Design,Synthesis And Evaluation Of E-Selectin Peptide Ligand-PEG-HSA Conjugates

Most cancer chemotherapy drugs lack targeting.So,this study uses human serum albumin(HSA)as a functional carrier to target tumor.It has good biocompatibility and can be actively targeted to certain proteins(gp60 and SPARC)in the tumor site.At the same time,E-selectin peptide ligands can also actively identify tumor sites.So on the surface of HSA,E-selectin peptide ligands and poly Ethylene glycol(PEG)were conjugated further to improve tumor targeting.Thus,ligand-receptor binding is used to inhibit the adhesion and migration of tumor cells on the surface of endothelial cells.In this study,E-selectin peptide ligand and PEG were coupled to the surface of HSA via different linkers.One of the them is a triazole bridge(SXZ-A150-189-1),and the other was a thioether bridge(SXZ-A215-54-1).The two target conjugates were successfully prepared via solid-phase synthesis,amide condensation,redox,and click reactions.Through RP-HPLC,NMR,MALDI-TOF etc,the purity and structure of important intermediates and target conjugates were analyzed and identified.The results showed that the purity meet the requirements and the structures were correct.The SDS-PAGE results of the final target conjugates preliminarily indicated that the HSA surface was successfully connected with 3-4 biconjugates of PEG and E-selectin peptide ligand.Then the hydration radius and Zeta potential of the target products were tested by DLS.The results showed that the HSA had a nanoparticle size of 4 nm and a Zeta potential of-27.3 mV.The nanoparticle size of SXZ-A150-189-1 and SXZ-A215-54-1 were 68.10 nm and 9.33 nm,respectively,and the Zeta potentials were-8.31 mV and-27.9 mV,respectively.The nanoparticle sizes become larger and maintain the original negative potential of HSA.Finally,HUVEC and HL-60 cells were used to test the anti-adhesion activity of the target products.The results showed that SXZ-A215-54-1 can inhibit the adhesion between HL-60 cells and activated vascular endothelial cells HUVEC,so it has the potential to prevent tumor metastasis.While under the same conditions,SXZ-A150-189-1 did not show obvious inhibition of the adhesion of HL-60 with HUVVEC.On the one hand may be related to differences in nanoparticle morphology,size,conformation,etc.On the other hand,due to the SXZ-A150-189-1 is directly coupled to the terminal amino group on the heptapeptide,affecting the activity of the target product.Simultaneously,DLS results show that the nanoparticle size of SXZ-A150-189-1 is much larger than that of SXZ-A215-54-1.It can be inferred that different linkers have a significant influence on the degree of aggregation,surface charge and biological activity of the nanoparticles.