title: [Function of alternative NF-κB activity in B-cell chronic lymphocytic leukemia cells].
abstract: OBJECTIVE
  To investigate the function of alternative NF-κB activity in B-cell chronic lymphocytic leukemia cells (B-CLL).
  
  
  METHODS
  The mRNA expression of individual NF-κB subunits in CD5⁺CD19⁺ cells (CLL B-cells) from bone marrow (BM) of 56 patients with B-CLL was analyzed by quantitative RT-PCR. An ELISA-based NF-κB family transcription factor activity assay was performed to quantify the κB DNA-binding activity in nuclear extracts from CLL B-cells. Cell death of CLL-B cells was determined by PI staining, RelA and RelB expression at protein level of CLL B-cells by Western blot analyses.
  
  
  RESULTS
  The expression levels of RelA, p50, RelB and p52 mRNA in CLL B-cells were all higher than that of normal B cells with statistical significance (P<0.05). RelA was activated in almost all the patients detected while RelB activity was induced in part of samples. The average RelA activity in CLL B-cells was increased compared to that in normal B cells while the average RelB activity was similar to that of normal B cells. When cultured in vitro for 24, 48 and 72 hours, the frequencies of cell death of CLL B-cells from RelA⁺/RelB⁻ group were(35.54±4.43)%,(50.92±8.44)%, and(49.24±8.16)%, respectively; that of the RelA⁺/RelB⁺ group were (20.65±2.37)%, (18.17±1.36)%, and (26.55±4.08)%, respectively. When the cells from RelA+/RelB⁻ group were co-cultured with bone marrow stromal cells (hBMSCs), the frequencies of cell death of CLL B-cells were decreased compared to that of the cells cultured alone, while the frequencies of cell death of RelA⁺/RelB⁻ CLL B-cells were higher than that of CLL B-cells from RelA⁺/RelB⁺ group when co-cultured with hBMSCs. RelA and RelB expression in CLL-B cells from the RelA⁺/RelB⁻ group was induced after co-cultured with hBMSCs for 48 h. RelB was reduced in the cytoplasm and increased in the nucleus in CLL-B cells from the RelA+/RelB+ group.
  
  
  CONCLUSIONS
  The alternative NF-κB was indeed activated and presented heterogeneous in CLL B-cells from BM. Activation of RelB combined with RelA activity could provide the survival advantage to CLL B-cells from BM. Co-culture with hBMSCs could protect CLL-B cells through the induction of RelA and Rel B expressions.
authors.affiliation: Central Lab, The First Affiliated Hospital of Soochow University, Suzhou 215006, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Xu
authors.affiliation: Central Lab, The First Affiliated Hospital of Soochow University, Suzhou 215006, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.affiliation: Central Lab, The First Affiliated Hospital of Soochow University, Suzhou 215006, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Guo
mesh_terms: D016022:Case-Control Studies; D002467:Cell Nucleus / Q000378:metabolism; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000378:metabolism*; D052002:NF-kappa B p50 Subunit / Q000378:metabolism; D052003:NF-kappa B p52 Subunit / Q000378:metabolism; D051996:Transcription Factor RelA / Q000378:metabolism*; D051841:Transcription Factor RelB / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D052002:NF-kappa B p50 Subunit; D052003:NF-kappa B p52 Subunit; C489548:NFKB1 protein, human; C498206:NFKB2 protein, human; C498143:RELA protein, human; C497593:RELB protein, human; D051996:Transcription Factor RelA; D051841:Transcription Factor RelB