CD40 ligand rescues inhibitor of differentiation 3-mediated G1 arrest induced by anti-IgM in WEHI-231 B lymphoma cells.
The engagement of membrane-bound Igs (mIgs) results in growth arrest, accompanied by apoptosis, in the WEHI-231 murine B lymphoma cells, a cell line model representative of primary immature B cells. Inhibitor of differentiation (Id) proteins, members of the helix-loop-helix protein family, functions in proliferation, differentiation, and apoptosis in a variety of cell types. In this study, we analyzed the involvement of Id protein in mIg-induced growth arrest and apoptosis in WEHI-231 cells. Following stimulation with anti-IgM, expression of Id3 was up-regulated at both the mRNA and protein levels; this up-regulation could be reversed by CD40L treatment. Retrovirus-mediated transduction of the Id3 gene into WEHI-231 cells resulted in an accumulation of the cells in G(1) phase, but did not induce apoptosis. E box-binding activity decreased in response to anti-IgM administration, but increased after stimulation with either CD40L alone or anti-IgM plus CD40L, suggesting that E box-binding activity correlates with cell cycle progression. WEHI-231 cells overexpressing Id3 accumulated in G(1) phase, which was accompanied by reduced levels of cyclin D2, cyclin E, and cyclin A, and a reciprocal up-regulation of p27(Kip1). Both the helix-loop-helix and the C-terminal regions of Id3 were required for growth-suppressive activity. These data suggest that Id3 mimics mIg-mediated G(1) arrest in WEHI-231 cells.
Hata
Kikumi
K
Department of Immunology, Tokyo Medical University, Japan.
Yoshimoto
Takayuki
T
Mizuguchi
Junichiro
J
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology*; D017209:Apoptosis / Q000276:immunology; D015152:Blotting, Northern; D015153:Blotting, Western; D023201:CD40 Ligand / Q000276:immunology*; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D024721:E-Box Elements / Q000187:drug effects; D005434:Flow Cytometry; D016193:G1 Phase / Q000187:drug effects*; D051796:Inhibitor of Differentiation Proteins; D016393:Lymphoma, B-Cell / Q000276:immunology*; D051379:Mice; D009363:Neoplasm Proteins / Q000276:immunology*; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured
D000888:Antibodies, Anti-Idiotypic; D051796:Inhibitor of Differentiation Proteins; D009363:Neoplasm Proteins; C044203:anti-IgM; D023201:CD40 Ligand; C075640:ID3 protein, human