Dataset Information

Comparative Transcriptional Analysis of Canine and Human Diffuse Large B cell Lymphoma (DLBCL). Molecular Signatures of NF-κB Pathway Activation and Sub-Classification of Canine DLBCL.

ABSTRACT: In this study, we present the first comparison of global transcriptional changes taking place in canine lymphoma and human diffuse large B-cell lymphoma (DLBCL), with particular reference to the nuclear factor-kappaB (NF-κB) pathway. Microarray data generated from lymph nodes diagnosed with canine DLBCL and healthy lymph nodes were used for differential expression analysis, co-expression analysis and pathway analysis, and compared with analysis of publicly available microarray data from human healthy and DLBCL lymph nodes. The comparisons between species at gene level were performed by mapping the probesets in canine microarrays to orthologous genes in humans and vice versa. A considerable number of differentially expressed genes between canine lymphoma and healthy lymph node samples were also found differentially expressed between human DLBCL and healthy lymph node samples. Principal component analysis (PCA) using a literature derived 120 NF-κB target gene set mapped to 199 orthologous canine array probesets and 259 human array probesets clearly separated the healthy and cancer samples in both canine and human datasets. The analysis demonstrated that for both human and canine DLBCL there is activation of the NF-κB/p65 canonical pathway rather than the alternative pathway. This has therapeutic implications for the use of specific pathway inhibitors for the treatment of DLBCL for both species and also indicates that naturally occurring canine lymphoma could be used as a model to study therapeutic strategies for human lymphoma. The model was further validated by the identification of molecular signatures that could sub-classify canine DLBCL into activated B-cell-like (ABC) or germinal centre B-cell-like (GCB) types equivalent to human subtypes.

ORGANISM(S): Canis lupus familiaris

PROVIDER: GSE30881 | GEO | 2013/09/26

SECONDARY ACCESSION(S): PRJNA144259

REPOSITORIES: GEO

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Project description:In this study, we present the first comparison of global transcriptional changes taking place in canine lymphoma and human diffuse large B-cell lymphoma (DLBCL), with particular reference to the nuclear factor-kappaB (NF-?B) pathway. Microarray data generated from lymph nodes diagnosed with canine DLBCL and healthy lymph nodes were used for differential expression analysis, co-expression analysis and pathway analysis, and compared with analysis of publicly available microarray data from human healthy and DLBCL lymph nodes. The comparisons between species at gene level were performed by mapping the probesets in canine microarrays to orthologous genes in humans and vice versa. A considerable number of differentially expressed genes between canine lymphoma and healthy lymph node samples were also found differentially expressed between human DLBCL and healthy lymph node samples. Principal component analysis (PCA) using a literature derived 120 NF-?B target gene set mapped to 199 orthologous canine array probesets and 259 human array probesets clearly separated the healthy and cancer samples in both canine and human datasets. The analysis demonstrated that for both human and canine DLBCL there is activation of the NF-?B/p65 canonical pathway rather than the alternative pathway. This has therapeutic implications for the use of specific pathway inhibitors for the treatment of DLBCL for both species and also indicates that naturally occurring canine lymphoma could be used as a model to study therapeutic strategies for human lymphoma. The model was further validated by the identification of molecular signatures that could sub-classify canine DLBCL into activated B-cell-like (ABC) or germinal centre B-cell-like (GCB) types equivalent to human subtypes. Canine DLBCL patients were recruited via the clinical oncology service of the University of Edinburgh Royal (Dick) School of Veterinary Studies (DJA), and the University of Wisconsin-Madison School of Veterinary Medicine (DMV). Lymph node biopsy samples were taken, as part of normal diagnostic procedures, from dogs newly diagnosed with lymphoma (naïve) and samples from dogs that had relapsed following standard of care CHOP chemotherapy. Only dogs with confirmed DLBCL after pathological grading were used in this study. This included standard histopathological grading by two independent pathologists and CD3/PAX5 marker analysis. Normal lymph node samples were obtained from canines that were euthanized for non-lymphoma conditions. Microarray data were generated from 35 canine samples (25 DLBCL and 10 healthy) in total. However, data from 2 canine DLBCL samples did not meet our required quality and were removed from further analysis. Only data from 33 (23 DLBCL and 10 healthy) samples were used for analysis. The generated data were used for differential expression analysis, co-expression analysis and pathway analysis, and compared with analysis of publicly available microarray data (GSE12195) from human healthy and DLBCL lymph nodes. The comparisons between species at gene level were performed by mapping the probesets in canine microarrays to orthologous genes in humans and vice versa.

Project description:Comparative oncology is a developing research discipline that is being used to assist our understanding of human neoplastic diseases. Companion canines are a preferred animal oncology model due to spontaneous tumor development and similarity to human disease at the pathophysiological level. We use a paired RNA sequencing (RNA-Seq)/microarray analysis of a set of four normal canine lymph nodes and ten canine lymphoma fine needle aspirates to identify technical biases and variation between the technologies and convergence on biological disease pathways. Surrogate Variable Analysis (SVA) provides a formal multivariate analysis of the combined RNA-Seq/microarray data set. Applying SVA to the data allows us to decompose variation into contributions associated with transcript abundance, differences between the technology, and latent variation within each technology. A substantial and highly statistically significant component of the variation reflects transcript abundance, and RNA-Seq proved more sensitive for detection of transcripts expressed at low levels. Latent random variation among RNA-Seq samples is also distinct in character from that impacting microarray samples. In particular, we observed variation between RNA-Seq samples that reflects transcript GC content. Platform-independent variable decomposition without a priori knowledge of the sources of variation using SVA represents a generalizable method for accomplishing cross-platform data analysis. We identified genes differentially expressed between normal lymph nodes of disease free dogs and a subset of the diseased dogs diagnosed with B-cell lymphoma using each technology. There is statistically significant overlap between the RNA-Seq and microarray sets of differentially expressed genes. Analysis of overlapping genes in the context of biological systems suggests elevated expression and activity of PI3K signaling in B-cell lymphoma biopsies compared with normal biopsies, consistent with literature describing successful use of drugs targeting this pathway in lymphomas. RNA was extracted from 10 lymphoma fine needle aspirates attained from companion canines. 4 normal lymph node samples were obtained from a Beagle breeding colony at Pfizer, including two samples that were taken from the same dog but different lymph nodes. This Series represents the Affymetrix gene expression only, not RNA-Seq referenced above. RNA-Seq data have been submitted to SRA as SRA059558.

Dataset Information

Comparative Transcriptional Analysis of Canine and Human Diffuse Large B cell Lymphoma (DLBCL). Molecular Signatures of NF-κB Pathway Activation and Sub-Classification of Canine DLBCL.

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