Pro-apoptotic properties of (1,3)(1,4)-β-d-glucan from Avena sativa on human melanoma HTB-140 cells in vitro

In this study, the growth-inhibitory effect of polysaccharide (1,3)(1,4)-β-d-glucan from oat, Avena sativa L. grains was explored on the human skin melanoma HTB-140 cells in vitro. The oat β-d-glucan (OBG) exerted cytotoxic action on HTB-140 cells. After 24 h of incubation, LD50 (concentration at which 50% of the cells were found dead) was obtained of 194.6 ± 9.8 μg/mL. The oat β-d-glucan caused a concentration-dependent increase of caspase-3/-7 activation and appearance of phosphatidylserine on the external surface of cellular membranes where it was bound to annexin V-FITC, demonstrating the induction of apoptosis. Intracellular ATP level decreased along with the mitochondrial potential, which suggested a mitochondrial pathway of apoptosis. A cell cycle analysis showed increase in the number of apoptotic cells, increase in the number of cells in G1 phase and decrease in the number of cells in G2/M. Although the detailed mechanism for the anti-tumor activity of the oat β-d-glucan still needs further investigation, this study provides preliminary insights into this direction along with perspectives of developing it as an anti-tumor agent.

Graphical abstract

Introduction

β-d-Glucan is a specific fiber-type complex polysaccharide which can be derived from the cell wall of baker’s yeast, and many medicinal mushrooms or bacteria, as well as widely consumed cereals, such as oats and barley [1]. Immunomodulation by β-d-glucan was confirmed both in vitro and