Project description:The standard treatment for patients with diffuse large B-cell lymphoma (DLBCL) is the immunochemotherapy-based R-CHOP regimen (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone). Resistance to treatment, intrinsic or acquired, is observed in approximately 40% of patients with DLBCL, who thus require novel interventions to survive. To identify biomarkers for cytotoxic response assessment, microRNAs (miRNAs) associated with doxorubicin sensitivity were determined by combining global miRNA expression profiling with systematic dose-response screens in 15 human DLBCL cell lines. One candidate, miR-34a, was tested in functional in vitro studies and in vivo in a retrospective clinical cohort. High expression of miR-34a was observed in cell lines sensitive to doxorubicin, and upregulation of miR-34a is documented here to increase doxorubicin sensitivity in in vitro lentiviral transduction assays. High expression of miR-34a had a prognostic impact using overall survival as outcome. With risk stratification of DLBCL samples based on resistance gene signatures (REGS), doxorubicin-responsive samples had statistically significant upregulated miR-34a expression. Classification of the DLBCL samples into subset-specific B cell-associated gene signatures (BAGS) revealed differentiation-specific expression of miR-34a. Our data further support FOXP1 as a target of miR-34a, suggesting that downregulation of FOXP1 may sensitize DLBCL cells to doxorubicin. We conclude that miRNAs, in particular miR-34a, may have clinical utility in DLBCL patients as both predictive and prognostic biomarkers.
Project description:Current staging classifications do not accurately predict the benefit of high-dose chemotherapy (HDC) with autologous stem-cell transplantation (ASCT) for patients with diffuse large B-cell lymphoma (DLBCL) at high risk (age-adjusted International Index [aaIPI] score 2 or 3), who have achieved first complete remission after R-CHOP (rituximab, cyclophosphamide, vincristine, doxorubicin, and prednisone) treatment. We aim to construct a genetic prognostic model for improving individualized risk stratification and response prediction for HDC/ASCT therapy. We identified differentially expressed mRNAs associated with relapse of DLBCL.
Project description:MicroRNAs (miRNAs or miRs) are small, noncoding RNAs that are implicated in the regulation of nearly all biological processes. Global miRNA biogenesis is altered in many cancers and RNA-binding proteins (RBPs) have been shown to play a role in this process, presenting a promising avenue for targeting miRNA dysregulation in disease. miR-34a exhibits tumor-suppressive functions by targeting cell cycle regulators CDK4/6 and anti-apoptotic factor Bcl-2, among other regulatory pathways such as Wnt, TGF-, and Notch signaling. Many cancers show downregulation or loss of miR-34a, and synthetic miR-34a supplementation has been shown to inhibit tumor growth in vivo; however, the post-transcriptional mechanisms by which miR-34a is lost in cancer are not entirely understood. Here, we have used a proteomics-mediated approach to identify Squamous cell carcinoma antigen recognized by T-cells 3 (SART3) as a putative pre-miR-34a-binding protein. SART3 is a spliceosome recycling factor and nuclear RBP with no previously reported role in miRNA regulation. We demonstrate that SART3 binds pre-miR-34a with specificity over pre-let-7d and begin to elucidate a new functional role for this protein in non-small lung cancer cells. Overexpression of SART3 led to increased miR-34a levels, downregulation of the miR-34a target genes CDK4 and CDK6, and cell cycle arrest in the G1 phase. In vitro binding studies showed that the RNA-recognition motifs within the SART3 sequence are responsible for selective pre-miR-34a binding. Collectively, our results present evidence for an influential role of SART3 in miR-34a biogenesis and cell cycle progression.
Project description:Despite the long-standing role of standard chemotherapy in human diffuse large B cell lymphoma (DLBCL), the basis for individual tumor responses and how they associate with different transcriptional programs are incompletely understood. Hence we aimed to classify DLBCL cell lines by their ability to undergo therapy-induced senescence (TIS) in response to adriamycin (aka doxorubicin) and acquire gene expression profiles before and after chemotherapy by RNA-seq.
Project description:A "Cartes d'Identite des Tumeurs" (CIT) project from the french Ligue Nationale Contre le Cancer (http://cit.ligue-cancer.net). 53 samples hybridized on Affymetrix HG-U133A GeneChips arrays, for 53 patients with diffuse large B-cell lymphoma (DLBCL); patients are treated with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) or Ritxumab (R)-CHOP in the Groupe dB^REtude des Lymphomes de lB^RAdulte (GELA) clinical centers.
Project description:This SuperSeries is composed of the following subset Series: GSE21846: Transcriptional profiling of 29 cases of diffuse large B cell lymphoma GSE21847: miRNA profiling of 29 cases of diffuse large B cell lymphoma GSE21848: miRNA profiling of 36 cases of diffuse large B cell lymphoma Refer to individual Series
Project description:This SuperSeries is composed of the following subset Series: GSE30357: Chip-chip from human diffuse large B cell lymphoma cell lines with IRF8 GSE30358: Mouse B cell lymphoma cell lines:IRF8 knockdown cells vs. Control GSE30519: Chip-chip from mouse diffuse large B cell lymphoma cell lines with IRF8 GSE30520: Chip-chip from mouse diffuse large B cell lymphoma cell lines with PU.1 Refer to individual Series
Project description:Plasmablastic lymphoma is a high grade B cell lymphoma with plasmablastic morphology and a terminally differentiated B cell immunophenotype, usually arising in the setting of immunodeficiency and often demonstrating Epstein Barr Virus positivity. The molecular and genetic mechanisms underlying the pathogenesis of PBL are largely unknown. To better understand its pathogenesis, herein we have analyzed global gene expression of PBL and compared that to gene expression profiles of diffuse large B cell lymphoma. While overlaps in transcriptomes between these malignancies were identified, we have shown that the gene expression profile of plasmablastic lymphoma is distinct, demonstrating striking downregulation of B cell receptor signaling genes, BCL6, BCL11A SPI-B, targets of NFKB1, and upregulation of mitochondrial genes, PRMT5, MYC and MYC targets and IL21, implicating these alterations in the pathogenesis of this lymphoma. In addition we show the usefulness of SWAP-70 immunohistochemistry in the differentiation of immunoblastic diffuse large B cell lymphoma and plasmablastic lymphoma. Our findings provide justification for considering plasmablastic lymphoma as a specific lymphoma entity and provide insight into the unique transcriptional aberrations occurring in this high-grade lymphoma. Expression profiles of 15 plasmablastic lymphomas and 10 diffuse large B-cell lymphomas were obtained using Afymmetrix U133A2 microarrays.