Figure 3

(A) The HDAC-inhibitory activity of VA in H460, TE12 and H513 cells. Cells were treated with VA (0.5, 1.0 and 5.0 mM) for 12 h and hyperacetylated H3 and H4 histone proteins were determined by Western blot analysis. Mild growth-inhibitory effect of VA on cultured thoracic cancer cells. Cells, seeded in 96-well microtiter plates, were continuously exposed to VA (0.62–10.0 mM) for 96 h. Cell viability was measured by MTT (4,5-dimethylthiazo-2-yl)-2,5-diphenyl tetrazolium bromide) and cell viability was expressed as percentages of untreated control cells. Data are expressed as mean±s.e.m. of three independent experiments. (B) Cell cycle arrest at G1/S checkpoint with accumulation of cells at G0/G1, little induction of apoptosis only at high concentrations of VA (5 mM) for 48 h. (C) Mild but statistically significant induction of apoptosis of cultured thoracic cancer cells was only observed following exposure to high concentration of VA (5.0 mM; # or +P<0.05–0.01 vs control cells or VA (1mM)-treated cells, respectively, by ANOVA and pairwise comparison by Bonferroni test). Cells were continuously treated with VA at either 1.0 or 5.0 mM for 48 h and harvested for quantitation of apoptosis by the TUNEL-based ApoBrdU assay and flow cytometry. Data are expressed as mean±s.e.m. of three independent experiments.