A Fucose-Containing Sulfated Polysaccharide from Spatoglossum schröederi Potentially Targets Tumor Growth Rather Than Cytotoxicity: Distinguishing Action on Human Melanoma Cell Lines.

Natural substances are strategic candidates for drug development in cancer research. Marine-derived molecules are of special interest due to their wide range of biological activities and sustainable large-scale production. Melanoma is a type of skin cancer that originates from genetic mutations in melanocytes. BRAF, RAS, and NF1 mutations are described as the major melanoma drivers, but approximately 20% of patients lack these mutations and are included in the triple wild-type (tripleWT) classification. Recent advances in targeted therapy directed at driver mutations along with immunotherapy have only partially improved patients' overall survival, and consequently, melanoma remains deadly when in advanced stages. Fucose-containing sulfated polysaccharides (FCSP) are potential candidates to treat melanoma; therefore, we investigated Fucan A, a FCSP from Spatoglossum schröederi brown seaweed, in vitro in human melanoma cell lines presenting different mutations. Up to 72 h Fucan A treatment was not cytotoxic either to normal melanocytes or melanoma cell lines. Interestingly, it was able to impair the tripleWT CHL-1 cell proliferation (57%), comparable to the chemotherapeutic cytotoxic drug cisplatin results, with the advantage of not causing cytotoxicity. Fucan A increased CHL-1 doubling time, an effect attributed to cell cycle arrest. Vascular mimicry, a close related angiogenesis process, was also impaired (73%). Fucan A mode of action could be related to gene expression modulation, in special β-catenin downregulation, a molecule with protagonist roles in important signaling pathways. Taken together, results indicate that Fucan A is a potential anticancer molecule and, therefore, deserves further investigation.