Tumor Microenvironment Responsive Delivery System For SiRNA And Near-infrared Zone II Autophagy Regulator Synergistic Therap

According to the data of the global cancer burden in 2020 released by the International Agency for Research on Cancer（IARC）of the World Health Organization,there were 9.96 million cancer deaths worldwide in2020,and the number of new cancer cases in the world is expected to reach nearly 30 million in 2040.Cancer has become a century problem plaguing human health.RNA interference is a phenomenon of gene silencing mediated by exogenous or endogenous Dsrnas（such as si RNA and micro RNA,mi RNA）,which is one of the most effective and advanced gene therapy methods at present.As a powerful tool for gene expression inhibition,RNAi has shown excellent therapeutic potential in preclinical trials.Based on the previous discovery of NIR-Ⅱautophagy regulator HD,this paper synthesized and constructed p H responsive nanoparticles for the co-delivery of autophagy regulator HD and KIF11 si RNA to overcome the drug resistance of KIF11 si RNA,and studied its anti-tumor activity and synergic mechanism.The research content is divided into the following three parts:1)Construction and characterization of Co-delivery system of NIR-Ⅱautophagy regulator HD and si RNA.A Ph-responsive polymer was synthesized and a suitable co-inclusion method for HD and si RNA was explored.Nanoparticles were prepared by nano precipitation method with uniform particle size and good dispersion,and the encapsulation rates of si RNA and HD were 76.68%and 84.49%,respectively.Transmission electron microscopy showed that the nanoparticles were complete at PH=7.4.When PH=5.5,the nanoparticles depolymerized and released drugs,indicating that the nanoparticles had excellent p H responsiveness.2)In vitro anti-tumor activity and mechanism of co-delivered nanoparticles by NIR-Ⅱautophagy regulator HD and KIF 11 si RNA.In vitro experiments showed that i RGD was helpful to improve the uptake efficiency of the nanoparticle system by cells,and the Ph-responsive nanoparticles had good lysosome escape ability.The IC₅₀ values of KIF11si RNA and HD for Hep G2 cells were 24.39 n M and 716.7 n M,respectively.KIF11 si RNA co-delivered with HD has a significant synergistic therapeutic effect on Hep G2 cells.Studies have shown that HD@KIF11si RNA combined administration can inhibit the production of intracellular autophagy,thereby reducing the tolerance of tumor cells to stressful environments,further promoting the inhibition of KIF11 si RNA on cell mitosis,and accelerating the occurrence of apoptosis of Hep G2 cells.3)In vivo anti-tumor activity and mechanism of co-delivered nanoparticles by NIR-Ⅱautophagy regulator HD and KIF11 si RNA.In vivo experiments show that HD@KIF11 si RNA NPs can achieve non-invasive,high spatio-temporal resolution near-infrared two-zone fluorescence imaging in mice,with longer blood circulation time and excellent tumor targeting ability.In vivo antitumor studies showed that HD@KIF11 si RNA NPs combined administration group significantly inhibited the growth of tumor cells.Immunohistochemical and immunofluorescence histochemical results again confirmed the mechanism of synergistic therapy.In addition,the p H responsive nano drug delivery system has excellent biosafety and biocompatibility.This study provides a new drug combination scheme for the treatment of cancer,further promotes the development of multi-drug co-delivery strategy of nanocarriers,realizes the visualization of targeted delivery of nanocarriers system,and provides a new perspective for the application of the clinical integration of IR-II fluorophores.