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Gene signature of CLL cells cultured with activated T cells or CD40L-expressing cells

ABSTRACT: Chronic Lymphocytic Leukemia (CLL) cells multiply in secondary lymphoid tissue but the mechanisms leading to their proliferation are still uncertain. In addition to BCR-triggered signals, other microenvironmental factors might well be involved. In proliferation centres, leukemic B cells are in close contact with CD4+CD40L+ T cells. Therefore, we here dissected the signals provided by autologous activated T cells (Tact) to CLL cells. Although the gene expression profile induced by Tact was highly similar to that induced by sole CD40 signaling, an obvious difference was that Tact induced proliferation of CLL cells. We determined that stimulation with only CD40L+IL-21 was sufficient to induce robust proliferation in CLL cells. We then defined an IL-21-induced gene signature in CLL, containing components of JAK-STAT and apoptosis pathways, and this signature could be detected in lymph node (LN) samples from patients. Finally, we could detect IL-21 RNA and protein in LN, and IL-21 production ex vivo by LN CD4+CXCR5+ follicular helper T cells. These results indicate that, in addition to BCR signaling, activated T cells might contribute to CLL cell proliferation via CD40 and IL-21. Targeting these signaling pathways might offer new venues for treatment of CLL.

ORGANISM(S): Homo sapiens

PROVIDER: GSE50572 | GEO | 2013/10/07

SECONDARY ACCESSION(S): PRJNA217965

REPOSITORIES: GEO

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Project description:Expression of CD40 in non-hematopoietic cells has been linked to inflammation. We presented evidence that CD40, a T-cell costimulatory molecule, is expressed in human Î²-cells and the engagement of CD40 in insulinoma cells activated the NFKB and ERK1/2 pathways. CD40 activation in human islets cells induced secretion of IL-8, MCP-1 and MIP-1 Î², which is abrogated by inhibitors of NFkB and ERK1/2 inhibitors. In this study, we have studied gene expression mediated by CD40-CD40L interaction in islet cells. This approach identified 90 genes and transcripts exhibiting at least a 1.7 fold increase in their expression intensity after treatment with soluble CD40L. A significant number of genes were related to inflammation and oxidative stress. We have a strong overexpression of CXCL1 (GroÎ±), CXCL2 (Mif2) and CXCL3; chemokines belonging to CXC family structurally related to Il-8. 11 genes were selected from this group and further quantified by Real Time PCR, including CXCL1. Activation of islet cells with CD40L induced the secretion of CXCL1 in a NFKB dependent manner. Engagement of CD40 in islet cells did not induce apoptosis, neither Î²-cell death and did not enhanced TNF-Î± mediated cell death as observed in insulinoma cells. CD40 activation in insulinoma cells, results in ERK1/2 dependent phsophorylation of synapsin I, a protein associated with the exocytosis machinery in neurons and Î²-cells. However, treatment of islets with soluble CD40L did not affect glucose induced insulin secretion. It has been reported that ductal cells always present in human islet preparations express CD40 constitutively (ref). We found that CD40-CD40L interaction in ductal cells, unlike in Î²-cells, induces secretion of diabetogenic cytokines IFNÎ³ and TNF-Î±. Furthermore, incubation of islets containing ductal cells with CD40L decreased Î²-cells viability as assessed by measurement of their mitochondrial membrane potential Experiment Overall Design: We isolated islet cells from three patients. Part of islet cells from each patient has been treated with CD40L. We compared gene expression in treated cells vs untreated for each patient using dye-swap.

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Gene signature of CLL cells cultured with activated T cells or CD40L-expressing cells

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