The Functional And Mechanism Study Of Food Derived Peptides Which Inhibit Pancreatic Cancer Cell Metastasis

Pancreatic cancer is a digestive system malignant carcinoma which is difficμ Lt to be diagnosed and cured,five year mortality rate of patients is more than 95%.With the extremely poor prognosis,the pancreatic cancer has been regarded as one of the most challenging malignant tμMor in general surgery.The majority of patients are diagnosed with metastatic disease,which is also the leading cause of pancreatic cancer death.The aim of this study was to screen the food-derived(in our study is bovine hemoglobin and soybeans)functional peptides with anti-metastatic effect via virtual enzymolysis by computer.We used the computer and software to simμLate the process of enzymolysis by pepsin and trypsin,so that we gained a variety of peptides.Then we sorted them within the energy consμMption for virtually docking with Hsp90 and finalized six potential candidates.We identified the tetrapeptide Asn-Phe-Gly-Lye(NFGK)as the most effective one among the six against the migration of pancreatic cancer cell MIAPaCa-2 via the wound-healing assay.Then we confirmed its inhibition effect to cell migration as well as to cell invasion by transwell migration/invasion assay.Meanwhile,we proved that NFGK does not exhibit cytotoxicity on MIAPaCa-2 cells in cell proliferation assay.Fluorescence confocal imaging data revealed that NFGK targeted the cell membrane of MIAPaCa-2.MolecμLar docking data displayed that NFGK bond to the N-terminus ATP-binding pocket of secreted heat shock protein 90α(Hsp90α).Western blotting resμLts further proved that NFGK inhibited secreted Hsp90α and downstream matrix metalloproteinase-9(MMP-9)level dose dependently,while it did not inhibit intracellμLar Hsp90 and cyclin-dependent-kinase 4(CDK4).All above resμLts demonstrated that bovine hemoglobin derived peptide NFGK inhibited pancreatic cancer cell metastasis by targeting secreted Hsp90α and its downstream MMP-9.Similarly,we screened for the most potentially effective soybean peptide and identified a pentapeptide Tyr-Pro-Thr-Ser-Lys(YPTSK)which has anti-metastasis effect and no cytotoxicity.Unlike the NFGK,YPTSK coμ Ld get through the cell membrane and exist intracellμLarly shown in the fluorescence confocal assay.In addition,YPTSK did not inhibit the ATPase activity of Hsp90 as well as the protein expression level,but it suppressed the protein expression level of AKT and MMPs.Consistently,RT-PCR assay revealed that the mRNA level of some MMP protein family members have been inhibited by YPTSK.Our study has provided new strategy for pancreatic cancer therapy as well as an approach to recycle the discarded product in agricμ Lture and animal husbandry.