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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The TP-ras transgenic mouse line expresses an activated human T24 Ha-ras gene with a mutation in codon 12, regulated by a mouse tyrosinase promoter. The transgene is expressed in melanocytes of the skin, eyes, and brain. The mice develop cutaneous melanoma when treated with 7,12-dimethylbenz[a]anthracene. Cell lines have been generated from the cutaneous tumors and metastatic lesions. By using fluorescence in situ hybridization with mouse whole chromosome paints, the cell lines were characterized for chromosomal abnormalities. Key findings in the tumor cells included translocations of chromosome 4 and alterations in chromosome 6. One tumor cell line contained a double translocation involving chromosomes 3 and 6. To extend the results of the chromosome 4 painting, Southern analysis of the p15INK4B, p16INK4A, and p19INK4D genes was performed. Our data indicated that there were homozygous and partial allelic deletions and polymorphisms in the region of chromosome 4 containing these genes, resulting in the absence or reduced expression of the p16 product. These findings are similar to those reported for human melanoma, and the TP-ras transgenic mouse may therefore be a valuable model for studying novel strategies for melanoma prevention and treatment.
Mol Carcinog 1997 Sep
PMID:Chromosomal and genetic alterations of 7,12-dimethylbenz[a]anthracene-induced melanoma from TP-ras transgenic mice. 932 38

Progression and metastatic spread of primary cutaneous melanoma (PCM) is largely predicted by the thickness of the primary tumor. However, the accretive or proliferative pattern of growth of PCM is another aspect that might affect the prognosis. We retrieved from our histopathological files 11 superficial spreading PCM which had been documented to show an almost stable size for at least 3 years before excision. The area of the PCM at the skin surface had been measured by planimetry on the excision specimens. Histological sections were used to measure the maximum thickness of the neoplasms. A PCM volume estimate was derived by multiplying the surface area by the thickness of the tumors. In addition, the vessel area was determined beneath and outside the PCM lateral margins on Ulex europaeus agglutinin-1-stained sections using computer-assisted image analysis. Peritumoral vascularity was significantly more developed than at distance of the neoplasms. A significant negative exponential correlation was yielded between the peritumoral vascularity and the PCM volume estimate. Such vascular eclipse might be the cause of clinical PCM dormancy. However, other possible independent mechanisms are not ruled out by the present study.
Int J Mol Med 1999 Oct
PMID:Vascular retardation in dormant growth-stunted malignant melanomas. 1049 82

The phytopathogenic bacterium Clavibacter michiganensis subsp. michiganensis NCPPB382, which causes bacterial wilt and canker of tomato, harbors two plasmids, pCM1 (27.35 kb) and pCM2 (72 kb), encoding genes involved in virulence (D. Meletzus, A. Bermpohl, J. Dreier, and R. Eichenlaub, 1993, J. Bacteriol. 175:2131-2136; J. Dreier, D. Meletzus, and R. Eichenlaub, 1997, Mol. Plant-Microbe Interact. 10:195-206). The region of pCM1 carrying the endoglucanase gene celA was mapped by deletion analysis and complementation. RNA hybridization identified a 2.4-knt (kilonucleotide) transcript of the celA structural gene and the transcriptional initiation site was mapped. The celA gene encodes CelA, a protein of 78 kDa (746 amino acids) with similarity to endo-beta-1,4-glucanases of family A1 cellulases. CelA has a three-domain structure with a catalytic domain, a type IIa-like cellulose-binding domain, and a C-terminal domain. We present evidence that CelA plays a major role in pathogenicity, since wilt induction capability is obtained by endoglucanase expression in plasmid-free, nonvirulent strains and by complementation of the CelA- gene-replacement mutant CMM-H4 with the wild-type celA gene.
Mol Plant Microbe Interact 2000 Jul
PMID:The endo-beta-1,4-glucanase CelA of Clavibacter michiganensis subsp. michiganensis is a pathogenicity determinant required for induction of bacterial wilt of tomato. 1087 31

The frequent loss of both INK4a and ARF in melanoma raises the question of which INK4a-ARF gene product functions to suppress melanoma genesis in vivo. Moreover, the high incidence of INK4a-ARF inactivation in transformed melanocytes, along with the lack of p53 mutation, implies a cell type-specific role for INK4a-ARF that may not be complemented by other lesions of the RB and p53 pathways. A mouse model of cutaneous melanoma has been generated previously through the combined effects of INK4a(Delta2/3) deficiency (null for INK4a and ARF) and melanocyte-specific expression of activated RAS (tyrosinase-driven H-RAS(V12G), Tyr-RAS). In this study, we made use of this Tyr-RAS allele to determine whether activated RAS can cooperate with p53 loss in melanoma genesis, whether such melanomas are biologically comparable to those arising in INK4a(Delta2/3-/-) mice, and whether tumor-associated mutations emerge in the p16(INK4a)-RB pathway in such melanomas. Here, we report that p53 inactivation can cooperate with activated RAS to promote the development of cutaneous melanomas that are clinically indistinguishable from those arisen on the INK4a(Delta2/3) null background. Genomewide analysis of RAS-induced p53 mutant melanomas by comparative genomic hybridization and candidate gene surveys revealed alterations of key components governing RB-regulated G(1)/S transition, including c-Myc, cyclin D1, cdc25a, and p21(CIP1). Consistent with the profile of c-Myc dysregulation, the reintroduction of p16(INK4a) profoundly reduced the growth of Tyr-RAS INK4a(Delta2/3-/-) tumor cells but had no effect on tumor cells derived from Tyr-RAS p53(-/-) melanomas. Together, these data validate a role for p53 inactivation in melanomagenesis and suggest that both the RB and p53 pathways function to suppress melanocyte transformation in vivo in the mouse.
Mol Cell Biol 2001 Mar
PMID:Dual inactivation of RB and p53 pathways in RAS-induced melanomas. 1123 48

The MIP-MOD (for MOD-locus associated Major Intrinsic Protein) gene encodes an aquaporin-like product, and has been reported to be a candidate for the MOD gene which is required for the self-incompatibility response in Brassica rapa. In an antisense suppression experiment designed to investigate the role of MIP-MOD, we found that levels of MIP-MOD mRNA in the stigmas of fourteen antisense transgenics, as well as in the self-incompatible cultivar Osome (Osm), were much lower than in the stigmas of the self-incompatible S8 homozygous (S8) strain. Therefore, we analyzed the molecular structure of the MIP-MOD gene in three B. rapa strains: S8, Osm, and the self-compatible var. Yellow Sarson (YS). Nucleotide sequence analysis of the MIP-MOD genes isolated from the three strains revealed that all three encode the same amino acid sequence and that YS and Osm contain the same MIP-MOD allele, designated MIP-MOD(YS). Analysis of other self-incompatible B. rapa strains that are homozygous for the MIP-MOD(YS) allele indicated that high levels of MIP-MOD transcripts are not essential for the self-incompatibility response. Furthermore, a MOD mutant generated by gamma-irradiation was found to contain a wild-type MIP-MOD gene that is expressed at normal levels. These data suggest that MIP-MOD is not MOD itself. We suggest that this gene should be renamed MLM (for MIP gene linked to MOD).
Mol Genet Genomics 2001 May
PMID:Molecular genetic analysis of the candidate gene for MOD, a locus required for self-incompatibility in Brassica rapa. 1140 35

Melanoma is a neoplasia of dramatically increasing incidence that has a propensity to spread rapidly. Early detection is fundamental and patient management requires reliable, sensitive and reproducible staging methods, such as a single examination by planar scintigraphy or single-photon emission tomography (SPET) using a radiopharmaceutical with selectivity for melanoma tissue. Among iodobenzamides reported to possess an affinity for melanoma, a new compound, N-(2-diethylaminoethyl)-2-iodobenzamide (BZA(2)), was selected for a clinical trial in view of its pharmacokinetic experimental profile in melanoma-bearing mice. Planar whole-body scintigraphy using (123)I-BZA(2) was performed in 25 patients with histologically proven cutaneous melanoma. Performance was evaluated in two groups of patients with one or more documented secondary lesions ( n=13) or with no known secondary lesions ( n=12), and results were compared with those of conventional investigation techniques. No adverse clinical or biological events were recorded. Lesions were imaged by increased tracer uptake, and good quality images were obtained 4 h after administration. After a follow-up of more than 1 year, the overall results of (123)I-BZA(2) scintigraphy on a per patient basis showed a sensitivity of 100%, a specificity of 95%, a positive predictive value of 86% and a negative predictive value of 100%. The proven secondary lesions were imaged with a sensitivity of 100% and a specificity of 91%. In seven patients with suspected metastases, the absence of (123)I-BZA(2) uptake was confirmed as true negative, and in one patient without suspected metastases, (123)I-BZA(2) scintigraphy revealed a gastric lesion. Hence eight diagnoses would have been modified by (123)I-BZA(2) scintigraphy data. (123)I-BZA(2) allowed discrimination between benign and malignant lesions and, in the case of malignancies, between those of melanomatous origin and others. This compound, which is selective for melanoma tissue, appears promising for the staging and restaging of melanoma.
Eur J Nucl Med Mol Imaging 2002 Nov
PMID:123I-N-(2-diethylaminoethyl)-2-iodobenzamide: a potential imaging agent for cutaneous melanoma staging. 1239 67

The aim of this study was to evaluate the Melanoblastoma-bearing Libechov Minipigs (MeLiM) as an animal model of melanoma for in vivo imaging. Serial whole-body 2-deoxy-2-[(18)F]fluoro- d-glucose positron emission tomography (FDG PET) scans were conducted on five MeLiM. In order to explore different clinical stages of the tumoural lesions, each animal was scanned two to four times, at intervals of 30-155 days. PET images were analysed by a semiquantitative method based on the tumour to muscle metabolic ratio. Histology was performed on biopsies taken between or after the scans and the histological grading of the tumours was compared with the FDG uptake. The overall sensitivity of FDG PET for the detection of cutaneous melanoma was 75%; 62.5% of involved lymph nodes were positive. Sensitivity was better for tumours with vertical growth than for flat lesions. FDG PET did not detect tumours with epidermal involvement only, nor did it detect small metastatic foci. The metabolic ratio was correlated with the evolution of the melanoma. FDG PET is effective in the staging of cutaneous melanoma and the follow-up of tumoural extension and regression in Melanoblastoma-bearing Libechov Minipigs. The results obtained in this animal model correlate well with those described in human melanoma. Accordingly, this model may be useful in testing new tracers specific for melanoma and in helping to detect molecules expressed early during tumoural regression.
Eur J Nucl Med Mol Imaging 2003 Jun
PMID:A new animal model for the imaging of melanoma: correlation of FDG PET with clinical outcome, macroscopic aspect and histological classification in Melanoblastoma-bearing Libechov Minipigs. 1268 88

Currently, melanoma remains a surgical disease since early detection and excision of thin melanomas offers the best chance of a cure. Despite intensive clinical investigation, no effective systemic therapies exist for metastatic melanoma. Sentinel lymph node biopsy has greatly aided the staging and prognostic evaluation of primary cutaneous melanoma, however, approximately a third of patients diagnosed with metastatic melanomas present without prior regional lymph node involvement. Additional prognostic biomarkers exist which help determine the risk of advanced melanoma but the accuracy for each current marker is less than 100%. A greater understanding of the biology of melanomas and the development of new methods to identify patients with early (subclinical) metastatic disease may allow for selective and more effective therapy for patients at-risk for advanced disease. In this paper, current and novel potentially more accurate biomarkers for the staging and prognostic evaluation of melanoma patients, and for the detection of subclinical metastases are reviewed.
Expert Rev Mol Diagn 2003 May
PMID:Biomarkers in melanoma: staging, prognosis and detection of early metastases. 1277 6

The incidence of cutaneous malignant melanoma in the United States has increased more than any other cancer in recent years. Chemotherapy for metastatic melanoma is disappointing, there being anecdotal cases of complete remission. Dacarbazine (DTIC) is considered the gold standard for treatment, having a response rate of 15-20%, but most responses are not sustained. The mechanisms for the increased chemotherapeutic resistance of melanoma are unclear. The objective of this study was to determine the mechanisms by which melanoma cells escape the cytotoxic effect of DTIC. Here, we show that DTIC induced interleukin (IL)-8 and vascular endothelial growth factor (VEGF) protein overexpression and secretion via transcriptional up-regulation in the two melanoma cell lines SB-2 and MeWo. Luciferase activity driven by the IL-8 and VEGF promoters was up-regulated by 1.5-2- and 1.6-3.5-fold, respectively, in the SB2 and MeWo melanoma cell lines. The mitogen-activated protein kinase signal transduction pathway seemed to regulate at least partially the activation of IL-8, whereas it was not involved in VEGF promoter regulation. Electrophoretic mobility shift analysis analyses have revealed an increase in binding activity of activator protein 1 (c-Jun) and nuclear factor-kappaB after DTIC treatment for both melanoma cell lines. Metastatic melanoma cell lines secreting high levels of IL-8 and VEGF were more resistant to DTIC than early primary melanomas secreting low levels of the cytokines. In addition, transfection of the primary cutaneous melanoma SB-2 cells with the IL-8 gene rendered them resistant to the cytotoxic effect of the drug, whereas the addition of IL-8-neutralizing antibody to metastatic melanoma cells lowered their sensitivity to DTIC. Taken together, our data demonstrate that DTIC can cause melanoma cells to secrete IL-8 and VEGF, which might render them resistant to the cytotoxic effects of the drug. We propose that combination treatment with anti-VEGF/IL-8 agents may potentiate the therapeutic effects of DTIC.
Mol Cancer Ther 2003 Aug
PMID:Dacarbazine causes transcriptional up-regulation of interleukin 8 and vascular endothelial growth factor in melanoma cells: a possible escape mechanism from chemotherapy. 1502 59

Melanoma is a deadly cancer due to its propensity to metastasize. Pharmacological inhibition of cell motility may benefit patients with cutaneous melanoma by preventing metastasis to internal organs. The Rho GTPases are signaling molecules that drive metastasis by controlling cell motility. We found RhoC to be expressed in clinical melanoma specimens and hypothesized that inhibiting its activation might prevent metastasis. Some Rho proteins, such as RhoC, depend on posttranslational geranylgeranylation for biological activity. We investigated the effect that Atorvastatin, a 3-hydroxy 3-methylglutaryl CoA (HMG-CoA) reductase inhibitor that prevents Rho geranylgeranylation, had on subcellular localization and activity of Rho proteins as well as the metastatic ability of melanoma cells. Atorvastatin inhibited Rho activation and reverted the metastatic phenotype of human melanoma cells in vitro. Moreover, Atorvastatin, at plasma levels comparable to those used to treat of hypercholesterolemia, inhibited in vivo metastasis of melanoma cells overexpressing RhoC. These results support further examination of statins for primary prophylaxis of melanoma metastasis.
Mol Cancer Ther 2003 Oct
PMID:Atorvastatin prevents RhoC isoprenylation, invasion, and metastasis in human melanoma cells. 1457 59


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