Bis induces growth inhibition and differentiation of HL-60 cells via up-regulation of p27.
Bis (Bag-3, CAIR), a Bcl-2-interacting protein, promotes the anti-apoptotic activity of Bcl-2 and increased levels of Bis have been observed in several disease models. The involvement of Bcl-2 and some Bcl-2-binding proteins in differentiation has recently been reported. However, the relevance of Bis to cellular differentiation remains unknown. The findings herein show that Bis expression is up-regulated during the differentiation of HL-60 cells. To investigate the effect of Bis expression on differentiation, we established Bis-overexpressing HL-60 cells (HL-60-bis). HL-60-bis cells have a low nuclear: cytoplasmic ratio and indented nucleus in Wright- Giemsa staining, and an increased expression of CD11b in immunofluorescence study, indicating the promotion of differentiation. The overexpression of Bis also resulted in a retarded cell growth rate, accompanied by the accumulation of HL-60 cells at the G0/G1 phase of the cell cycle, which was sustained during the differentiation process. Western blot analysis revealed that the expression of p27, a representative inducer of cell cycle arrest at the G1 phase, was increased 2.5-fold in HL-60-bis cells compared to HL-60-neo cells. These results suggest that the Bis induced growth inhibition of HL-60 cells promotes G0/G1 phase arrest via up-regulation of p27, which seems to be a prerequisite for differentiation. Further studies will be required to define the exact roles of Bis on cellular differentiation more precisely.
Seo
Yun Jee
YJ
Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
Jeon
Mi Hee
MH
Lee
Jung Hee
JH
Lee
Yong Joon
YJ
Youn
Ho Joong
HJ
Ko
Jeong Heon
JH
Lee
Jeong Hwa
JH
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation; D049109:Cell Proliferation; D048430:Cell Shape; D002478:Cells, Cultured; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism*; D005434:Flow Cytometry; D015870:Gene Expression; D018922:HL-60 Cells; D006801:Humans; D015854:Up-Regulation
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C414431:BAG3 protein, human; D002352:Carrier Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27