Karyotypic instability, including numerical and structural chromosomal aberrations, represents a distinct feature of multiple myeloma (MM). 40-50% of patients displayed hyperdiploidy, defined by recurrent trisomies of non-random chromosomes. To characterize hyperdiploid (H) and nonhyperdiploid (NH) MM molecularly, we analyzed the gene expression profiles of 66 primary tumors, and used FISH to investigate the major chromosomal alterations. The differential expression of 225 genes mainly involved in protein biosynthesis, transcriptional machinery and oxidative phosphorylation distinguished the 28 H-MM from the 38 NH-MM cases. The 204 upregulated genes in H-MM mapped mainly to the chromosomes involved in hyperdiploidy, and the29% up-regulated genes in NH-MM mapped to 16q. The identified transcriptional fingerprint was robustly validated on a publicly available gene expression dataset of 64 MM cases; and the global expression modulation of regions on the chromosomes involved in hyperdiploidy was verified using a self-developed non-parametric statistical method. We showed that H-MM could be further divided into two distinct molecular and transcriptional entities, characterized by the presence of trisomy 11 and 1q-extracopies/chromosome 13 deletion, respectively. Our data reinforce the importance of combining molecular cytogenetics and gene expression profiling to define a genomic framework for the study of MM pathogenesis and clinical management.
Upregulation of translational machinery and distinct genetic subgroups characterise hyperdiploidy in multiple myeloma.
Sex
View SamplesA SNP microarray and FISH-based procedure to detect allelic imbalances in multiple myeloma: an integrated genomics approach reveals a wide dosage effect on gene and microRNA expression
A SNP microarray and FISH-based procedure to detect allelic imbalances in multiple myeloma: an integrated genomics approach reveals a wide gene dosage effect.
Specimen part, Disease
View SamplesMultiple myeloma (MM) is characterized by marked genomic instability. Beyond structural rearrangements, a relevant role in its biology is represented by allelic imbalances leading to significant variations in ploidy status. To better elucidate the genomic complexity of MM, we analyzed a panel of 45 patients using combined FISH and microarray approaches. Using a self-developed procedure to infer exact local copy numbers for each sample, we identified a significant fraction of patients showing marked aneuploidy. A conventional clustering analysis showed that aneuploidy, chromosome 1 alterations, hyperdiploidy and recursive deletions at 1p and chromosomes 13, 14 and 22 were the main aberrations driving samples grouping. Then, we integrated mapping information with gene and microRNAs expression profiles: a multiclass analysis of the identified clusters showed a marked gene-dosage effect, particularly concerning 1q transcripts, also confirmed by correlating gene expression levels and local copy number alterations. A wide dosage effect affected also microRNAs, indicating that structural abnormalities in MM closely reflect in their expression imbalances. Finally, we identified several loci in which genes and microRNAs expression correlated with loss-of-heterozygosity occurrence. Our results provide insights into the composite network linking genome structure and gene/microRNA transcriptional features in MM.
A SNP microarray and FISH-based procedure to detect allelic imbalances in multiple myeloma: an integrated genomics approach reveals a wide gene dosage effect.
Specimen part, Disease
View SamplesBackground and objective: The chromosome 13 deletion (del(13)) represents one of the most frequent chromosomal alterations in multiple myeloma (MM). del(13) is associated with an unfavorable prognosis, although there is an increasing agreement that its prognostic relevance has to be related to the ploidy status and the presence of different chromosomal translocations. This study is aimed at providing a comprehensive analysis of the transcriptional features of del(13) in MM. Design and methods: Highly purified plasma cells from 80 newly diagnosed MM patients were characterized by means of FISH and high-density oligonucleotide microarray for gene expression profiling and chromosomal alterations. Results: We identified 67 differentially expressed genes in the del(13)+ and del(13)- groups, all of which downregulated in the del(13)+ cases: 44 mapped along the whole chromosome 13, seven on chromosome 11 and three on chromosome 19. Functional analyses of the selected genes indicated their involvement in protein biosynthesis, ubiquitination and transcriptional regulation. An integrative genomic approach based on regional analyses of the gene expression data identified distinct chromosomal regions whose global expression modulation could differentiate del(13)+, in particular the upregulation of 1q21-1q42 and the downregulation of 19p and almost the entire chromosome 11. FISH analyses confirmed the close relationship between del(13)+ and the presence of extracopies of 1q21-1q42 (P=6x10-4) or the absence of chromosome 11 and 19 trisomy (P=5x10-4). Interpretation and conclusions: Our results indicate that distinct types of chromosomal aberrations are closely related to the transcriptional profiles of del(13)+, suggesting that the contribution of del(13) on the malignancy should be considered together with associated abnormalities.
Integrative genomic analysis reveals distinct transcriptional and genetic features associated with chromosome 13 deletion in multiple myeloma.
Sex
View SamplesIn order to investigate the patterns of genetic lesions in a panel of 23 Human Multiple Myeloma Cell Lines (HMCLs), we made a genomic integrative analysis involving FISH and both gene expression and genome-wide profiling approaches. The expression profiles of the genes targeted by the main IGH translocations showed that the WHSC1/MMSET gene involved in t(4;14)(p16;q32) was expressed at different levels in all of the HMCLs, and that the expression of the MAF gene was not restricted to the HMCLs carrying t(14;16)(q32;q23). Supervised analyses identified a limited number of genes specifically associated with t(4;14) and involved in different biological processes. The signature related to MAF/MAFB expression included the known MAF target genes CCND2 and ITGB7, as well as genes controlling cell shape and cell adhesion. Genomewide DNA profiling allowed the identification of a gain on chromosome arm 1q in 88% of the analyzed cell lines, together with recurrent gains on 8q, 18q, 7q and 20q; the most frequent deletions affected 1p, 13q, 17p and 14q; and almost all of the cell lines presented LOH on chromosome 13. Two hundred and twenty-two genes were found to be simultaneously overexpressed and amplified in our panel, including the BCL2 locus at 18q21.33. Our data further support the evidence of the genomic complexity of multiple myeloma and reinforce the role of an integrated genomic approach in improving our understanding of the molecular pathogenesis of the disease.
Molecular characterization of human multiple myeloma cell lines by integrative genomics: insights into the biology of the disease.
No sample metadata fields
View SamplesThis series of microarray experiments contains the gene expression profiles of purified plasma cells (PCs) obtained from 7 monoclonal gammopathy of undetermined significance (MGUS), 39 newly diagnosed multiple myeloma (MM) and 6 plasma-cell leukaemia (PCL) patients. PCs were purified from bone marrow Seriess, after red blood cell lysis with 0.86% ammonium chloride, using CD138 immunomagnetic microbeads. The purity of the positively selected PCs was assessed by morphology and flow cytometry and was > 90% in all cases. 5 micrograms of total RNA was processed and hybridized to the Affymetrix HG-U133A chip following the manufacturer's instructions. After scanning, the images were processed using Affymetrix MicroArray Suite (MAS) 5.0 software to generate gene expression intensity values. Arrays normalization was performed using MAS 5.0 "global scaling" procedure, which normalizes the signals of different experiments to the same target intensity (TGT=100).
Gene expression profiling of plasma cell dyscrasias reveals molecular patterns associated with distinct IGH translocations in multiple myeloma.
No sample metadata fields
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Brown Adipose YY1 Deficiency Activates Expression of Secreted Proteins Linked to Energy Expenditure and Prevents Diet-Induced Obesity.
Age, Specimen part, Treatment
View SamplesAnalysis of brown adipose tissue from Yin Yang 1 (YY1) brown fat specific knockout mice fed a high fat diet for 3 months. YY1 deficiency in brown adipose tissue leads to strong thermogenic deficiency. The goal was to identify the genes controlled by YY1 responsible of brown fat defective function.
Brown Adipose YY1 Deficiency Activates Expression of Secreted Proteins Linked to Energy Expenditure and Prevents Diet-Induced Obesity.
Age, Specimen part, Treatment
View SamplesAnalysis of visceral white adipose tissue (EWAT) from Yin Yang 1 adipose-specific knockout mice exposed to cold (4C) for 4 days.
Brown Adipose YY1 Deficiency Activates Expression of Secreted Proteins Linked to Energy Expenditure and Prevents Diet-Induced Obesity.
Age, Specimen part, Treatment
View SamplesAnalysis of subcutaneous adipose tissue (IWAT) from Yin Yang 1 brown fat specific knockout mice fed a high fat diet for 2 weeks. The goal was to identify a gene signature of IWAT browning in YY1 mutant mice.
Brown Adipose YY1 Deficiency Activates Expression of Secreted Proteins Linked to Energy Expenditure and Prevents Diet-Induced Obesity.
Age, Specimen part, Treatment
View Samples