AG490 reduces cell growth of HTLV-1-infected T-cell lines and primary ATL cells. (A) HTLV-1-infected T-cell lines (5 × 104/mL) were treated with 0, 25 or 50 μM AG490 for 24 or 48 h. Cell numbers were counted in triplicate by Trypan blue dye exclusion method. Data are expressed as the mean values of viable cell numbers. (B) Primary ATL cells from seven patients (ATL #1–7) and PBMCs from three healthy donors (Normal #1–3) were treated with 0, 25 or 50 μM AG490 for 48 h. Cell growth was assessed by the WST-8 method. Data are expressed as the percentages of control (untreated cells). (C) Cell-cycle analysis of HTLV-1-infected T-cell lines treated with AG490. Cells were treated in the absence (-) or presence (+) of 25 μM AG490 for 24 h. DNA content was analyzed by flow cytometry with propidium iodide staining. G1, S and G2/M indicate the stages of the cell-cycle. Data represent mean percentages of cells at each cell-cycle from three independent experiments. (D) Induction of apoptosis in HTLV-1-infected T-cell lines by AG490. Cells were treated in the absence (open bar) or presence (solid bar) of 50 μM AG490 for 48 h and stained with Annexin-V. Apoptosis was analyzed by flow cytometry. Data represent mean percentages of apoptotic cells from three independent experiments.