Different molecular weight fucogalactans from Macrocybe titans mushroom promote distinct effect on breast cancer cell death

There is an incessant search for new therapies against cancer, able to unite effectiveness with specificity, leading to higher survival rates and lower deleterious effects. Herein, two fucogalactans (F-1 and F-2), isolated from Macrocybe titans, showed a (1 → 6)-linked α-D-Galp main chain partially substituted at O-2 by non-reducing end units of α-L-Fucp, with different M_w, being F-2 > 20 times higher than F-1. Both fucogalactans induced cell cycle arrest of MDA-MB-231 cells in G1 phase after 120 h of treatment. However, only F2 resulted in increased apoptosis and necrosis. For the MCF-7 cell line, no changes in the cell cycle and cell death were observed at 120 h. The non-tumoral cell line (VERO) was not affected. The results confirmed that polysaccharides with different M_w may have distinct effects and therefore this is an important feature to be considered on investigating anti-cancer treatments.