Immunomodulatory effects of flavonoids: An experimental study on natural-killer-cell-mediated cytotoxicity against lung cancer and cytotoxic granule secretion profile

Abstract

Background: A new approach involving immune-cell-mediated cancer therapy has been adopted extensively for the sake of lung cancer treatments by utilizing natural killer (NK) cells. NK cell activity can be enhanced with certain agents, and among them are flavonoids. Thus, this study was conducted to investigate the immunomodulatory roles of apigenin, luteolin and quercetin on NK cell activity against lung cancer cells and on the secretions of perforin and granulysin profile. Methods: The NK-92 cells were grown in complete α-Minimum Essential Medium (MEM). NCI-H460 lung cancer cells were cultured in Roswell Park Memorial Institute 1640 media. NK cell activity against lung cancer cells were done using MTT(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The secretions of perforin and granulysin profiles were then analysed using enzyme-linked immunosorbent assay. Results: Apigenin, luteolin and quercetin significantly increased the NK-cell-mediated cytotoxic activity against lung cancer cells at concentrations 12.5 µg/ml and 25µg/ml ( P < 0.001). The secretion levels of perforin and granulysin from NK cells were also significantly enhanced with apigenin and luteolin treatment but not with quercetin. Conclusions: All three flavonoid compounds possessed some significant immunomodulatory actions on NK cell cytotoxic activity and granule secretion profiles towards lung cancer therapy.