Resistence to CD95-mediated apoptosis of CD40-activated chronic lymphocytic leukemia B cells is not related to lack of DISC molecules expression
| Autor: | Marco Gobbi, Ombretta Rosso, M. Montera, Robin Foà, Marino Clavio, Enrico Balleari, Daniela de Totero |
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| Jazyk: | angličtina |
| Rok vydání: | 2004 |
| Předmět: |
Male
apoptosis b-cll cd40-triggering cd95 disc complex Chronic lymphocytic leukemia Fas-Associated Death Domain Protein chemical and pharmacologic phenomena Apoptosis Biology Caspase 8 Lymphocyte Activation Transfection hemic and lymphatic diseases medicine Humans FADD RNA Messenger fas Receptor CD40 Antigens Adaptor Proteins Signal Transducing Aged Aged 80 and over CD40 Gene Expression Regulation Leukemic Proteins hemic and immune systems Hematology Middle Aged Fas receptor medicine.disease TRADD Leukemia Lymphocytic Chronic B-Cell TNF Receptor-Associated Factor 1 Coculture Techniques Cell biology Up-Regulation Caspases Cancer research biology.protein Tumor necrosis factor alpha Female biological phenomena cell phenomena and immunity Carrier Proteins Signal Transduction |
| Popis: | In B-cell chronic lymphocytic leukemia (CLL), accumulation of neoplastic B cells may be the result of dysregulated apoptosis. One of the major molecules triggering apoptosis, CD95 (FAS), is not expressed on CLL B cells at resting conditions. However, CD40 triggering of CLL B cells upregulates receptors belonging to the tumor necrosis factor (TNF) superfamily, like CD95. In the present study, we analyzed in B cells from 20 CLL patients the effect of CD40/CD40L interaction on: (i) CD95 modulation; (ii) CD95-mediated apoptosis and (iii) mRNA and protein expression of the death-inducing signaling complex (DISC) molecules.CD40 activation of CLL B cells was carried out by coculture with CD40L-transfected cells and cytofluorimetric analyses were performed to study CD95 modulation and apoptosis induction by an anti-CD95 moAb. Despite strong CD95 upregulation on the membrane of all the cases studied, only a minority of cases analyzed (3/20) proved weakly responsive to CD95-mediated apoptosis. Multiplex RT-PCR was used to analyze FLICE, FAS, FADD and TRADD mRNAs before and after CD40 triggering. In agreement with the cytofluorimetric data, FAS mRNA appeared significantly increased after CD40 triggering; the other molecules involved in DISC formation and in CD95-mediated apoptosis were also expressed without relevant differences between resting and activated conditions. Western blot analyses further confirmed FLICE and FADD protein expression by resting and activated CLL cells. Our findings demonstrate that, following CD40 triggering, CLL B cells are resistant to CD95-mediated apoptosis despite a strong CD95 upregulation on the membrane and a normal mRNA or protein expression of the DISC components. |
| Databáze: | OpenAIRE |
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