Algal sulfated carrageenan inhibits proliferation of MDA-MB-231 cells via apoptosis regulatory genes

Marine algae are prolific sources of sulfated polysaccharides, which may explain the low incidence of certain cancers in countries that traditionally consume marine food. Breast cancer is one of the most common types of non‑skin cancer in females. In this study, extracted sulfated carrageenan (ESC), predominantly consisting of ι‑carrageenan extracted from the red alga Laurencia papillosa, was characterized using Fourier transform infrared spectrometry. The biological effects of the identified extract were investigated and its potential cytotoxic activity was tested against the MDA‑MB‑231 cancer cell line. The biological biometer of the inhibitory concentration of the polysaccharide‑treated MDA‑MB‑231 cells was determined as 50 µM. Treatment with 50 µM ESC inhibited cell proliferation and promptly induced cell death through nuclear condensation and DNA fragmentation. Characterization of polysaccharide‑treated MDA‑MB‑231 cell death revealed that induction of apoptosis occurred via the activation of the extrinsic apoptotic caspase‑8 gene. The apoptotic signaling pathway was regulated through caspase‑3, caspase‑9, p53, Bax and Bcl‑2 genes. These findings suggest that ESC may serve as a potential therapeutic agent to target breast cancer via prompting apoptosis.