Figure 1. Impacts of DAC treatment on EL4 tumorigenicity and tumor growth.

(A) EL4 cells were treated with DAC (0.25 µM in culture medium) or Cytidine or PBS for 72 h. Cells were then injected into each mouse s.c. at a dose of 1×10⁴ cells/mouse. Tumor size was measured in two directions every two or three days. Tumor volume was calculated using a formula: volume = (L x W²)/2 where L = length; W = width. *P<0.05 when DAC-treatment is compared to PBS or Cytidine treatment. Five to six mice were used in each group and data were pooled from two experiments. (B) EL4 cells treated with DAC were injected into C57BL/6 mice s.c. at a dose of 1×10⁴ cells/mouse (G1), 8×10⁴ cells/mouse (G2) or 16×10⁴ cells/mouse (G3). PBS-treated EL4 cells (1×10⁴ cells/mouse) served as control. Mouse survival data is shown. Five mice were included in each group and data shown are representative of three independent experiments. (C) DAC-treated or PBS-treated EL4 cells were injected into each mouse i.v. at a dose of 1×10⁴ cells/mouse. Mouse survival was monitored up to 100 days after tumor cell injection. Ten mice per group were used, and data shown are representative of three independent experiments. (D) Mice with established EL4 tumors were treated with DAC or PBS i.p. for 5 consecutive days starting on day 10. Data shown are representative of three experiments. Asterisks indicate statistical significance of P<0.05.