SGP-2, an acidic polysaccharide from Sarcandra glabra, inhibits proliferation and migration of human osteosarcoma cells

An acidic polysaccharide (SGP-2), with a molecular weight of 1880 kDa, was purified from the defatted whole-plant of Sarcandra glabra (Thunb.) Nakai. SGP-2 is mainly composed of glucose, galactose, mannose, arabinose and galacturonic acid in a molar ratio of 12.19 : 8.68 : 6.03 : 1.00 : 15.24. The primary structure analysis reveals that SGP-2 consists of 1,4-linked alpha-D-galacturonic acid, methyl-esterified 1,4-linked a-D-galacturonic acid, 1,5-linked alpha-I-arabinose, 1,4-linked alpha-D-mannose, 1,6-linked beta-D-glucose and 1,3-linked beta-D-galactose with branch chains of 1,4,6-linked beta-D-glucose, 1,3,6-linked alpha-D-mannose and 1,4,6-linked alpha-D-galactose. The results of a cell viability assay and colony formation assay indicate that SGP-2 has a potent anti-proliferation activity on human osteosarcoma MG-63 cells. SGP-2 increases the proportion of apoptotic cells and activates caspase-3. In addition, the anti-proliferation effect induced by SGP-2 is blocked by the pan-caspase inhibitor. Moreover, SGP-2 inhibits the migratory capacity of MG-63 cells accompanied with the inhibition of receptor for advanced glycation end-products (RAGE) and nuclear factor-kappa B (NF-kappa B). Taken together, these results suggest that SGP-2 has anti-cancer potential in the treatment of human osteosarcoma.