Project description:Stabilizing mutations of NOTCH1 have been identified in about 10% of chronic lymphocytic leukemia (CLL) cases at diagnosis, with a higher frequency in unmutated IGHV (IGHV-UM) CLL, chemorefractory CLL and CLL in advanced disease phases. Clinically, the presence of NOTCH1 mutations is an independent predictor of overall survival in CLL and associates with resistance to anti-Cd20 immunotherapy. The Gene Expression Profile was generated to identify the peculiar molecular signatures of NOTCH1 mutated CLL in the context of IGHV-UM CLL.
Project description:The B-cell receptor (BCR) plays an important role in pathogenesis and progression of chronic lymphocytic leukemia (CLL). We investigated the BCR triggering-dependent microRNA modulation by stimulating CLL cells with immobilized anti-IgM. miRome of immobilized anti-IgM stimulated CLL cells (n=16) identified a substantial upregulation of miR-132 in both unmutated (UM) and mutated (M) IGHV subgroups. A parallel gene expression profile and an in-silico analysis to identify miR-132 target genes¸ allowed us to focus on SIRT1, that encodes for a histone deacetylase targeting several proteins including TP53. We defined a reduction of SIRT1 protein levels upon immobilized anti-IgM stimulation (P=0.001), and a concomitant increase in TP53 acetylation (P=0.0072). The TP53 target gene CDKN1A was consistently up-regulated in immobilized anti-IgM stimulated CLL cells. Of note, the miR-132 constitutive expression levels in CLL cases (n=134) were of similar magnitude of those obtained in in vitro immobilized anti-IgM stimulated CLL cells. Additionally, high miR-132 expression levels retained a favorable prognostic impact in M (P=0.005), but not in UM CLL patients (P=0.968). The described miR-132/SIRT1/TP53 axis, sequentially characterized by BCR triggering, miR-132 up-regulation, SIRT1 down-regulation and TP53 acetylation, should be considered in the light of emerging drugs targeting the BCR pathway in CLL.
Project description:The B-cell receptor (BCR) plays an important role in pathogenesis and progression of chronic lymphocytic leukemia (CLL). We investigated the BCR triggering-dependent mRNA modulation by stimulating CLL cells with immobilized anti-IgM. miRome of immobilized anti-IgM stimulated CLL cells (n=16) identified a substantial upregulation of miR-132 in both unmutated (UM) and mutated (M) IGHV subgroups. A parallel gene expression profile and an in-silico analysis to identify miR-132 target genes¸ allowed us to focus on SIRT1, that encodes for a histone deacetylase targeting several proteins including TP53. We defined a reduction of SIRT1 protein levels upon immobilized anti-IgM stimulation (P=0.001), and a concomitant increase in TP53 acetylation (P=0.0072). The TP53 target gene CDKN1A was consistently up-regulated in immobilized anti-IgM stimulated CLL cells. Of note, the miR-132 constitutive expression levels in CLL cases (n=134) were of similar magnitude of those obtained in in vitro immobilized anti-IgM stimulated CLL cells. Additionally, high miR-132 expression levels retained a favorable prognostic impact in M (P=0.005), but not in UM CLL patients (P=0.968). The described miR-132/SIRT1/TP53 axis, sequentially characterized by BCR triggering, miR-132 up-regulation, SIRT1 down-regulation and TP53 acetylation, should be considered in the light of emerging drugs targeting the BCR pathway in CLL.
Project description:Single Gland Whole-exome sequencing: building on our prior description of multi-region WES of colorectal tumors and targeted single gland sequencing (E-MTAB-2247), we performed WES of multiple single glands from different sides (right: A and left: B) of two tumors in this study (tumor O and U) on the illumina platform using the Agilent SureSelect 2.0 or illumina Nextera Rapid Capture Exome kit (SureSelect or NRCE, as indicated in the naming of fastq files). Colorectal Cancer Xenograft Whole-exome sequencing: The HCT116 and LoVo Mismatch-Repair-deficient colorectal adenocarcinoma cell lines were obtained from the ATCC and cultured under standard conditions. For both cell lines, a single âfoundingâ cell was cloned and expanded in vitro to ~6M cells. Two aliquots of ~1M cells were subcutaneously injected into opposite flanks (right and left) of a nude mouse and tumors allowed to reach a size of ~1B cells (1cm3) before the animal was sacrificed. Tumor tissue was collected separately from the right and left lesions and DNA was extracted for WES using the illumina TruSeq Exome kit or Nextera Rapid Capture Exome expanded Kits (Truseq or NRCEe), as was DNA from the first passage population (a polyclonal tissue culture for HCT116 and a polyclonal xenograft sample for LoVo), which were employed as a control to study mutation accumulation in culture and post xenotransplantation.