A-431) and 6.89lg/ml (on SK-MEL-28) after 48-h treatment with
MPEE.
After 48 h treatment, morphological alterations in both cell
lines were observed compared with the untreated cells (Fig. 2). Untreated cells were polygonal in ordinary shape, while treated cells,
especially after treatment with 10lg/ml of MPEE, were shown to
be retracted and rounding in shape with some cells detached from
the surface and floating in the media.
Significant decreases in cell viability were observed after treatment with the positive controls of 5-FU and DTIC (data not shown).
The 50% effective concentration (EC50) values are summarized in
Table 3.EC50value for DTIC treatment could not be obtained for
SK-MEL-28 cell line due to potential solvent effects (DTIC was dissolved in 0.02 N acetic acid). The maximum concentration possible
to use without significantly altering the cell culture medium pH
was 100lg/ml. At this concentration of DTIC, 25% cell killing was
observed on SK-MEL-28 cell lines, which was consistent with a
previous study (Lillehammer et al., 2007). Additionally, 5-FU and
DTIC showed similar toxicity on both cancer and normal cells as
evidenced by similar EC50values on both cancer and normal cell
lines.