Mcl-1 mediates cytokine deprivation induced apoptosis of human myeloma cell line XG-7.
OBJECTIVE
To investigate apoptosis in XG-7, a human myeloma cell line, induced by IL-6 deprivation and the function of three anti-apoptotic Bcl-2 proteins (Bcl-2, Bcl-kappa(L), Mcl-1) in the apoptotic process.


METHODS
Apoptosis in XG-7 myeloma cells induced by IL-6 withdrawal was determined by flow cytometry with propidium iodide (PI) nuclear staining. Expressions of three Bcl-2 proteins in XG-7 cells were monitored by immunoblotting assay.


RESULTS
In the absence of IL-6 for a certain time, a significant percentage of apoptiotic XG-7 cells can be observed, as well as down-regulated expression of one of the three anti-apoptotic proteins (Mcl-1) in XG-7 cells. IL-6 re-stimulation in XG-7 cells following cytokine removal up-regulated the expression of Mcl-1 and inhibited cell apoptosis.


CONCLUSIONS
Mcl-1,instead of Bcl-2 and Bcl-kappa(L), plays an important role in IL-6 deprivation induced apoptosis in XG-7 human myeloma cells.
Song
Lun
L
Department of Molecular Immunology, Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Beijing 100850, China. lunsong@yahoo.com
Li
Yan
Y
Sun
Yingxun
Y
Shen
Beifen
B
D017209:Apoptosis; D006801:Humans; D015850:Interleukin-6 / Q000502:physiology*; D009101:Multiple Myeloma / Q000473:pathology*; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000032:analysis / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D014407:Tumor Cells, Cultured; D051020:bcl-X Protein
C494811:BCL2L1 protein, human; D015850:Interleukin-6; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein