title: Bis induces growth inhibition and differentiation of HL-60 cells via up-regulation of p27.
abstract: 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.
authors.affiliation: Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
authors.forename: Yun Jee
authors.initials: YJ
authors.lastname: Seo
authors.forename: Mi Hee
authors.initials: MH
authors.lastname: Jeon
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Yong Joon
authors.initials: YJ
authors.lastname: Lee
authors.forename: Ho Joong
authors.initials: HJ
authors.lastname: Youn
authors.forename: Jeong Heon
authors.initials: JH
authors.lastname: Ko
authors.forename: Jeong Hwa
authors.initials: JH
authors.lastname: Lee
mesh_terms: 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
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C414431:BAG3 protein, human; D002352:Carrier Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27