title: The Bcl-2 family member Bfl-1/A1 is strongly repressed in normal and malignant plasma cells but is a potent anti-apoptotic factor for myeloma cells.
abstract: Terminal B-cell differentiation is a multi-step process, from short-lived plasmablasts to mature long-lived plasma cells (PC). The anti-apoptotic Bcl-2 family member Bfl-1/A1 plays a critical role in the survival of mature B cells. However, its potential involvement at the later stages of B-cell development remains highly controversial. Our aim was thus to clarify the place of Bfl-1/A1 in the biology of normal PC and in the pathogenesis of multiple myeloma (MM), the major PC dyscrasia. Using gene expression profiling and quantifiable reverse transcription polymerase chain reaction experiments, we found a similar down-regulation of Bfl-1/A1 in both normal immature plasmablasts and mature PC when compared with B cells. In myeloma cells, the level of Bfl-1/A1 was low and Bfl-1/A1 was not a nuclear factor kappaB-inducible gene. Collectively, these data demonstrate that Bfl-1/A1 is not involved in the prolonged survival of normal mature PC, and that Bfl-1/A1 deregulation is not a common oncogenic event in MM. However, overexpression of Bfl-1/A1 by retroviral transduction promoted autonomous survival of an interleukin-6-dependent myeloma cell line and rendered it less sensitive to dexamethasone. Thus, Bfl-1/A1 transduction could be an interesting tool to obtain myeloma cell lines from primary samples and to favour the in vitro generation of antibody-secreting, long-lived normal PC.
authors.affiliation: INSERM U475, Rue Puech Villa, Montpellier, France.
authors.forename: Karin
authors.initials: K
authors.lastname: Tarte
authors.forename: Michel
authors.initials: M
authors.lastname: Jourdan
authors.forename: Jean Luc
authors.initials: JL
authors.lastname: Veyrune
authors.forename: Ingolf
authors.initials: I
authors.lastname: Berberich
authors.forename: Geneviève
authors.initials: G
authors.lastname: Fiol
authors.forename: Nicole
authors.initials: N
authors.lastname: Redal
authors.forename: John
authors.initials: J
authors.lastname: Shaughnessy
authors.forename: Bernard
authors.initials: B
authors.lastname: Klein
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D015536:Down-Regulation; D006801:Humans; D015850:Interleukin-6 / Q000494:pharmacology; D015778:Minor Histocompatibility Antigens; D009101:Multiple Myeloma / Q000378:metabolism* / Q000473:pathology; D009363:Neoplasm Proteins / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010950:Plasma Cells / Q000187:drug effects / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured
chemical_list: C096816:BCL2-related protein A1; D015850:Interleukin-6; D015778:Minor Histocompatibility Antigens; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D003907:Dexamethasone