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Granulocytic differentiation of HL‐60 cells results in spontaneous apoptosis mediated by increased caspase expression
Author(s) -
Watson R.William G,
Rotstein Ori D,
Parodo Jean,
Bitar Richard,
Hackam David,
Marshall John C
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00779-5
Subject(s) - apoptosis , retinoic acid , caspase , microbiology and biotechnology , messenger rna , chemistry , blot , biology , programmed cell death , cell culture , gene , biochemistry , genetics
HL‐60 cells differentiating into neutrophil‐like cells die an apoptotic death in vitro. Susceptibility to apoptosis is associated with decreased Bcl‐2 protein and mRNA expression; however, the effect of differentiation on the expression of pro‐apoptotic caspases is unknown. Spontaneous apoptosis occurred 6 days after retinoic acid treatment. Western blotting showed loss of Bcl‐2 by day 7, and new expression of ICE (caspase 1) and CPP32 (caspase 3) protein by day 2. Northern analysis demonstrated loss of Bcl‐2 mRNA and increases in ICE mRNA by day 2; CPP32 mRNA was unchanged. Differential Bcl‐2 and ICE mRNA expression was also found when granulocytic differentiation was stimulated by DMSO. Differentiated HL‐60 cell lysates exhibited functional ICE proteolytic activity. De novo caspase expression was responsible for the development of spontaneous apoptosis, since specific inhibitors of ICE (YVAD‐CMK) and CPP32 (DEVD‐CHO), inhibited retinoic acid induced spontaneous apoptosis. Functional maturation and susceptibility to apoptosis are both inducible and linked in this granulocyte precursor cell line.