![Fig. 2. TPA-induced differentiation of U937 cells is associated with caspase activation. / U937 cells were treated with 20 nM TPA for indicated times. (A) Adhesion of cells to the culture flasks (mean ± SD of 3 independent experiments). (B) Flow cytometry analysis of CD11b expression on the plasma membrane (1 representative of 3 experiments). (C) DEVD-AMC, VDVAD-AFC, IETD-AFC, and LEHD-AFC peptide cleavage activity in TPA-treated cells (mean ± SD of 3 independent experiments in triplicate). (D) Flow cytometry analysis of caspase-3 active fragments using a cell-signaling Ab (white curves indicate untreated cells; gray curves, TPA-treated cells; dashed line, control immunoglobulin G [IgG]). (E) Western blot analysis of caspase-3 in whole-cell extracts. VP16 indicates U937 cells exposed to 50 μM etoposide for 4.5 hours. Numbers on the right indicate molecular weight in kilodaltons; *indicates cleavage products.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/100/13/10.1182_blood-2002-06-1778/4/h82423547002.jpeg?Expires=1735833178&Signature=Fz~V~KoAb4~1bJ6p3~sYMKiHin-iWBMjYSqUIyKHchb~4l9vx1S1NOU6BC~IcfxVtlu~9raiAnm0UrjTfNqayPB4lK6SbwvP2Ztx9c7ymyVJdlk6sbe7NzU7ES-6-p~Cmh6EGn2qeok3z7obX-PoyjYJUwA09dsZwjnjD1mNVopOqhgFCjSX3ZxBY76QGc8RguTZ-pz0PWoE8DZdSTl1M-utx3P-w7uN68ZB78bSo2tRInZpJlqE4olxg5LbF8tSnHdUbjv9~0m~zOVQ1ec1~gpYulY2H-v~GuPcRlg4ZgUX3GSqnd83LKZhO~HCZMIDhJJW~ak1ECfdyB0CKpN8WQ__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
TPA-induced differentiation of U937 cells is associated with caspase activation.
U937 cells were treated with 20 nM TPA for indicated times. (A) Adhesion of cells to the culture flasks (mean ± SD of 3 independent experiments). (B) Flow cytometry analysis of CD11b expression on the plasma membrane (1 representative of 3 experiments). (C) DEVD-AMC, VDVAD-AFC, IETD-AFC, and LEHD-AFC peptide cleavage activity in TPA-treated cells (mean ± SD of 3 independent experiments in triplicate). (D) Flow cytometry analysis of caspase-3 active fragments using a cell-signaling Ab (white curves indicate untreated cells; gray curves, TPA-treated cells; dashed line, control immunoglobulin G [IgG]). (E) Western blot analysis of caspase-3 in whole-cell extracts. VP16 indicates U937 cells exposed to 50 μM etoposide for 4.5 hours. Numbers on the right indicate molecular weight in kilodaltons; *indicates cleavage products.
