Preparation of Lycium barbarum active glycopeptide and investigate its apoptotic effects on melanoma

Abstract

Abstract Previous studies have shown that the L. barbarum fruit polysaccharides could inhibit the growth of cancer cells, but the active ingredient and mechanism of melanoma inhibition are unknown. The preparation of L. barbarum active glycopeptide (LBAG) and its composition was studied to investigate its mechanisms of action on melanoma. LBAG from L. barbarum was extracted and isolated using aqueous-alcoholic precipitation and identified by ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry. Then，how LBAG affected the apoptosis and cell cycle of B16 cells was explored by colony formation assay, cell scratch test, flow cytometry, and Western blot. LBAG had a molecular weight of 10-15 kDa and contained Man, Rha, GlcA, Glc, Gal, and Ara as well as 18 amino acids. Treatment with LBAG significantly decreased B16 cell proliferation and induced cycle arrest at phase G0/G1, which was accompanied by the accumulation of reactive oxygen species. Western blot revealed that LBAG induced the apoptosis and cycle arrest of B6 cells by decreasing the phosphorylation of p38-MAPK and Akt, and the effects were inhibited by N-acetyl-L-cysteine. In mouse xenografts, LBAG inhibited tumor growth via p38-MAPK and AKT signaling. LBAG induces apoptosis in B16 cells through ROS-mediated activation of p38-MAPK and Akt signaling pathways.