Transformable Peptide Nanostructures Modulate Self-assembly Of Vimentin In Vivo For Inhibiting Metastasis Of Tumor

Tumor metastasis refers to the phenomenon that tumor cells spread from the primary tumor and eventually grow in the distance,usually with a poor prognosis.The deaths resulted from tumor metastasis accounted for the vast majority of tumor-related deaths.Studies have shown that all malignant tumor cells of epithelial origin undergo EMT process during metastasis,and many key proteins related to tumor metastasis are abnormally expressed to promote tumor cell metastasis.This paper draws on the strategy of receptor regulation and designs a new type of self-assembled peptide nanomaterials,which can inhibit tumor metastasis by regulating vimentin related to tumor metastasis.In this paper,a novel transformable peptide nanomaterial BFV was synthesized by solid-phase synthesis,and its chemical structure was confirmed by MALDI-TOF-MS and~1H-NMR.The self-assembled transformable peptide nanomaterial BFV was designed and synthesized in this paper combines the stability,excellent biocompatibility and functionality of the self-assembled body and the size advantages of the nanomaterial.The BFV material is composed of bis-pyrene molecules(BP),KLVFF peptide unit and VNTANST targeting peptide unit.Among them,BP has strong hydrophobicity and?-?stacking effect,which provides a driving force for the formation of nanoparticles by self-assembly,and BP shows excellent AIE effect,which can be used for fluorescent tracking of materials;KLVFF peptide unit are derived from A?42 amyloid,which can assist nanoparticles transform into nanofibers through the formation of intermolecular hydrogen bonds;VNTANST targeting peptide unit,which can specifically bind to vimentin in tumor cells.In animals,BFV nanoparticles are enriched in the tumor area by the EPR effect.After entering the tumor cells,the nanoparticles actively bind to vimentin.At this time,the nanoparticles transformed into nanofibers in situ,forming a physical barrier on the surface of vimentin and destroying dynamic assembly balance of vimentin.,thereby inhibiting the movement ability of tumor cells,and finally achieving the purpose of inhibiting tumor metastasis.Through FL,UV-Vis,CD,FT-IR and TEM characterization,the self-assembly morphology of the peptide nanomaterial BFV and the morphology transformation after interacting with ligand-receptor were explored.BFV self-assembles in aqueous environment to form nanoparticles with a diameter of68.0±15.0 nm.After interacting with vimentin,the nanoparticles transformed into nanofibers which have?-sheet structure and have a maximum diameter of?=23.2±9.5 nm.In the cell experiment,the biological functionalities were verified by the wound healing assays and the transwell migration/invasion assays.For breast cancer cell lines MDA-MB-231 and MCF-7,the wound healing inhibition rate by BFV was 32.7%and 56.2%,migration inhibition rates were 91.4%and 83.4%,and invasion inhibition rates were 97.6%and 85.2%,respectively.The results demonstrate the ability of BFV to inhibit tumor cell metastasis and invasion from both lateral and vertical directions.CLSM imaging found that the fluorescent signal of BFV overlaps with that of vimentin.CLSM imaging found that the fluorescent signal of BFV overlaps with that of vimentin and BFV can enrich vimentin around the nucleus,which proved that BFV can specifically target vimentin in tumor cells and has excellent vimentin regulation ability.In in vivo experiments,through the in vivo fluorescence test of small animals and the drug metabolism experiments of various organs,it was found that the fluorescence signal of BFV was strong in the tumor area,and there was still a significant fluorescence signal after 72 h,which proved that BFV can be enriched in the tumor area and stay for a long time.In the mice model of tumor metastasis,by comparing the number of lung nodules,lung pathological sections images and the tumor volume of mice,it was found that the number of lung metastases was significantly reduced.Compared to the blank group that the tumor volume increased by 7,the tumor volume only increased by 3.4 in 19 days in the mice treated with BFV.It proved that BFV can effectively inhibit tumor metastasis.By observing the pathological slices of various organs and counting the weight changes of mice,it was found that the heart,liver,spleen and kidney tissues of the mice treated with BFV did not have lesions and the mice body weight was stable,proving that BFV has good biological safety.