Meridianin C is a marine natural product with anticancer activity. Meridianin C has significant inhibitory effects on four different human tongue cancer cells (YD-8, YD-10B, YD-38 and HSC-3). Meridianin C most strongly reduced the growth of YD-10B cells, the most aggressive and tumorigenic of the cell lines tested. Meridianin C also induced significant accumulation of large vesicles in YD-10B cells, validating its function through macrophagocytosis. Meridianin C reduces cellular levels of Dickkopf-related protein-3 (DKK-3), a known negative regulator of macrophagy. Meridianin C affects macrophagocytosis by downregulating DKK-3, thereby affecting cell proliferation[1].