Modulation of cancer cell proliferation by unusually produced β(1-6) linked Mannan-oligosaccharides and β(1-6) linked Galactooligosaccharides using β–galactosidase from Aspergillus oryzae

Abstract

This study introduced an alternative way to produce NDOs, utilizing the recently reported unusual β-galactosynthase-β-mannosynthase dual activity of this enzyme, using free monosaccharide substrates. The enzyme successfully converted galactose and mannose monomer sugars efficiently to NDOs. Glycoblotting and MALDI-TOFMS analyses confirmed that the enzyme produced a maximum of 46.37% galacto-oligosaccharides (36.88% galactobiose, 8.52 % galactotriose, and 0.9746 % galactotetraose) from galactose monosaccharides and 32.62 % mannan-oligosaccharides (30.95 % mannobiose and 1.68 % mannotriose) from mannose monosaccharides. Both MOS and GOS modulated cell growth of different human cancer cell lines, with apparent antiproliferative effect on prostate adenocarcinoma (PC-3) cells and mitogenic effects on A549, HepG2, and HT-29. Mitochondrial membrane potential and careful morphological evaluation of PC-3 cells treated with GOS and MOS suggested that MOS treated cells showed possible inhibition of cellular adhesion that might have caused apoptosis to advance. The high-yielding NDOs synthase character of this cheaply available βgalactosidase makes this new strategy a good potential alternative in producing prebiotic NDOs. Keywords:Non-digestible oligosaccharides Galacto-oligosaccharides Mannan-oligosaccharides Asprgillus oryzae β-galactosidase Glycoblotting