Antioxidant stress and anticancer activity of peptide‑chelated selenium in vitro

The association between selenium and peptide in gastric cancer is an important research topic. The present study reported the facile synthesis of anticancer bioactive peptide (ACBP)‑functionalized selenium (ACBP‑S‑Se) particles with enhanced anticancer activities and a detailed mechanistic evaluation of their ability to regulate oxidative stress in vitro. Structural and chemical characterizations were revealed by ultraviolet absorption, Fourier transform infrared, X‑ray photoelectron, nuclear magnetic resonance carbon and hydrogen, energy dispersive X‑ray spectroscopy and inductively coupled plasma mass spectrometry, as well as scanning electron microscopy. Sulfhydrylation modifications of ACBP were achieved with S‑acetylmercaptosuccinic anhydride via chemical absorption. After the polypeptide was modified by sulfhydrylation, the ACBP chain was linked to sulfhydryl groups by amide bonds to form the ACBP‑chelated selenium complex. Two gastric cancer cell lines (MKN‑45 and MKN‑74 cells) demonstrated high susceptibility to ACBP‑S‑Se particles and displayed significantly decreased proliferation ability following treatment. The results suggested that the bioactive peptide‑chelated selenium particles effectively inhibited the proliferation of MKN‑45 and MKN‑74 cells in vitro. The genes encoding CDK inhibitor 1A (CDKN1A), cyclin B1, thioredoxin (TXN) and mitogen‑activated protein kinase kinase kinase 5 are associated with regulation of oxidative stress, while CDKN1A and TXN protect cells by decreasing oxidative stress and promoting cell growth arrest. Therefore, ACBP‑S‑Se may be an ideal chemotherapeutic candidate for human cancer, especially gastric cancer.