Fig. 5.

Synergistic in vitro cytotoxic effect of BSI-401 and oxaliplatin in combination on COLO357FG and MiaPaCa-2 pancreatic cancer cells. A,D, Relative effect of BSI-401, oxaliplatin, or both on tumor cells growth. On day 0, COLO357FG and MiaPaCa-2 cell lines were seeded at a density of 1.0 × 10³ cells/well. On the following day, the cells were treated with increasing doses of BSI-401, oxaliplatin, or their combination. On day 2, the medium containing drugs was removed, the cells were washed twice with phosphate-buffered saline, and fresh medium was added. After 5 days of incubation, the relative variable cell numbers was determined. Dimethyl sulfoxide-treated cells were assigned a value of 0%. Means and SE of three independent experiments performed in triplicate are shown. B,E, CI plot, representing a quantitative measure of the degree of drug interaction for a given endpoint of the effect measurement. The CI values of <1, 1, and >1 indicate synergy, additivity and antagonism, respectively. Each point is the mean of at least tree different replicate experiments. C,F, Measurement of apoptosis by DNA fragmentation. On day 0, COLO357FG and MiaPaCa-2 cell lines were seeded at a density of 5 × 10⁶ cells/dish. On the following day, the cells were treated with BSI-401 5 μM, oxaliplatin 5 μM, their combination, or dimethyl sulfoxide as control. On day 2, the cells were collected, the DNA was extracted, and the fragmented DNA detected by agarose gel electrophoresis.