The Construction Of Size-controllable Nano-drug Delivery System And Study On Their Anti-hepatocellular Carcinoma Efficacy

In present paper,biodegradable dendrimer poly-L-lysine(DGL)was selected as the core skeleton of nanoparticles.The glycyrrhetinic acid(GA)and 1,2-dicarboxyliccyclohexene anhydride(DCA)were acted as the targeting ligand and the positively charged blocker,respectively,and were covalently bound to DGL by the amidation reaction.The anticancer drug DOX was uploaded by electrostatic adsorption.The resultant intermediate product(DGL-GA-DCA-DOX)was coated with hyaluronic acid(HA)to obtain the end-product DGL-GA-DCA-DOX-HA nanoparticles with an ideal size.It was expected that on the basis of EPR effect,HA shell was hydrolyzed by hyaluronidase that was overexpressed in the tumor microenvironment,in turn,the nanoparticle size can be shrunk at targeting site,so that the nanoparticles can successfully penetrate into the central part of the solid tumor.Furthermore,DOX was precisely transported to hepatocellular carcinoma cells and released into the cytoplasm under synergistic action of cell internalization mediated by GA and lysosomal escape triggered by DCA.The integration of above multiple functions into a single formulation has greatly exerted the excellent anti-tumor effect of nanoparticles.The physico-chemical properties of DGL-GA-DCA-DOX-HA nanoparticles and their anti-tumor efficacy were studied.The morphologies,size distributions and chemical structures of nanoparticles were characterized by means of transmission electron microscope(TEM),dynamic light scattering(DLS)and fourier transform infrared spectrometer(FTIR).According to the results of TEM and DLS,the DGL-GADCA-DOX-HA could be degraded with a size shrink from 182.5 nm to 47.7 nm by hyaluronidase(HAase)which was highly expressed at the tumor microenvironment.The loading amount of DOX reached 148.3 mg/g for end product DGL-GA-DCADOX-HA nanoparticles.The drug release showed an anticipative behavior with slow pattern in the media of neutral pH or absence of HAase but relatively fast mode in pH 5.0 medium containing HAase.The studies of the in vitro HepG2 cells in a monolayer culture demonstrated that introduction of GA to nanoparticles significantly enhanced affinity and cytotoxicity to hepatocellular carcinoma HepG2 cells.In the study of multicellular tumor spheroids,it was fully proved that the DGL-GA-DCA-DOX nanoparticles unwrapped by hyaluronic acid(HA)and the DGL-GA-DCA-DOX-HA nanoparticles degraded by HAase consistently showed the strongest tumor permeability.The imaging in vivo and ex vivo exhibited that DGL-GA-DCA-DOX-HA nanoparticles could preferentially accumulate in the tumor site.Correspondingly,the DGL-GADCA-DOX-HA displayed the excellent antitumor efficiency with a tumor inhibition rate of 71.6% in H22 tumor-bearing mice.In short,these results had proved that the functionally synergized DGL-GA-DCA-DOX-HA nanoparticles could achieve both modulation of the particle size for heightening targeting and penetration and GAmediated endocytosis,so as to improve the therapeutic effect.