Expression .CEL files from Affymetrix HG-U133A 2.0 arrays using DNA from 14 human cell lines derived from metastasized melanoma
Differences in global gene expression in melanoma cell lines with and without homozygous deletion of the CDKN2A locus genes.
Specimen part, Cell line
View SamplesThe molecular biology of metastatic potential in melanoma has been studied many times previously and changes in the expression of many genes have been linked to metastatic behaviour. What is lacking is a systematic characterization of the regulatory relationships between genes whose expression is related to metastatic potential. Such a characterization would produce a molecular taxonomy for melanoma which could feasibly be used to identify epigenetic mechanisms behind changes in metastatic behaviour. To achieve this we carried out three separate DNA microarray analyses on a total of 86 cultures of melanoma. Significantly, multiple testing correlation revealed that previous reports describing correlations of gene expression with activating mutations in BRAF or NRAS were incorrect and that no gene expression patterns correlate with the mutation status of these MAPK pathway components. Instead, we identified three different sample cohorts (A, B and C) and found that these cohorts represent melanoma groups of differing metastatic potential. Cohorts A and B were susceptible to TGFbeta-mediated inhibition of proliferation and had low motility. Cohort C was resistant to TGFb and demonstrated high motility. Meta-analysis of the data against previous studies linking gene expression and phenotype confirmed that cohorts A and C represent transcription signatures of weakly and strongly metastatic melanomas, respectively. Gene expression co-regulation suggested that signalling via TGFbeta-type and Wnt pathways underwent considerable change between cohorts. These results suggest a model for the transition from weakly to strongly metastatic melanomas in which TGFbeta-type signalling upregulates genes expressing vasculogenic/extracellular matrix remodeling factors and Wnt signal inhibitors, coinciding with a downregulation of genes downstream of Wnt signalling.
Metastatic potential of melanomas defined by specific gene expression profiles with no BRAF signature.
Sex, Age, Specimen part
View SamplesThe molecular biology of metastatic potential in melanoma has been studied many times previously and changes in the expression of many genes have been linked to metastatic behaviour. What is lacking is a systematic characterization of the regulatory relationships between genes whose expression is related to metastatic potential. Such a characterization would produce a molecular taxonomy for melanoma which could feasibly be used to identify epigenetic mechanisms behind changes in metastatic behaviour. To achieve this we carried out three separate DNA microarray analyses on a total of 86 cultures of melanoma. Significantly, multiple testing correlation revealed that previous reports describing correlations of gene expression with activating mutations in BRAF or NRAS were incorrect and that no gene expression patterns correlate with the mutation status of these MAPK pathway components. Instead, we identified three different sample cohorts (A, B and C) and found that these cohorts represent melanoma groups of differing metastatic potential. Cohorts A and B were susceptible to TGFbeta-mediated inhibition of proliferation and had low motility. Cohort C was resistant to TGFb and demonstrated high motility. Meta-analysis of the data against previous studies linking gene expression and phenotype confirmed that cohorts A and C represent transcription signatures of weakly and strongly metastatic melanomas, respectively. Gene expression co-regulation suggested that signalling via TGFbeta-type and Wnt pathways underwent considerable change between cohorts. These results suggest a model for the transition from weakly to strongly metastatic melanomas in which TGFbeta-type signalling upregulates genes expressing vasculogenic/extracellular matrix remodeling factors and Wnt signal inhibitors, coinciding with a downregulation of genes downstream of Wnt signalling.
Metastatic potential of melanomas defined by specific gene expression profiles with no BRAF signature.
No sample metadata fields
View SamplesWe address the function of HEXIM, an inhibitor of the general transcriptional elongation regulator P-TEFb which regulates the transcriptional status of many developmental genes, during Drosophila development. We showed that HEXIM knockdown mutants display organs development failure. In the wing disc, it induces apoptosis and affects Hh signaling. The continuous death of proliferative cells is compensated by apoptosis-induced cell proliferation, in a manner similar to that of differentiated cells, together with high levels of Hh and Ci. We completed this analysis with microarrays to characterize the molecular phenotype of HEXIM knockdown during eye differentiation.
Functional Interaction between HEXIM and Hedgehog Signaling during Drosophila Wing Development.
Specimen part
View SamplesWe showed that a large number of genes and exons were deregulated in colorectal adenomas in comparison with colorectal normal mucosa.
A gene expression and pre-mRNA splicing signature that marks the adenoma-adenocarcinoma progression in colorectal cancer.
Specimen part
View Samples