Lyn tyrosine kinase signals cell cycle arrest but not apoptosis in B-lineage lymphoma cells.

Abstract

Signal transduction initiated by binding of antibodis to cell surface molecules can have an important impact on the growth of tumor cells. (8), the effectiveness of anti-CD19 antibodies in preventing tumor growth probably results from a signal transduction phenomenon similar to that observed for anti-immunoglobulin (antiIg) on BCL1, rather than a classical antibody-mediated effector function, e.g., antibody-dependent cellular cytotoxicity.Here we show that anti-Ig induces an antiproliferative response in a subclone of BCL1, BCL1.3B3 (9), that includes the induction of cell cycle arrest and apoptosis. Treatment of BCL1.3B3 cells with specific antisense oligonucleotides results in the depletion of the Lyn tyrosine kinase protein.When depleted cells are challenged with anti-Ig, apoptosis is still induced, but cell cycle arrest is not. The same result is observed in anti-Ig-treated Daudi lymphoma cells. In addition, antisense lyn can prevent cell cycle arrest induced by the cross-linking ofCD19. These results indicate that the Lyn tyrosine kinase is required for transduction of the cell cycle arrest signal initiated by cross-linking of mlg or CD19. MATERIALS AND METHODSAntibodies and Antsens Olguclides. BCL1.3B3 cells were cultured in RPMI 1640 medium with 5% (vol/vol) fetal calf serum. Antibody preparations (7,8,10,11) were affinitypurified and included rabbit anti-ovalbumin (35 pg/ml), rabbit anti-BCL, idiotype (35 pg/ml), goat anti-human IgM (7.5 pg/ml), goat anti-ovalbumin (7.5 mg/ml), and anti-CD19 (HD37; 350 pg/ml).Cells were plated with antisense oligonucleotides 24 hr before the addition of antibody. Oligonucleotides were phosphorothioate derivatives synthesized by Oligos Etc. (Guilford, CT). For the BCL,.3B3-cell experiments, the sequences TG-

BCR-ABL independence and LYN kinase overexpression in chronic myelogenous leukemia cells selected for resistance to STI571

“…Phosphorothioate antisense oligodeoxynucleotide LYN sequence (Lyn-AS), as previously described, 27,28 and a sense oligomer representing the first 7 codons of the LYN gene (Lyn S1; complementary to Lyn-AS) were used in these studies (Sigma-Genosys). To examine cellular effects of oligomers, 20 000 cells growing in 96-well plates in RMPI 1640 media with 10% fetal bovine serum were treated with 20 M oligomer for 24 hours.…”

Association of Lyn Tyrosine Kinase with the Nuclear Matrix and Cell‐Cycle‐Dependent Changes in Matrix‐Associated Tyrosine Kinase Activity

“…Upon activation, Lyn polypeptides associate with the cell-cycle-regulating kinase pi4cdc2, resulting in increased tyrosine phosphorylation (on Tyrl5) and a decrease in its kinase activity. Scheuermann et al [45] used antisense oligonucleotides to demonstrate that Lyn is required for antiIg-mediated cell-cycle arrest in mouse B-cell lymphoma cells, suggesting that this enzyme may be an important mediator or regulator of cell-cycle arrest at least in some cells.…”

Altered antigen receptor signaling and impaired Fas-mediated apoptosis of B cells in Lyn-deficient mice.

“…A Lyn-deficient mutant of the chicken B cell line DT40, generated through homologous recombination, exhibited delayed Ca 2+ influx but enhanced inositol 1,4,5-triphosphate (IP3) accumulation, indicating that Lyn regulates Ca 2+ mobilization through a process independent of IP 3 generation (31). Moreover, using antisense oligonucleotides, Lyn was shown to be required for anti-lgM-mediated cell cycle arrest in both murine BCL1 and human Daudi cell lines (32). These observations suggest a role for Lyn in the negative regulation of BCR signaling.…”