Influence of 28-O-propynoylbetulin on proliferation and apoptosis of melanotic and amelanotic human melanoma cells.

INTRODUCTION: A relatively new approach in treatment of malignant melanoma is the use of betulin and its synthetic derivatives that have anticancer properties. The aim of the study was to determine the effect of an acetylenic derivative of betulin, 28-O-propynoylbetulin, on cell growth and apoptosis induction in human melanotic and amelanotic melanoma cells.

MATERIALS AND METHODS: The A2058 and C32 cell lines were incubated with 28-O-propynoylbetulin (working solutions from 0.1 to 10 μg/ml). To evaluate cell proliferation, a sulforhodamine B based assay was conducted. In order to elucidate the early stages of apoptosis in both melanoma cell lines, caspase-3 activity was evaluated.

RESULTS: The administration of 28-O-propynoylbetulin at a concentration equal to or less than 1 μg/ml did not cause a statistically significant change in the cell proliferation in either melanoma cell line (compared to control, p>0.05). Higher concentrations of the compound (3 and 10 μg/ml) inhibited the cell growth (in comparison to control, p<0.05). These results corresponded with caspase-3 activity results that revealed an increase of enzyme activity after 24-hour incubation with 3 and 10 μg/ml of the compound (compared to control, p<0.05).

DISCUSSION: The study revealed that 28-O-propynoylbetulin may have diverse effects on melanoma cells and could be a strong inhibitor of cell growth (C32 cells) or exert a more potent proapoptotic effect (A2058 cells). These findings support the possibility of the use of EB5 in different antimelanoma approaches.