines and sporadic MM cases has been examined for coding region and splice junction mutations of the p16 gene, but expression studies of both genes from the same cells have not been reported. We used the polymerase chain reaction to analyse p16 and p15 expression in 23 MM cell lines. Fourteen lines (61%) did not express either gene. Six (26%) expressed p16 and eight (35%) expressed p15. Expression patterns were concordant in most cases (83%), but one line (4%) expressed only p16 and three lines (13%) expressed only p15. These data suggest that loss of function of these genes, as judged by expression, may be higher than predicted by previous DNA-based studies. The lack of complete concordance between p15 and p16 expression implies that the genes are not functionally redundant and that loss of either gene may be important in the pathogenesis of MM.
Melanoma Res 1996 Aug
PMID:Expression of the tumour suppressor genes p15 and p16 in malignant melanoma. 887 47

Inactivation of p16 tumour suppressor gene has been reported frequently in melanoma cell lines, and mutations have been detected in familial melanoma kindreds. The aim of this study was to assess the role of p16 inactivation in melanocytic progression by measuring the level of p16 protein in a range of sporadic, benign and malignant melanocytic lesions. Using dual parameter flow cytometry, p16 protein expression was measured in 30 benign melanocytic naevi, 38 primary and 51 metastatic melanomas. A high level of p16 expression was demonstrated in benign melanocytic naevi (96% median nuclear positivity), with a significant reduction in primary melanomas (69%, P < 0.001). The median nuclear positivity of primary melanomas was significantly higher (P < 0.03) than the level of expression in metastatic lesions (median positivity 37%). A progressive loss of p16 expression was demonstrated from benign melanocytic naevi through to primary and metastatic lesions. These data suggest that loss of p16 protein expression is not only associated with the early transformation of benign lesions, but also with the later stages of malignant progression.
Melanoma Res 1998 Jun
PMID:An analysis of p16 protein expression in sporadic malignant melanoma. 966 49

A candidate tumour suppressor gene, PTEN, has recently been identified within chromosome 10q23, the locus of the Cowden syndrome/Lhermitte Duclos disease susceptibility gene. Cowden disease is an autosomal dominant cancer predisposition syndrome associated with tumours of the breast, thyroid and, less frequently, malignant melanoma. Based on the identification of mutations in sporadic breast, brain and prostate tumours, we decided to examine the potential role of PTEN in sporadic malignant melanoma. Frozen tissue from primary cutaneous melanomas (n = 23) and metastases (n = 17) were microdissected, and microsatellite markers D10S541 and D10S547, flanking the gene on both sides, were used to search for loss of heterozygosity (LOH) in the PTEN gene locus. To identify mutations within the putative tumour suppressor gene, we performed single strand conformation polymorphism (SSCP) analysis using intronic primers to amplify exons 5, 6, 7 and 8 of the PTEN gene. No LOH was detected using the polymorphic markers D10S541 and D10S547. SSCP analysis revealed no aberrant bands in the tumour specimen. Our results suggest that the PTEN gene does not play a major role in the initiation and progression of melanoma.
Melanoma Res 1998 Aug
PMID:The PTEN tumour suppressor gene and malignant melanoma. 976 4

Five human melanoma cell lines were investigated for their antioxidant activities. These metabolic data were correlated with cytogenetic analysis giving the relative numbers of chromosomes or chromosomal segments carrying the gene encoding for each enzyme. Particular attention was focused on the expression of superoxide dismutase 2 (SOD2), whose gene, located on the long arm of chromosome 6 (6q), has been proposed as a tumour suppressor gene. The activity of glutathione peroxidase (GPX), glutathione reductase (GSR) and catalase appeared to be unrelated to the relative number of 3q, 8p and 11p arms which, respectively, carry their encoding genes. GPX activity paralleled that of total SOD activity, and GSR variations followed those of GPX, suggesting possible metabolic regulation. Both the activity and the amount of SOD1 immunoreactive protein correlated with the number of chromosomes 21, suggesting a gene dosage effect. The three cell lines with deletions of the 6q arm had lower SOD2 activity and less immunoreactive protein than the two cell lines without 6q deletion. In addition, they demonstrated high thymidine kinase and thymidylate synthetase activities, which are directly linked to the cell proliferation rate. These results strengthen the hypothesis that SOD2 has a function as a tumour suppressor gene, but also suggest that the expression of other antioxidant enzymes might be altered in human melanomas.
Melanoma Res 1998 Aug
PMID:Modifications of the antioxidant enzymes in relation to chromosome imbalances in human melanoma cell lines. 976 8

Recently p73, a novel p53 homologous tumour suppressor gene, has been cloned and mapped to chromosome 1p36. Like p53, important functions of p73 in controlling the cell cycle and programmed cell death have been described. Loss of p73 has been demonstrated in neuroblastomas and its involvement in tumorigenesis has been suggested to occur in other neuroectodermal cancers. Since genetic alterations at the tumour suppressor locus 1p36 have been also identified in malignant melanomas, we investigated the expression of p73 in a panel of nine different human melanoma cell lines, 17 melanocytic naevi, 17 primary malignant melanomas and 20 metastases by reverse transcriptase polymerase chain reaction (PCR) and Southern blotting. We observed significant p73 mRNA expression in all the cell lines and tissue specimens except one benign melanocytic naevus and one melanoma metastasis. Sequencing the PCR fragments of nine melanoma cell lines derived from primary tumours and five metastases over the entire p73 DNA binding domain revealed wild-type sequences in all cases. In summary, we conclude that loss of p73 mRNA expression or mutations in the p73 DNA binding domain do not represent common genetic events involved in the pathogenesis of malignant melanomas.
Melanoma Res 1998 Dec
PMID:Loss of expression or mutations in the p73 tumour suppressor gene are not involved in the pathogenesis of malignant melanomas. 991 12


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