ABSTRACT
Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. To identify novel candidates for targeted therapy, we performed a comprehensive transcriptome analysis identifying MondoA (MLXIP) - a transcription factor regulating glycolysis - to be overexpressed in ALL compared to normal tissues. Using microarray-profiling, gene-set enrichment analysis, RNA interference and functional assays we show that MondoA overexpression increases glucose catabolism and maintains a more immature phenotype, which is associated with enhanced survival and clonogenicity of leukemia cells. These data point to an important contribution of MondoA to leukemia aggressiveness and make MondoA a potential candidate for targeted treatment of ALL.
Subject(s)
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/genetics , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/physiology , Cell Differentiation/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology , Apoptosis/drug effects , Apoptosis/genetics , Apoptosis/physiology , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/metabolism , Cell Differentiation/drug effects , Cell Survival/drug effects , Cell Survival/genetics , Drug Evaluation, Preclinical , Gene Expression Profiling , Gene Expression Regulation, Leukemic/drug effects , Hep G2 Cells , Humans , Jurkat Cells , Microarray Analysis , Neoplasm Invasiveness , Precursor Cell Lymphoblastic Leukemia-Lymphoma/physiopathology , RNA, Small Interfering/pharmacology , Tumor Cells, Cultured , Up-Regulation/drug effects , Up-Regulation/geneticsABSTRACT
In this study, microarray analysis was used to identify tumour-related genes that were down regulated in lung carcinoma. The promoter sequences of the identified genes were analysed for methylation patterns. In lung cancer cell lines, CpG island methylation was frequently detected for TIMP4 (64%), SOX18 (73%), EGF-like domain 7 (56%), CD105 (71%), SEMA2 (55%), RASSF1A (71%), p16 (56%) SLIT2 (100%) and TIMP3 (29%). Methylation was however rarely observed in cell lines for SLIT3 (18%) and DLC1 (18%). In primary lung tumours, methylation of TIMP4 (94%), SOX18 (100%), EGF-like domain 7 (100%), CD105 (69%), SEMA2 (93%), DLC1 (61%), RASSF1A (44%), p16 (47%), SLIT2 (100%) and TIMP3 (13%) was also detected. Methylation of several CpG islands was frequently found in normal lung tissue of cancer patients and this may have been attributed to epigenetic field defect and/or infiltrating tumour cells. Interestingly, inactivation of RASSF1A and p16 correlated well with an extended smoking habit (P=0.02), and exposure to asbestos (P=0.017) or squamous cell carcinoma (P=0.011), respectively. These results have identified genes whose aberrant promoter methylation could play a crucial role in the malignancy of lung carcinoma.
Subject(s)
Carcinoma, Non-Small-Cell Lung/genetics , CpG Islands/genetics , DNA Methylation , Genes, Tumor Suppressor , Lung Neoplasms/genetics , Aged , Cell Line, Tumor , Female , Humans , Male , Microarray Analysis , RNA, Neoplasm/analysis , Reverse Transcriptase Polymerase Chain Reaction , Tissue Inhibitor of Metalloproteinases/genetics , Tumor Suppressor Proteins/genetics , Tissue Inhibitor of Metalloproteinase-4ABSTRACT
Ewing family tumors (EFTs) are small round blue cell tumors that show features of neuroectodermal differentiation. However, the histogenetic origin of EFTs is still a matter of debate. We used high-density DNA microarrays for the identification of EFT-specific gene expression profiles in comparison with normal tissues of diverse origin. We identified 37 genes that are up-regulated in EFTs compared with normal tissues and validated expression of these genes in EFTs by both conventional and quantitative reverse transcription-polymerase chain reaction. The expression pattern of EFT-associated genes in normal tissues indicated a high similarity between EFTs and fetal and neuronal as well as endothelial tissues and supports the concept that a primitive neural crest-derived progenitor at the transition to mesenchymal and endothelial differentiation is transformed in EFTs. EFT-associated genes could be used for molecular discrimination between EFTs and other small round blue cell tumors and clearly identified a cell line (SK-N-MC) that was initially established as neuroblastoma as being an EFT. Ectopic expression of the EFT-specific EWS-FLI1 fusion protein in human embryonic kidney (HEK293) cells was not sufficient to induce the complete EFT-specific gene expression signature, suggesting that the EFT-specific gene expression profile is not just a consequence of EWS-FLI1 expression but depends on the histogenetic background of the EFT stem cell.
