The Marine-Derived Oligosaccharide Sulfate MS80, a Novel Transforming Growth Factor β1 Inhibitor, Reverses Epithelial Mesenchymal Transition Induced by Transforming Growth Factor-β1 and Suppresses Tumor Metastasis.

Metastasis accounts for the majority of cancer-related deaths. Transforming growth factor β (TGF-β) is believed to promote late-stage cancer progression and metastasis by inducing epithelial-mesenchymal transition (EMT). We previously reported that MS80, a novel oligosaccharide sulfate, inhibits TGF-β1-induced pulmonary fibrosis by binding TGF-β1. In our study MS80 effectively inhibited TGF-β/Smad signaling in lung cancer cells, breast cancer cells, and model cell lines. In addition, MS80 inhibited TGF-β1-induced EMT, motility, and invasion in vitro. Moreover, MS80 significantly inhibited lung metastasis in orthotopic 4T1 xenografts. Notably, the MS80 treatment significantly increased the infiltration of CD8(+) T cells and decreased the infiltration of regulatory T cells in primary tumors and spleens in mice bearing 4T1 xenografts. Therefore, MS80 is a novel and promising candidate for treating metastatic malignancies by targeting TGF-β1-induced EMT and mediating immunosuppression.