TY - JOUR
T1 - Tumor necrosis factor-α and CD40L modulate cell surface morphology and induce aggregation in Ramos Burkitt's lymphoma cells
AU - Laskov, Reuven
AU - Berger, Nir
AU - Scharff, Matthew D.
AU - Horwitz, Marshall S.
N1 - Funding Information:
We thank Manxia Fan for help in maintaining some of the cell lines, Drs C. Woo and S. Fessler for help in the flow cytometric analysis, Leslie Gunther and Caroline Marks for the SEM and TEM analyses, Dr J. Berman for the anti-CD54 and its isotype control reagents, Drs H. Ben-Bassat, Z. Shlomai and H. Ye for providing some of the B-lymphoma and LCL lines, Dr N. Grover for help in the statistical analysis, and Yossi Markson for art work. The research was supported by National Institutes of Health (NIH) grant 1PO1 DK-52956 to M. S. Horwitz, NIH CA72649 and AI 43937 grants to M. D. Scharff, and a grant from the chief scientist of the Israel Ministry of Health (No. 4515) to R. Laskov.
PY - 2006/3
Y1 - 2006/3
N2 - Interaction of CD40L and its cognate receptor is an essential component of B-lymphocyte signaling, affecting various aspects of B-cell differentiation pathways and immunoglobulin gene expression. However, much less is known about the biological consequences of B-cell signaling through tumor necrosis factor (TNF)-α and its cognate receptors TNF-R1 and 2. We used Ramos Burkitt's lymphoma cell line as a model system to study the direct effects of these cytokines on B cells. Treatment of Ramos cells with either TNF-α or CD40L, but not with interleukin (IL)- 4, interferon (IFN)-γ and transforming growth factor (TGF)-β, resulted in enhanced cell aggregation and enhancement of adherence to glass cover-slips. Scanning electron microscopy showed that Ramos cells have a polarized cell surface morphology and exhibit at least 3 cell surface morphological domains: microvilli, filopodia and ruffled membranes. The cells adhered to the glass matrix through multiple filopodia/podopodia-like cell processes and demonstrated distinct ruffled-like membrane projections on their opposite pole. Induction by TNF-α or CD40L, but not with IL-4, IFN-γ and TGF-β, resulted in increased number and complexity of both types of membrane projections. TNF-α and CD40L upregulated the expression of the adhesion molecule intercellular adhesion molecule-1 and the Fas receptor on Ramos cells, without affecting the expression levels of membrane immunoglobulin M or its secretion rate. Reverse transcriptase-polymerase chain reaction, and flow cytometry demonstrated that Ramos cells expressed TNF-R1 but very little if any TNF-R2, indicating that TNF-α exerted its effects on Ramos cells through the former receptor.
AB - Interaction of CD40L and its cognate receptor is an essential component of B-lymphocyte signaling, affecting various aspects of B-cell differentiation pathways and immunoglobulin gene expression. However, much less is known about the biological consequences of B-cell signaling through tumor necrosis factor (TNF)-α and its cognate receptors TNF-R1 and 2. We used Ramos Burkitt's lymphoma cell line as a model system to study the direct effects of these cytokines on B cells. Treatment of Ramos cells with either TNF-α or CD40L, but not with interleukin (IL)- 4, interferon (IFN)-γ and transforming growth factor (TGF)-β, resulted in enhanced cell aggregation and enhancement of adherence to glass cover-slips. Scanning electron microscopy showed that Ramos cells have a polarized cell surface morphology and exhibit at least 3 cell surface morphological domains: microvilli, filopodia and ruffled membranes. The cells adhered to the glass matrix through multiple filopodia/podopodia-like cell processes and demonstrated distinct ruffled-like membrane projections on their opposite pole. Induction by TNF-α or CD40L, but not with IL-4, IFN-γ and TGF-β, resulted in increased number and complexity of both types of membrane projections. TNF-α and CD40L upregulated the expression of the adhesion molecule intercellular adhesion molecule-1 and the Fas receptor on Ramos cells, without affecting the expression levels of membrane immunoglobulin M or its secretion rate. Reverse transcriptase-polymerase chain reaction, and flow cytometry demonstrated that Ramos cells expressed TNF-R1 but very little if any TNF-R2, indicating that TNF-α exerted its effects on Ramos cells through the former receptor.
KW - B-lymphoma
KW - Filopodia
KW - ICAM-1
KW - Ruffled membrane
KW - Scanning electron microscopy
KW - TNF receptors
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U2 - 10.1080/10428190500221454
DO - 10.1080/10428190500221454
M3 - Article
C2 - 16523591
AN - SCOPUS:30844435948
SN - 1042-8194
VL - 47
SP - 507
EP - 519
JO - Leukemia and Lymphoma
JF - Leukemia and Lymphoma
IS - 3
ER -