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. investigated the BCR triggering-dependent gene expression modulation by stimulating CLL cells with immobilized anti-IgM.
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. Investigated the BCR triggering-dependent gene expression modulation by stimulating CLL cells with immobilized anti-IgM.
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: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:In the marrow and lymphatic tissues, chronic lymphocytic leukemia (CLL) cells interact with accessory cells that constitute the leukemia microenvironment. In lymphatic tissues, CLL cells are interspersed with CD68+ nurselike cells (NLC) and T cells. However, the mechanism regulating co-localization of CLL cells and these accessory cells are largely unknown. To dissect the molecular cross-talk between CLL and NLC, we profiled the gene expression of CD19-purified CLL cells before and after co-culture with NLC. NLC co-culture induced high-level expression of B cell maturation antigen (BCMA) and two chemoattractants (CCL3, CCL4) by CLL cells. Supernatants from CLL-NLC co-cultures revealed high CCL3/CCL4 protein levels. B cell receptor triggering also induced a robust induction of CCL3 and CCL4 expression by CLL cells, which was almost completely abrogated by a specific Syc inhibitor, R406. High CCL3 and CCL4 plasma levels in CLL patients suggest that activation of this pathway plays a role in vivo. These studies reveal a novel mechanism of cross-talk between CLL cells and their microenvironment, namely the secretion of two T cell chemokines by CLL-NLC interaction and in response to BCR stimulation. Through these chemokines, CLL cells can recruit accessory cells, and thereby actively create a microenvironment that favors their growth and survival.
Project description:Purpose: The chromosomal deletion 11q affects biology and clinical outcome in CLL but del11q-deregulated genes remain incompletely characterized. Results: We have identified differential expression of the insulin receptor (INSR) in CLL, including high-level INSR expression in the majority of CLL with del11q. High INSR mRNA expression in 11q CLL (~10-fold higher mean levels than other genomic categories) was confirmed by Q-PCR in 247 CLL cases. INSR protein measurements in 257 CLL cases through FACS, compared with measurements in normal CD19+ B-cells and monocytes, confirmed that a subset of CLL aberrantly expresses high INSR levels.