Gene expression data from chronic lymphocytic leukemia samples
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ABSTRACT: MicroRNA-155 is frequently over-expressed in CLL and is associated with worse clinical prognosis. To understand the role of miR-155 in CLL pathogenesis, we used microarrays to identify genes that are expressed at significantly lower levels in CLLs that harbor higher levels of miR-155 expression in an attempt to determine the relevant gene targets of miR-155 in CLL. MiR-155 levels of 38 CLL samples were determined and ranked. 6 CLLs with the highest and 6 CLLs with the lowest miR-155 within the IgVH unmutated group, and 5 CLLs with the highest and 5 CLLs with the lowest miR-155 within the IgVH mutated group were selected for Affymetrix array analyses.
Project description:MicroRNA-155 is frequently over-expressed in CLL and is associated with worse clinical prognosis. To understand the role of miR-155 in CLL pathogenesis, we used microarrays to identify genes that are expressed at significantly lower levels in CLLs that harbor higher levels of miR-155 expression in an attempt to determine the relevant gene targets of miR-155 in CLL.
Project description:Several studies demonstrated IgVH mutation status and ZAP-70 expression as the most relevant prognostic markers in CLL, suggesting the separation of two patient subgroups: with good (MTZAP-70-) and poor prognosis (UMZAP-70+). We determined gene expression of B cells in 112 CLL patients divided into three classes: the first with IgVHMT and ZAP-70-, the second with IgVHUM and ZAP-70+, and the third included both IgVHUM ZAP-70- and IgVHMT ZAP-70+. We found LPL, AGPAT2, MBOAT1, CHPT1, AGPAT4, PLD1 genes encoding enzymes involved in lipid (glycerolipid/glycerophospholipid) metabolism overexpressed in UMZAP-70+. In addition, this study demonstrates the role of ARSD, a gene belonging to the sphingolipid metabolism, as a new gene significantly overexpressed in UMZAP-70+ in respect to MTZAP-70-. ARSD protein was found at significantly higher concentrations in UMZAP-70+ compared to MTZAP-70- CLL B cells and B cells from healthy individuals by Western blotting. Statistical analysis identified a strong correlation between ARSD and IgVH mutation status; ARSD protein level was associated with the requirement of therapy for CLL patients and for this purpose it is as good as IgVH mutational status. Our study highlights ARSD as a promising new prognostic factor in CLL and sphingolipid metabolism as a putative new biological mechanism in CLL. In this study we performed gene expression profiling of B cells on 112 CLL patients divided into three classes based on IgVH mutational status and ZAP-70 protein expression: class one with mutated IgVH and ZAP-70-, class two with unmutated IgVH and ZAP-70+, and class three included CLL patients with unmutated IgVH and ZAP-70-, or mutated IgVH and ZAP-70+, respectively. The decision to divide CLL patients in three categories was due to the clinical feature and the molecular heterogeneity of CLL, in order to elaborate different molecular signature capable of reveal biological mechanisms, and to identify new potential molecular predictors for prognostic assessment or genetic risk. RNA was extracted and quantified for high-density oligonucleotide microarrays Human Genome U133 Plus 2.0 GeneChip (Affymetrix, Santa Clara, CA). A first cohort of 62 subjects was analyzed using GeneChip Expression 3' Amplification One-Cycle Target Labeling Kit, while a second cohort of 50 subjects using GeneChip 3'IVT Express Kit, according to manufacturerM-bM-^@M-^Ys protocol (Affymetrix), respectively.
Project description:We studied the value of the microRNAs as a signature for CLL patients with specific chromosomal abnormalities. We identified 32 microRNAs able to discriminate the 11q deletion, 17p deletion, trisomy 12, and 13q deletion and normal karyotype cytogenetic subgroups. The expression values of 9 among the 32 microRNAs (miR-151-3p, miR-34a, miR-29c, miR-29b, miR-155, miR-148a, miR-146a, miR-146b5p and miR-640) were correlated with genes expression data from the same samples to assess their biological impact on CLL. In this study we also found that IGHV unmutated, high expression of ZAP-70 protein and low expression of the miR-223, miR-29c, miR-29b, and miR-181 family were strongly associated with disease progression in CLL cases harboring 17p deletion; whereas in those harboring trisomy 12 only high expression of the miR-181a, among the analyzed parameters, suggested more aggressive disease. Thus, the use of the microRNA-based classifications may yield clinically useful bio-markers of tumor behavior in CLL.
Project description:We studied the value of the microRNAs as a signature for CLL patients with specific chromosomal abnormalities. We identified 32 microRNAs able to discriminate the 11q deletion, 17p deletion, trisomy 12, and 13q deletion and normal karyotype cytogenetic subgroups. The expression values of 9 among the 32 microRNAs (miR-151-3p, miR-34a, miR-29c, miR-29b, miR-155, miR-148a, miR-146a, miR-146b5p and miR-640) were correlated with genes expression data from the same samples to assess their biological impact on CLL. In this study we also found that IGHV unmutated, high expression of ZAP-70 protein and low expression of the miR-223, miR-29c, miR-29b, and miR-181 family were strongly associated with disease progression in CLL cases harboring 17p deletion; whereas in those harboring trisomy 12 only high expression of the miR-181a, among the analyzed parameters, suggested more aggressive disease. Thus, the use of the microRNA-based classifications may yield clinically useful bio-markers of tumor behavior in CLL.
Project description:In this study we compared the miRNA expression profile of 217 CLL cases versus various normal B cell subpopulations in the attempt of finding the normal cell subset most similar to CLL cells and gain information on possible miRNA deregulations. Our analyses indicated that CLL cells exhibited a miRNA expression pattern close to memory and marginal zone-like B cells. Conversely, tonsil GC and CD19+ peripheral blood B cells appeared only distantly related to CLL. Memory and marginal zone B cells were used as reference to identify differentially expressed miRNAs in CLL, which included miR-193b, miR-33b*, miR-365, miR-181b and miR-196a/b among the down-regulated and miR-23a/b, miR-26a, miR-130a, miR-532 (5p and 3p) among the up-regulated miRNAs. We also investigated differences of miRNA expression related to the IGHV somatic mutation status and to deletions at 13q, 11q and 17p or trisomy 12. Little differences were detected between unmutated (UM) versus mutated (M) CLLs, although miR-29c, miR-29c* and miR-146b were strongly down-modulated in the UM-CLL subgroup. Each of the cytogenetic classes of CLL was characterized by uniquely abnormally expressed miRNAs. Deletion at 13q displayed a reduced expression of miR-16, more evident if the deletion was biallelic. Deletion of 17p was characterized by the strong reduction of miR-34a expression and up-regulation of miR-96. Deletion at 11q was characterized by the up-regulation of miR-338-3p and miR-769-5p. Trisomy 12 was characterized by a strong down-regulation of miR-483-5p.
Project description:Chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease characterized by chromosomal aberrations of prognostic significance. Recent studies showed that gain of chromosome 2p is a recurrent lesion in CLL. We investigated the 2p gain and its relationship with prognostic biomarkers in a prospective series of 287 early-stage CLLs (Binet A). The 2p gain was detected by FISH in 17 patients (6%) and further characterized by single nucleotide polymorphism-array. Overall, unfavorable cytogenetic deletions, i.e. del(11)(q23) and del(17)(p13) (P=0.002) as well as unmutated (UM) status of IGHV (P<1×10-4) and CD38 (P<1×10-4) and ZAP-70 positive expression (P=0.003) were significantly more prevalent in 2p gain cases. Furthermore, 2p gained patients showed a significantly higher occurrence of stereotyped HCDR3 sequences compared to 2p normal CLLs (P=0.009). Among the stereotyped subsets, the incidence of subset #1 in 2p positive patients was significantly higher than that found in the remaining CLLs (P=0.031). Finally, gene expression profiling analysis identified a number of genes significantly upregulated in 2p gain CLLs. Among those located at 2p, NCOA1 and ROCK2 are known for their involvement in tumor progression in several human cancers, whereas among those located in different chromosomes, CAV1 at 7q31.1 has been recently identified to play a critical role in CLL progression. Our study indicates that 2p gain is a recurrent lesion in early CLL, correlated with the major biological and cytogenetic risk markers of the disease. Moreover, we provide insights to define novel candidate genes that may play additional pathogenetic roles in CLL.
Project description:Chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease characterized by chromosomal aberrations of prognostic significance. Recent studies showed that gain of chromosome 2p is a recurrent lesion in CLL. We investigated the 2p gain and its relationship with prognostic biomarkers in a prospective series of 287 early-stage CLLs (Binet A). The 2p gain was detected by FISH in 17 patients (6%) and further characterized by single nucleotide polymorphism-array. Overall, unfavorable cytogenetic deletions, i.e. del(11)(q23) and del(17)(p13) (P=0.002) as well as unmutated (UM) status of IGHV (P<1×10-4) and CD38 (P<1×10-4) and ZAP-70 positive expression (P=0.003) were significantly more prevalent in 2p gain cases. Furthermore, 2p gained patients showed a significantly higher occurrence of stereotyped HCDR3 sequences compared to 2p normal CLLs (P=0.009). Among the stereotyped subsets, the incidence of subset #1 in 2p positive patients was significantly higher than that found in the remaining CLLs (P=0.031). Finally, gene expression profiling analysis identified a number of genes significantly upregulated in 2p gain CLLs. Among those located at 2p, NCOA1 and ROCK2 are known for their involvement in tumor progression in several human cancers, whereas among those located in different chromosomes, CAV1 at 7q31.1 has been recently identified to play a critical role in CLL progression. Our study indicates that 2p gain is a recurrent lesion in early CLL, correlated with the major biological and cytogenetic risk markers of the disease. Moreover, we provide insights to define novel candidate genes that may play additional pathogenetic roles in CLL.
Project description:Chromatin interactions play important roles in regulating gene expression. However, the availability of genome-wide chromatin interaction data is limited. Various computational methods have been developed to predict chromatin interactions. Most of these methods rely on large collections of ChIP-Seq/RNA-Seq/DNase-Seq datasets and predict only enhancer-promoter interactions. Some of the ‘state-of-the-art’ methods have poor experimental designs, leading to over-exaggerated performances and misleading conclusions. Here we developed a computational method, Chromatin Interaction Neural Network (CHINN), to predict chromatin interactions between open chromatin regions by using only DNA sequences of the interacting open chromatin regions. CHINN is able to predict CTCF-, RNA polymerase II- and HiC-associated chromatin interactions between open chromatin regions. CHINN also shows good across-sample performances and captures various sequence features that are predictive of chromatin interactions. We applied CHINN to 90 chronic lymphocytic leukemia (CLL) samples and detected systematic differences in the chromatin interactome between IGVH-mutated and IGVH-unmutated CLL samples.
Project description:The cellular origin of chronic lymphocytic leukemia (CLL) is debated. Transcriptome analysis of CLL and normal peripheral blood and splenic B cell subsets displayed highest similarity of CLL to mature CD5+ B cells. We identified a distinct CD5+CD27+ post-germinal center B cell subset, and revealed that immunoglobulin V gene mutated CLL are more similar to mutated CD5+ B cells, whereas unmutated CLL are more related to unmutated CD5+ B cells. Stereotyped immunoglobulin V gene rearrangements were significantly enriched among CD5+ B cells, providing further genetic evidence for a derivation of CLL from CD5+ B cells. Moreover, we identified deregulated expression patterns providing novel insights into the pathophysiology of CLL, including downregulation of EBF1 and KLF family members. Transcriptome profiling of CLL and healthy human blood and splenic mature B cell subsets. Identification of deregulated transcription patterns with implications on CLL pathobiology.
Project description:The cellular origin of chronic lymphocytic leukemia (CLL) is debated. Transcriptome analysis of CLL and normal peripheral blood and splenic B cell subsets displayed highest similarity of CLL to mature CD5+ B cells. We identified a distinct CD5+CD27+ post-germinal center B cell subset, and revealed that immunoglobulin V gene mutated CLL are more similar to mutated CD5+ B cells, whereas unmutated CLL are more related to unmutated CD5+ B cells. Stereotyped immunoglobulin V gene rearrangements were significantly enriched among CD5+ B cells, providing further genetic evidence for a derivation of CLL from CD5+ B cells. Moreover, we identified deregulated expression patterns providing novel insights into the pathophysiology of CLL, including downregulation of EBF1 and KLF family members. Transcriptome profiling of CLL and healthy human blood and splenic mature B cell subsets. Identification of deregulated transcription patterns with implications on CLL pathobiology. Human mature B cell subsets and CLL with mutated (mCLL) and unmutated V gene status (uCLL) were purified from peripheral blood and spleen. Samples of 5 to 7 donors each were collected and processed in three batches in a two rounded in vitro transcription protocol. Retrieved data were batch corrected and subjected to analysis. Human mature CD5+ B cell subsets and CLL with mutated (mCLL) and unmutated V gene status (uCLL) were purified from peripheral blood.