Melanoma is the most common
cancer in young adults, with a constantly increasing incidence. Metastatic
melanoma is a very aggressive
cancer with a 5-year survival rate of about 22-25%. This is, in most cases, due to a lack of
therapies which are effective on the long term. Hence, it is crucial to find new therapeutic agents to increase patient survival.
Toad venoms are a rich source of potentially pharmaceutically active compounds and studies have highlighted their possible effect on
cancer cells. We focused on the
venoms of two different toad species: Bufo bufo and Rhinella marina. We screened the
venom crude extracts, the fractions from
crude extracts and isolated biomolecules by studying their antiproliferative properties on
melanoma cells aiming to determine the compound or the combination of compounds with the highest antiproliferative effect. Our results indicated strong antiproliferative capacities of
toad venoms on
melanoma cells. We found that these effects were mainly due to
bufadienolides that are
cardiotonic steroids potentially acting on the Na+/K+
ATPase pump which is overexpressed in
melanoma. Finally, our results indicated that
bufalin alone was the most interesting compound among the isolated
bufadienolides because it had the highest antiproliferative activity on
melanoma cells.