Amaranth lunasin-like peptide internalizes into the cell nucleus and inhibits chemical carcinogen-induced transformation of NIH-3T3 cells

Because an unbalanced diet is an important risk factor for several illnesses, interest has increased in finding novel health-promoting foods. Amaranth produces seeds that not only have substantial nutritional properties but that also contain phytochemical compounds as rutin and nicotiflorin and peptides with antihypertensive and anticarcinogenic activities. We report that a cancer-preventive peptide in amaranth has activities similar to those of soybean lunasin. The amaranth lunasin-like peptide, however, requires less time than the soybean lunasin to internalize into the nucleus of NIH-3T3 cells, and inhibits histone acetylation (H3 and H4 in a 70 and 77%, respectively). The amaranth lunasin-like peptide inhibited the transformation of NIH-3T3 cells to cancerous foci. The open reading frame (ORF) of amaranth lunasin corresponds to a bifunctional inhibitor/lipid-transfer protein (LTP). LTPs are a family of proteins that in plants are implicated in different functions, albeit all linked to developmental processes and biotic and abiotic stress resistance. Our results open new intriguing questions about the function of lunasin in plants and support that amaranth is a food alternative containing natural peptides with health-promoting benefits.

Research highlights▶ The cancer-preventive peptide in amaranth has in vitro activities similar to those of soybean lunasin. ▶ The amaranth lunasin-like peptide requires less time than the soybean lunasin to internalize into the nucleus of NIH-3T3 cells. ▶ The open reading frame (ORF) of amaranth lunasin, corresponds to a bifunctional inhibitor/lipid-transfer protein (LTP). ▶ Our results open new intriguing questions about the function of lunasin in plants.