FIGURE 2.

BITC, PEITC, and SFN induce cell cycle arrest and apoptosis in A549 cells. A, histograms of ITC-treated cells indicating that 10 μm BITC, 10 μm PEITC, and 30 μm SFN induce substantial G₂/M arrest (increase of the second peak), whereas 10 μm SFN induce G₁ arrest. B, substantial amounts of mitotic cells were detected after treatments with 10 μm BITC, 10 μm PEITC, and 30 μm SFN for 24 h but not in cells treated with 10 μm SFN. The mitotic cells are identified as having a tetraploid DNA content and a high level of phosphorylated histone 3 as indicated in Gate 3. Gate 1 contains cells with diploid DNA, whereas Gate 2 contains cells with tetraploid DNA and low level of phospho-H3. Numbers in the upper right corners indicate percentages of mitotic cells in each sample. C, induction of apoptosis was indicated by increases in the relative size of sub-G₁ fractions of cells (left) and increased caspases-3 activities (right) in cells treated with 10 μm BITC (⋄), 10 μm PEITC (□), and 30 μm SFN (×) but not in 10 μm SFN (▵) and DMSO (•).