A Atractylodes lancea polysaccharide inhibits metastasis of human osteosarcoma U-2 OS cells by blocking sialyl Lewis X (sLex )/E-selectin binding.

In this study, a new water and alkaline-soluble polysaccharide (ALP), with an average molecular weight of 6.63 × 10⁴  Da, was successfully purified from the rhizomes of Atractylodes lancea. GC analysis demonstrated that ALP was a kind of glucan. The effect of the ALP on the interaction between E-selectin and sialyl Lewis X (sLe^x ) was examined in human osteosarcoma U-2 OS cells. It was obvious that the expression of sLe^x antigen on the surface of U-2 OS cells was visible under fluorescence microscopy. The addition of ALP (0.5, 1 and 2 mg/mL) resulted in a marked inhibition on the adhesion, migration and invasion of U-2 OS cells to human umbilical vein endothelial cells (HUVECs), which was achieved by the decreased sLe^x expression on U-2 OS cells. Additionally, the induction of apoptosis can be observed in U-2 OS cells following ALP treatment using TUNEL staining and Annexin V-FITC/PI double-staining analysis on flow cytometry. In conclusion, these results indicated that ALP exerted anti-metastatic activity towards osteosarcoma cells via inhibition of sLe^x /E-selectin binding, which suggested that ALP could be a potent agent for human osteosarcoma intervention.