Anaplastic large cell lymphomas (ALCLs) represent a subset of lymphomas in which the anaplastic lymphoma kinase (ALK) gene is frequently fused to the nucleophosmin (NPM) gene. We previously demonstrated that the constitutive phosphorylation of ALK chimeric proteins is sufficient to induce cellular transformation in vitro and in vivo and that ALK activity is strictly required for the survival of ALK-positive ALCL cells. To elucidate the signaling pathways required for ALK-mediated transformation and tumor maintenance, we analyzed the transcriptomes of multiple ALK-positive ALCL cell lines, abrogating their ALK-mediated signaling by inducible ALK RNA interference (RNAi) or with potent and cell-permeable ALK inhibitors. Transcripts derived from the gene expression profiling (GEP) analysis uncovered a reproducible signature, which included a novel group of ALK-regulated genes. Functional RNAi screening on a set of these ALK transcriptional targets revealed that the transcription factor C/EBPbeta and the antiapoptotic protein BCL2A1 are absolutely necessary to induce cell transformation and/or to sustain the growth and survival of ALK-positive ALCL cells. Thus, we proved that an experimentally controlled and functionally validated GEP analysis represents a powerful tool to identify novel pathogenetic networks and validate biologically suitable target genes for therapeutic interventions.
Pubmed ID: 17111047 RIS Download
Mesh terms: Animals | Apoptosis | CCAAT-Enhancer-Binding Protein-beta | Cell Cycle | Cell Line | Cell Survival | Cell Transformation, Neoplastic | Flow Cytometry | Gene Expression Profiling | Humans | Lymphoma, Large B-Cell, Diffuse | Mice | Minor Histocompatibility Antigens | Neoplasms | Nuclear Proteins | Oligonucleotide Array Sequence Analysis | Phosphorylation | Protein-Tyrosine Kinases | Proto-Oncogene Proteins c-bcl-2 | RNA Interference | Receptor Protein-Tyrosine Kinases | Reverse Transcriptase Polymerase Chain Reaction | STAT3 Transcription Factor | Signal Transduction
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