AR-12 has no effect on the accumulation of gentamicin-FITC in RAW264.7 macrophages. Cells were treated with gentamicin-FITC (10 μg/ml), alone or in combination with AR-12 (1 μM), for 24, 72, or 120 h. After treatment, cellular accumulations of gentamicin-FITC were examined with fluorescence microscopy.