The phytochemical vitexin and syringic acid derived from foxtail fillet bran inhibit breast cancer cells proliferation via GRP78/SREBP-1/SCD1 signaling axis

[Display omitted] •BPIS specifically inhibited breast cancer via blocking the conversion of SFA to MUFA.•VT and SA were the anti-breast cancer active ingredients of BPIS.•GRP78 was the target of VT and SA and mediated the conversion of SFA to MUFA. Breast cancer is the most frequently diagnosed malignant tumor in women. Foxtail millet is an important cereal food and exhibits a wide range of nutrition. We previously extracted total polyphenols composed of 12 compounds from foxtail millet bran (named BPIS). In this study, we find that BPIS inhibits the proliferation of breast cancer cells by restraining the cellular membrane synthesis via suppressing the conversion of saturated fatty acids (SFA) to monounsaturated fatty acids (MUFA). Mechanically, BPIS decreases the glucose regulated protein 78 (GRP78) level, which further inhibits the expression of SREBP-1 and downstream-target SCD1. Combining molecular docking, MTT screening and in vivo model, we ultimately identify that vitexin and syringic acid are the main active ingredients. Our data showed that the combination of vitexin and syringic acid suppress the proliferation of breast cancer cells, which support further study of BPIS as a new dietary assistant strategy to improve breast cancer.