Project description:In the present study, the methylation profiling (MeDIP) was carried out in 14 treatment-naive, early stage (Rai stage 0-2) CLL patients and pooled 19+ normal controls. To find an association of methylation with IGHV mutation status, CLL patients were further segregated into IGHV unmutated (n=9) and IGHV mutated (n=5) subgroups. The methylation signature obtained for CLL versus nornal controls and; unmutated versus mutated CLL was integrated with gene expression profile of these patients and the results were correlated with clinical outcome.
Project description:In the present study, the gene expression profiling was carried out in 21 early stage CLL patients. A gene expression signature was generated for CLL patients as compared to normal controls; CLL patients were further seggregated into IGHV unmutated (n=10) and IGHV mutated (n=11) subgroups. The expression pattern was confirmed using real time quantitative PCR and the results were correlated with clinical outcome.
Project description:Clonal evolution occurs during the course of chronic lymphocytic leukemia (CLL) and activation-induced deaminase (AID) could influence this process. However, this possibility has been questioned in CLL because the number of circulating AID mRNA(+) cells is exceedingly low; synthesis of AID protein by blood CLL cells has not been demonstrated; the full range of AID functions is lacking in unmutated CLL (U-CLL), and no prospective analysis linking AID expression and disease severity has been reported. The results of the present study show that circulating CLL cells and those within secondary lymphoid tissues can make AID mRNA and protein. This production is related to cell division because more AID mRNA was detected in recently divided cells and AID protein was limited to the dividing fraction and was up-regulated on induction of cell division. AID protein was functional because AID(+) dividing cells exhibited more double-stranded DNA breaks, IGH class switching, and new IGHV-D-J mutations. Each of these actions was documented in U-CLL and mutated CLL (M-CLL). Furthermore, AID protein was associated with worse patient outcome and adverse cytogenetics. We conclude that the production of fully functional AID protein by U-CLL and M-CLL cells could be involved in clonal evolution of the disease.
Project description:The immunoglobulin heavy-chain variable region (IGHV) mutational status is a strong determinant of remission duration in chronic lymphocytic leukemia (CLL). The aim of this work was to compare the multidrug resistance (MDR) signature of IGHV mutated and unmutated CLL cells, identifying biochemical and molecular targets potentially amenable to therapeutic intervention.We found that the mevalonate pathway-dependent Ras/ERK1-2 and RhoA/RhoA kinase signaling cascades, and the downstream HIF-1?/P-glycoprotein axis were more active in IGHV unmutated than in mutated cells, leading to a constitutive protection from doxorubicin-induced cytotoxicity. The constitutive MDR phenotype of IGHV unmutated cells was partially dependent on B cell receptor signaling, as shown by the inhibitory effect exerted by ibrutinib. Stromal cells further protected IGHV unmutated cells from doxorubicin by upregulating Ras/ERK1-2, RhoA/RhoA kinase, Akt, HIF-1? and P-glycoprotein activities. Mevalonate pathway inhibition with simvastatin abrogated these signaling pathways and reversed the resistance of IGHV unmutated cells to doxorubicin, also counteracting the protective effect exerted by stromal cells. Similar results were obtained via the targeted inhibition of the downstream molecules ERK1-2, RhoA kinase and HIF-1?.Therefore, targeting the mevalonate pathway and its downstream signaling cascades is a promising strategy to circumvent the MDR signature of IGHV unmutated CLL cells.
Project description:High Expression of Lymphocyte-Activation Gene 3 in Chronic Lymphocytic Leukemia Cells is Associated with Unmutated IGHV and Reduced Treatment-Free Survival
Project description:The aim is to identify the differential miRNA expression profile of B-CLL stimulated with different type of stimulation CPG One color design, 36 samples, Two-condition experiment, CPG-stimulated B-CLL unmutated and mutated vs. Unstimulated B-CLL unmutated and mutated. Biological replicates: 18 unstimulated replicates, 18 CPG-stimulated replicates.
Project description:IntroductionMolecular alterations leading progression of asymptomatic CLL-like high-count monoclonal B lymphocytosis (hiMBL) to chronic lymphocytic leukemia (CLL) remain poorly understood. Recently, genome-wide association studies have found 6p21.3, where the human leukocyte antigen (HLA) system is coded, to be a susceptibility risk region for CLL. Previous studies have produced discrepant results regarding the association between HLA and CLL development and outcome, but no studies have been performed on hiMBL.AimsWe evaluated the role of HLA class I (-A, -B and -C) and class II (-DRB1 and -DQB1) in hiMBL/CLL susceptibility, hiMBL progression to CLL, and treatment requirement in a large series of 263 patients diagnosed in our center with hiMBL (n = 156) or Binet A CLL (n = 107).ResultsNo consistent association between HLA specificities and hiMBL or CLL susceptibility was found. With a median follow-up of 7.7 years, 48/156 hiMBLs (33%) evolved to asymptomatic CLLs, while 16 hiMBLs (10%) and 44 CLLs (41%) required treatment. No HLA specificities were found to be significantly associated with hiMBL progression or treatment in the whole cohort. However, within antigen-experienced immunoglobulin heavy-chain (IGHV)-mutated hiMBLs, which represents the highest proportion of hiMBL cases (81%), the presence of HLA-DQB1*03 showed a trend to a higher risk of progression to CLL (60% vs. 26%, P = 0.062). Moreover, HLA-DQB1*02 specificity was associated with a lesser requirement for 15-year treatment (10% vs. 36%, P = 0.012).ConclusionIn conclusion, our results suggest a role for HLA in IGHV-mutated hiMBL prognosis, and are consistent with the growing evidence of the influence of 6p21 on predisposition to CLL. Larger non-biased series are required to enable definitive conclusions to be drawn.