Functional exploration of lunasin peptide in transgenic maize (Zea mays L.) and its role in controlling mitophagy in MDA-MB-231 cells

Lunasin, a novel bioactive peptide initially found in soybean, exhibits multiple biological functions. Here, we overexpressed lunasin in maize to generated the transgenic maize with high lunasin content for application in functional food. A maize variety YF464 was screened and used as receptor material (WT), and the identification of lunasin peptide in maize was demonstrated through Western blot and ultrahigh pressure liquid chromatography–electrospray ionization with tandem mass spectrometry (UPLC-ESI-MS/MS). Thirteen overexpression (OE) lines were obtained, then OE1 (182.34 ± 13.62 μg g−1) and OE2 (294.51 ± 34.25 μg g−1) were selected for further study based on high expression of lunasin. Lunasin extract from maize (LEM) presented significantly higher antioxidant, anti-inflammatory, and anti-cancer activity in OE lines than that from WT. Furthermore, LEM from OE1 and OE2 showed superior anti-proliferation function on human breast cancer cells MDA-MB-231 than that from WT. Combination analysis with matched proteins from transcriptome and proteome after lunasin exposure showed that genes and proteins associated with mitophagy was highly activated in MDA-MB-231 cells, indicated lunasin may act an important role in promoting mitophagy, inducing cell death. Therefore, lunasin overexpressing maize has a great potential as a functional food in the diets of patients with cancer, together with an alternative for dietary nutrition and health care in the future. More importantly, it will provide the scientific data for further exploration on its anti-cancer function.