iCellular uptake of [1-9-NαC]-linusorb B2 and [1-9-NαC]-linusorb B3 isolated from flaxseed, and their antitumor activities in human gastric SGC-7901 cellse

The aim of this study was to investigate the cellular uptake and antitumor activity of 2 different structural flaxseed orbitides ([1-9-N alpha C]-linusorb B2 containing methionine residue and [1-9-N alpha C]-linusorb B3 containing isoleucine residue) in SGC-7901 cells as well as its underlying molecule mechanism. Results showed that the absorption efficiency of [1-9-N alpha C]-linusorb B3 was higher than that of [1-9-N alpha C]-linusorb B2. Besides, through the evaluation of mitochondrial membrane potential (A phi m), cytochrome c (Cyt C) release, caspase, death receptor activation and cleavage of PARP, we found that [1-9-N alpha C]-linusorb B3 exhibited more obvious apoptosis induction on SGC-7901 cells than [1-9-N alpha C]-linusorb B2. Interestingly, [1-9-N alpha C]-linusorb B3-induced cell apoptosis might involve a mitochondrial- and death receptor-mediated intrinsic and extrinsic pathway; however, [1-9-N alpha C]-linusorb B2 induced cell apoptosis by the activation of Fas, FasL, caspase 8 as well as caspase 3 instead of Box, Cyt C, tBid and caspase 9, suggesting that extrinsic pathway might be involved in the apoptotic process.