Porcupine quills keratin peptides induces G0/G1 cell cycle arrest and apoptosis via p53/p21 pathway and caspase cascade reaction in MCF‐7 breast cancer cells

BACKGROUND Porcupine quills, a by‐product of porcupine pork, are rich in keratin, which is an excellent source of bioactive peptides. The objective of this study was to investigate the underlying mechanism of anti‐proliferation effect of porcupine quills keratin peptides (PQKPs) on MCF‐7 cells. RESULTS Results showed that PQKPs induced MCF‐7 cells apoptosis by significantly decreasing the secretion level of anti‐apoptosis protein Bcl‐2 and increasing the secretion levels of pro‐apoptosis proteins Bax, cytochrome c, caspase 9, caspase 3 and PARP. PQKPs also arrested the cell cycle at G0/G1 phase via remarkably reducing the protein levels of CDK4 and enhancing the protein levels of p53 and p21. High‐performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) analysis identified nine peptides with molecular weights less than 1000 Da in PQKPs. Molecular docking results showed that TPGPPT and KGPAC identified from PQKPs could bind with p53 mutant and Bcl‐2 protein by conventional hydrogen bonds, carbon hydrogen bonds and van der Waals force. Furthermore, the anti‐proliferation impact of synthesized peptides (TPGPPT and KGPAC) was shown in MCF‐7 cells. CONCLUSION These findings indicated that PQKPs suppressed the proliferation of MCF‐7 breast cancer cells by triggering apoptosis and G0/G1 cell cycle arrest. Moreover, the outcome of this study will bring fresh insights into the production and application of animal byproducts. © 2023 Society of Chemical Industry.