Anticancer activity of a novel glycoprotein from Camellia oleifera Abel seeds against hepatic carcinoma in vitro and in vivo

Glycoproteins are naturally occurring biological macromolecule that possess known pharmacological properties. This study investigated the anticancer potential of a new glycoprotein, COG2a with the weight-average molecular weight of 25.9 kDa, isolated from Camellia oleifera Abel seeds by multiple column chromatography and the mechanism of anticancer action. MTT assay showed that the maximum inhibition rate of COG2a on HepG2 cells was 92.1%. Electron microscopic and fluorescence microscopy observation indicated that the HepG2 cells treated with COG2a exhibited typical apoptotic morphological character. Flow cytometry manifested that COG2a induced the cell cycle arrest at the G2 phases and decreased in mitochondrial membrane potential on the HepG2 cells. Western blotting exhibited that COG2a increased the expressions of the pro-apoptotic protein caspase-3 and Bax and decreased the expression of the anti-apoptotic proteins Bcl-2. Additionally, COG2a exerted an obvious anticancer effect on tumor-bearing mice and the maximum tumor inhibition rate is 72.77%. It also can promote the mouse thymus and pancreas index, the number of T lymphocytes cell subset and interferon-gamma to increase. These results indicate that COG2a exhibits in vitro and in vivo anticancer activities that associate with its immunopotentiation properties and may serve as a potential anticancer agent.