Dose-dependent effects of PAC on proliferation and morphology. Cells were plated in 96-well assay plates in media with FBS. The upper row (A-E) was grown without PAC, the mid-level row (F-J) in the presence of PAC at 20 μg/mL, and the lower row (K-O) under PAC administration at 50 μg/mL. All cell lines exhibited a dose-dependent response to PAC administration, with higher doses resulting in fewer cells at day 4. Ca Ski (A), CAL 27 (C), CAL 27-TF16 (D) and Hs27 (E) cells were reduced in number with PAC at 20 μg/mL (F, H, I, J), unlike GH354 cells (B), which experienced a reduction in proliferation, and morphological changes indicative of apoptosis (G). Cellular proliferation was reduced by PAC in all cell lines (K-O) at 50 μg/mL; all cell lines exhibited altered morphology, except Hs27 (O) cells which appeared normal, although fewer in number.