title: IL-4 protects the B-cell lymphoma cell line CH31 from anti-IgM-induced growth arrest and apoptosis: contribution of the PI-3 kinase/AKT pathway.
abstract: Interleukin-4 (IL-4) promotes lymphocyte survival and protects primary lymphomas from apoptosis. Previous studies reported differential requirements for the signal transducer and activator of transcription 6 (STAT6) and IRS2/phosphatidylinositol 3 kinase (PI-3K) signaling pathways in mediating the IL-4-induced protection from Fas-mediated apoptosis. In this study, we characterized IL-4-activated signals that suppress anti-IgM-mediated apoptosis and growth arrest of CH31, a model B-cell lymphoma line. In CH31, anti-IgM treatment leads to the loss of mitochondrial membrane potential, phospho-Akt, phospho-CDK2, and c-myc protein. These losses are followed by massive induction of p27(Kip1) protein expression, cell cycle arrest, and apoptosis. Strikingly, IL-4 treatment prevented or reversed these changes. Furthermore, IL-4 suppressed the activation of caspases 9 and 3, and, in contrast to previous reports, induced the phosphorylation (deactivation) of BAD. IL-4 treatment also induced expression of BclxL, a STAT6-dependent gene. Pharmacologic inhibitors and dominant inhibitory forms of PI-3K and Akt abrogated the anti-apoptotic function of IL-4. These results suggest that the IL-4 receptor activates several signaling pathways, with the Akt pathway playing a major role in suppression of the apoptotic program activated by anti-IgM.
authors.affiliation: Program in Oncology, Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Carey
authors.forename: Elena
authors.initials: E
authors.lastname: Semenova
authors.forename: Xiulan
authors.initials: X
authors.lastname: Qi
authors.forename: Achsah D
authors.initials: AD
authors.lastname: Keegan
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001402:B-Lymphocytes / Q000201:enzymology; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004791:Enzyme Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism*; D015847:Interleukin-4 / Q000494:pharmacology*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D016393:Lymphoma, B-Cell / Q000201:enzymology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc; D019948:Receptors, Interleukin-4 / Q000819:agonists / Q000378:metabolism; D050800:STAT6 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D051025:bcl-Associated Death Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
chemical_list: D000906:Antibodies; D053148:Caspase 3; D053453:Caspase 9; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004791:Enzyme Inhibitors; D007075:Immunoglobulin M; D015847:Interleukin-4; D047908:Intracellular Signaling Peptides and Proteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D016271:Proto-Oncogene Proteins c-myc; D019948:Receptors, Interleukin-4; D050800:STAT6 Transcription Factor; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; C494819:BAD protein, human; C494811:BCL2L1 protein, human; C436291:CDKN1B protein, human; C508598:IL4 protein, human; C489427:MYC protein, human; C494101:STAT6 protein, human