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CLL: CD38+CD49d+ vs. CD38-CD49d-

ABSTRACT: CD38 and CD49d are associated negative prognosticators in chronic lymphocytic leukemia (CLL). Despite evidence that both molecules are involved in interactions occurring between CLL and normal cells in the context of CLL-involved tissues, a functional link is still missing. Using gene expression profiles comparing CD38+CD49d+ vs. CD38-CD49d- CLL cells, we demonstrated overexpression of the CCL3 and CCL4 chemokines in cells from the former group. These chemokines were also upregulated by CD38 signals in CLL; moreover, CCL3 was expressed by CLL cells from bone marrow biopsies (BMB) of CD38+CD49d+ but not CD38-CD49d- cases. High levels of CCR1 and, to a lesser extent, CCR5, the receptors for CCL3 and CCL4, were found in CLL-derived monocyte-macrophages. Consistently, CCL3 increased monocyte migration, and CD68+ macrophage infiltration was particularly high in BMB from CD38+CD49d+ CLL. Conditioned media from CCL3-stimulated macrophages induced endothelial cells to express VCAM-1, the CD49d ligand, likely through TNFα over-production. These effects were apparent in BMB from CD38+CD49d+CLL, where lymphoid infiltrates were characterized by a prominent meshwork of VCAM-1+ stromal/endothelial cells. Lastly, CD49d engagement by VCAM-1-transfectants increased viability of CD38+CD49d+ CLL cells. Altogether, CD38 and CD49d can be thought of as a part of a consecutive chain of events ultimately leading to improved survival of CLL cells.

ORGANISM(S): Homo sapiens

PROVIDER: GSE14560 | GEO | 2009/03/03

SECONDARY ACCESSION(S): PRJNA111739

REPOSITORIES: GEO

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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. Experiment Overall Design: The microarray part of this study included samples of CLL cells from 9 different patients, analyzed directly after purification and after 14 days of co-culture with Nurse like cells . Experiment Overall Design: In detail, RNA was isolated from CD19-purified CLL cells from 9 different patientsâ peripheral blood mononuclear cells (PBMC) after Ficoll separation and subsequent purification with CD19 MicroBeads and the MACSÂ® technology according to the manufacturerâs instructions (Miltenyi Biotec, Bergisch Gladbach, Germany). For comparison, the same CLL cell samples were co-cultured for 14 days with NLC (""14d NLC"").""). For co-culture with NLC, PBMC from patients with CLL were suspended in complete RPMI medium (RPMI1640 with 10% FCS, penicillin-streptomycin-glutamine, Gibco-BRL, Grand Island, NY) to a concentration of 1 x 107/ml (total 20 ml) and incubated for 14 days in 75 cm2 tissue culture flasks (Techno Plastic Products AG) as described previously3. Nonadherent lymphoid cells then were removed and the NLC layer was washed two times with phosphate-buffered saline (PBS). The complete removal of lymphocytes was verified by phase-contrast microscopy. The nonadherent cells together with the wash-fractions were then used for RNA preparation. In order to purify the CLL B cells prior to RNA isolation, CLL PBMC were passed through a 30 Âµm nylon mesh to obtain a single-cell suspension. Then CLL B cells were purified with CD19 MicroBeads. Subsequently RNA was extracted.

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CLL: CD38+CD49d+ vs. CD38-CD49d-

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