B cell receptor-induced growth arrest and apoptosis in WEHI-231 immature B lymphoma cells involve cyclic AMP and Epac proteins

ABSTRACTWhile CD95 is an apoptosis-inducing receptor and has emerged as a potential anticancer therapy target, mounting evidence shows that CD95 is also emerging as a tumor promoter by activating nonapoptotic signaling pathways. Gammaherpesviral infection is closely associated with lymphoproliferative diseases, including B cell lymphomas. The nonapoptotic function of CD95 in gammaherpesvirus-associated lymphomas is largely unknown. Here, we show that stimulation of CD95 agonist antibody drives the majority of sensitive gammaherpesvirus-transformed B cells to undergo caspase-dependent apoptosis and promotes the survival and proliferation of a subpopulation of apoptosis-resistant B cells. Surprisingly, CD95-mediated nonapoptotic signaling induced beta interferon (IFN-β) expression and correlatively inhibited B cell receptor (BCR)-mediated gammaherpesviral replication in the apoptosis-resistant lymphoma cells without influencing BCR signaling. Further analysis showed that IFN-β alone or synergizing with CD95 blocked the activation of lytic switch proteins and the gene expression of gammaherpesviruses. Our findings indicate that, independent of its apoptotic activity, CD95 signaling activity plays an important role in blocking viral replication in apoptosis-resistant, gammaherpesvirus-associated B lymphoma cells, suggesting a novel mechanism that indicates how host CD95 prototype death receptor controls the life cycle of gammaherpesviruses independent of its apoptotic activity.IMPORTANCEGammaherpesviruses are closely associated with lymphoid malignancies and other cancers. Viral replication and persistence strategies leading to cancer involve the activation of antiapoptotic and proliferation programs, as well as evasion of the host immune response. Here, we provide evidence that the stimulation of CD95 agonist antibody, mimicking one of the major mechanisms of cytotoxic T cell killing, inhibits B cell receptor-mediated gammaherpesviral replication in CD95 apoptosis-resistant lymphoma cells. CD95-induced type I interferon (IFN-β) contributes to the inhibition of gammaherpesviral replication. This finding sheds new light on the CD95 nonapoptotic function and provides a novel mechanism for gammaherpesviruses that helps them to escape host immune surveillance.

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Roles of the Tumor Suppressor p53 and the Cyclin-dependent Kinase Inhibitor p21WAF1/CIP1 in Receptor-mediated Apoptosis of WEHI 231 B Lymphoma Cells

Journal of Experimental Medicine ◽

10.1084/jem.187.10.1671 ◽

1998 ◽

Vol 187 (10) ◽

pp. 1671-1679 ◽

Cited By ~ 35

Author(s):

Min Wu ◽

Robert E. Bellas ◽

Jian Shen ◽

Gail E. Sonenshein

Keyword(s):

Tumor Suppressor ◽

B Cell ◽

Kinase Inhibitor ◽

Ectopic Expression ◽

Cyclin Dependent Kinase ◽

Lymphoma Cells ◽

B Lymphoma ◽

Cyclin Dependent Kinase Inhibitor ◽

B Lymphoma Cells ◽

Wehi 231

Treatment of WEHI 231 immature B lymphoma cells with an antibody against their surface immunoglobulin M (anti-IgM) induces apoptosis and has been studied extensively as a model of self-induced B cell tolerance. Since the tumor suppressor protein p53 has been implicated in apoptosis in a large number of cell types and has been found to be mutated in a variety of B cell tumors, here we sought to determine whether p53 and the p53 target gene cyclin-dependent kinase inhibitor p21WAF1/CIP1 were involved in anti-IgM–induced cell death. Anti-IgM treatment of WEHI 231 cells increased expression of p53 and p21 protein levels. Ectopic expression of wild-type p53 in WEHI 231 cells induced both p21 expression and apoptosis. Ectopic expression of p21 similarly induced apoptosis. Rescue of WEHI 231 cells from apoptosis by costimulation with CD40 ligand ablated the increase in p21 expression. Lastly, a significant decrease in anti-IgM–mediated apoptosis was seen upon downregulation of endogenous p53 activity by expression of a dominant-negative p53 protein or upon microinjection of an antisense p21 expression vector or antibody. Taken together, the above data demonstrate important roles for p53 and p21 proteins in receptor-mediated apoptosis of WEHI 231 B cells.

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Altered B-cell receptor signaling kinetics distinguish human follicular lymphoma B cells from tumor-infiltrating nonmalignant B cells

Blood ◽

10.1182/blood-2006-02-003921 ◽

2006 ◽

Vol 108 (9) ◽

pp. 3135-3142 ◽

Cited By ~ 109

Author(s):

Jonathan M. Irish ◽

Debra K. Czerwinski ◽

Garry P. Nolan ◽

Ronald Levy

Keyword(s):

B Cells ◽

Cell Signaling ◽

Follicular Lymphoma ◽

B Cell ◽

Cell Receptor ◽

B Cell Receptor ◽

Lymphoma Cells ◽

B Lymphoma Cells ◽

Bcr Signaling ◽

B Cell Subsets

Abstract The B-cell receptor (BCR) transmits life and death signals throughout B-cell development, and altered BCR signaling may be required for survival of B-lymphoma cells. We used single-cell signaling profiles to compare follicular lymphoma (FL) B cells and nonmalignant host B cells within individual patient biopsies and identified BCR-mediated signaling events specific to lymphoma B cells. Expression of CD20, Bcl-2, and BCR light chain isotype (κ or λ) distinguished FL tumor B-cell and nontumor host B-cell subsets within FL patient biopsies. BCR-mediated signaling via phosphorylation of Btk, Syk, Erk1/2, and p38 occurred more rapidly in tumor B cells from FL samples than in infiltrating nontumor B cells, achieved greater levels of per-cell signaling, and sustained this level of signaling for hours longer than nontumor B cells. The timing and magnitude of BCR-mediated signaling in nontumor B cells within an FL sample instead resembled that observed in mature B cells from the peripheral blood of healthy subjects. BCR signaling pathways that are potentiated specifically in lymphoma cells should provide new targets for therapeutic attention.

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CD40 Ligand Rescues Inhibitor of Differentiation 3-Mediated G1 Arrest Induced by Anti-IgM in WEHI-231 B Lymphoma Cells

Proceedings of the Royal Society of Medicine ◽

10.1177/003591572301601234 ◽

1923 ◽

Vol 16 (Otol_Sect) ◽

pp. 2453-2461

Author(s):

Kikumi Hata ◽

Takayuki Yoshimoto ◽

Junichiro Mizuguchi

Keyword(s):

Cell Cycle Progression ◽

Growth Arrest ◽

Binding Activity ◽

G1 Arrest ◽

Lymphoma Cells ◽

B Lymphoma ◽

Helix Loop Helix ◽

B Lymphoma Cells ◽

Wehi 231 ◽

E Box

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 G1 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 G1 phase, which was accompanied by reduced levels of cyclin D2, cyclin E, and cyclin A, and a reciprocal up-regulation of p27Kip1. 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 G1 arrest in WEHI-231 cells.

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Lymphoma models for B cell activation and tolerance. III. Cell cycle dependence for negative signalling of WEHI-231 B lymphoma cells by anti-mu.

Journal of Experimental Medicine ◽

10.1084/jem.164.1.156 ◽

1986 ◽

Vol 164 (1) ◽

pp. 156-164 ◽

Cited By ~ 73

Author(s):

D W Scott ◽

D Livnat ◽

C A Pennell ◽

P Keng

Keyword(s):

Cell Cycle ◽

B Cell ◽

Cell Activation ◽

S Phase ◽

B Cell Activation ◽

Lymphoma Cells ◽

B Lymphoma ◽

B Lymphoma Cells ◽

Wehi 231 ◽

G1 Cells

WEHI-231 B lymphoma cells have proven to be a useful model for the regulation of growth of normal B cells by anti-Ig reagents. We previously reported that the growth of these lymphoma cells is inhibited by heterologous or monoclonal anti-mu or anti-kappa reagents. Such cells cease to incorporate thymidine within 24-48 h of exposure to anti-Ig reagents, but are not adversely affected by antibodies directed at either class I or class II histocompatibility antigens. In fact, cell cycle analysis revealed that anti-mu causes a block in the transition of these cells from G1 to S phase. To further study the mechanism of growth inhibition, we have purified lymphoma cells in G1 by centrifugal elutriation, or enriched WEHI-231 cells at the G1/S interface by treatment with hydroxyurea, and followed their progression through the cell cycle in the presence or absence of anti-mu. Our data show that WEHI-231 B lymphoma cells receive a negative signal early in G1, since delayed addition of anti-mu (to late G1 cells) leads to no alteration in cell cycle progression at 24 h, and exposure to anti-mu during S does not alter progress through DNA synthesis and mitosis. Moreover, exposure to anti-mu for only 2 h prevents purified G1 cells from entering their first S phase. The nature of the relevant processes in early G1 is discussed in terms of models of B cell activation and tolerance induction.

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