Fig. 1.

The combination of 5-aza-CdR and physiological levels of vitamin C inhibits cell growth and enhances apoptosis. (A) Population-doubling time after treatment with PBS, vitamin C, 5-aza-CdR, or the combination. HCT116 and HL60 cells were treated with one dose of 300 nM 5-aza-CdR for 24 h; MCF7, SNU398, and HepG2 cells were treated with three consecutive daily doses of 5-aza-CdR at 100 nM, with drug withdrawal at 72 h. All cells were treated with daily doses of 57 μM vitamin C. Values are mean ± SD of three independent experiments. *P < 0.05 by paired Student’s t test comparing combination vs. 5-aza-CdR treatment. (B) Apoptosis analysis showing an increased percentage of apoptotic cells after combination treatment relative to either 5-aza-CdR or vitamin C alone. Cells were stained with annexin V-FITC and PI and were analyzed by flow cytometry.