The Cytotoxic and Apoptotic Effects of the Brown Algae Colpomenia sinuosa are Mediated by the Generation of Reactive Oxygen Species

Brown algae are a novel resource of biogenic molecules, however few studies have been conducted in the Mediterranean to assess the cytotoxic mechanisms of algal-derived compounds. This study focuses on the antineoplastic activity of extracts from non-investigated algae of the Lebanese coast, . Extracts' antineoplastic activities were evaluated by MTT and trypan blue on different tumorigenic cells. Results indicated that the most potent extract was obtained by soxhlet using dichloromethane:methanol solvent (DM soxhlet) against HCT-116. Wound healing assay confirmed that this extract decreased the migration potential of HCT-116 cells with minimal effects on non-tumorigenic cells. It also induced an increase in the subG1 population as determined by flow cytometry. Western blot analysis demonstrated that apoptosis in treated HCT-116 cells was induced via upregulation of p21 protein and downregulation of the anti-apoptotic Bcl 2, which led to caspases activation. The latter, catalyzes the degradation of PARP-1, and thus suppresses cancer proliferation. Morphological alterations, further confirmed apoptosis. A strong pro-oxidant activity evidenced by the enhanced generation of reactive oxygen species (ROS) was observed in HCT-116 treated cells. Interestingly, a strong antioxidant effectively blocked effect induced by the extract. These results indicate that is a source of bioactive compounds possessing pro-apoptotic and anti-migratory efficacy.