Figure 3. ABT -737–induced apoptosis in HCT116 tumor spheroids.

(A) HCT116 cells were grown as spheroids, and serial sections were stained for GLUT1 or HIF-1α and then the appropriate secondary antibody or isotype negative as described in Methods. Scale bar: 500 μm. (B) Spheroids were treated with ABT-737 at IC₂₀ (2.8 μM) or IC₉₀ (14.4 μM) for 24 hours as described in Methods. DAPI: blue; GLUT-1: green; CC3: red. Data are representative of 3 independent experiments (n > 12 for both drug-treated and untreated spheroids). Scale bar: 500 μm.