title: Effect of common B-RAF and N-RAS mutations on global gene expression in melanoma cell lines.
abstract: We studied global gene expression in three melanoma cell lines with the most common and potent V600E mutation in the B-RAF gene-four cell lines with a common Q61R mutation in the N-RAS gene and three cell lines with no mutations using human HG-U133A 2.0 micro-arrays with 22 277 transcripts. Data analysis using stringent criteria revealed several upregulated and downregulated genes in cell lines with B-RAF and N-RAS mutations compared with cell lines without mutations. We found 29 genes specifically upregulated and 32 genes downregulated in cell lines with B-RAF mutations, whereas 70 genes were upregulated and 39 downregulated in cell lines with N-RAS mutations; 11 genes showed overlapping upregulation and 45 downregulation. The micro-array data for nine selected genes were validated by the real-time PCR technique. Expression of a large number of genes, that encode members or regulators of the RAS/RAF/MEK/ERK pathways or are involved in metastasis or invasion, was affected in cell lines with mutations in B-RAF and N-RAS. Upregulated genes in cell lines with mutations included dual-specificity phosphatase 6 (DUSP6), sprouty 2 (SPRY2), v-akt murine thymoma viral oncogene homolog 3 (AKT3) and matrix metalloproteinase 14 (MMP14); downregulated genes included interleukin 18 (IL18), Krüppel-like factor 5 (KLF5) and inhibitor of DNA binding 2 (ID2). Our results, though carried on cell lines, provide a novel insight into the effect of mutations in the B-RAF and N-RAS genes on global gene expression in melanoma and highlight the complexity of mechanisms involved in tumour initiation and maintenance.
authors.affiliation: Division of Molecular Genetic Epidemiology, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Bloethner
authors.forename: Bowang
authors.initials: B
authors.lastname: Chen
authors.forename: Kari
authors.initials: K
authors.lastname: Hemminki
authors.forename: Jan
authors.initials: J
authors.lastname: Müller-Berghaus
authors.forename: Selma
authors.initials: S
authors.lastname: Ugurel
authors.forename: Dirk
authors.initials: D
authors.lastname: Schadendorf
authors.forename: Rajiv
authors.initials: R
authors.lastname: Kumar
mesh_terms: D004252:DNA Mutational Analysis; D015536:Down-Regulation; D020869:Gene Expression Profiling; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008545:Melanoma / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D012878:Skin Neoplasms / Q000235:genetics*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D048493:Proto-Oncogene Proteins B-raf