Mechanism regulating the inhibition of lung cancer A549 cell proliferation and structural analysis of the polysaccharide Lycium barbarum

Abstract

The water-soluble polysaccharide LBP-1 was isolated and characterized from Lycium barbarum L. LBP-1 was mainly composed of arabinose, galactose, glucose, xylose, mannose at a molar ratio of 37.53: 28.08: 14.72: 7.83: 4.50, respectively. Based on nuclear magnetic resonance (NMR) and methylation analysis, the backbone of LBP-1 was speculated in the α-L-Ara(1→[5-α-L-Ara(1 → 3)-β-D-Galp-(1→]n→4)-α-D-Galp-(1[→5-α-L-Ara (1]n [→6)-β-D-Galp-(1 → 4)-β-D-Galp-(1→]n, and the side chains of LBP-1 were in the α-L-Ara(1 → 3)-β-D-Galp-(1 → 6 position. These results showed that LBP-1 inhibited the growth of cancer A549 cells through cell cycle arrest and apoptosis, with an IC50 value of 42.5 μg/mL. In addition, LBP-1 altered the expression of Cyclin D1, Cyclin D3, and CDK 2, thus blocking the cell cycle in G0/G1 phase, reducing cell migration, and regulating the PI3K/Akt/mTOR signaling pathway to induce apoptosis.