The Study Of Targeting Tumor Tissue And Cellular Uptake Behavior Of Nanomaterials

There is widespread and urgent demand for anti-tumor nanomedicines,but the nanomedicines currently used clinically can only reduce the toxic and side effects of the drugs,facing the dilemma of their failure to improve the therapeutic efficacy.The main obstacle is the nature of uncontrolled biological fate of nanoparticles,leading to non-active tumor cell uptake and unregulated intracellular trafficking.Nanoparticles are often functionalized with targeting ligands to specifically target tumor cells and enhance their cellular uptake via receptor-mediated endocytosis.However,most of the cell-surface receptors currently used are less efficient at endocytosis,resulting in inefficient uptake of nanoparticles by cells.In addition,the internalized nanoparticles often face the issue of lysosomal trapping,where the acidic and proteolytic enzymerich environment sequesters and degrades the nanoparticles,resulting in reduced delivery efficiency to the cytoplasm or nucleus.Therefore,there is an urgent need for an efficient delivery strategy that can simultaneously achieve rapid cellular uptake and non-lysosomal intracellular trafficking.Nutrient transporters are receptors with transport activity that are highly efficient in endocytosis and have evolved unique nutrient signaling functions.Several delivery strategies targeting nutrient transporters overexpressed on the surface of tumor cells have been developed to achieve rapid uptake of nanomedicines by tumor cells.However,due to the natural trafficking patterns of these nutrient transporters,nanomedicines are still transported to lysosome.We envision that nutrient transporter that concurrently possess natural non-lysosomal transport pathway and tumor-specific overexpression may represent a more attractive and valuable targeting delivery approach.In addition,for non-active targeting nanoparticles,modulating the mechanical properties of the nanoparticle can significantly affect their interaction with the cell membrane,thereby achieving rapid cellular uptake.This dissertation can be categorized into two parts,Chapter 2-4 in this thesis mainly constitute the first part.In this part,we first verified the high dependence of tumor cells on foreign cholesterol,and then analy zed the characteristics of cholesterol metabolism in lung cancer and liver cancer through bioinformation technology,finding that cholesterol transporter NPC1L1 is highly expressed in lung cancer and liver cancer and is associated with poor prognosis.qRT-PCR,WB and flow cytometry were used to verify that the mRNA and protein expression of NPC1L1 in common lung cancer and liver cancer cell lines was higher than that in normal cells.In Chapter 3,using NPC1L1 as the drug delivery target,we constructed model cholesterol surface-display nanoparticles(CSD-NPs)based on adjacent hydrophilic molecular engineering strategies.The results of 1H-NMR,angle-resolved XPS and ITC showed that the cholesterol moiety displayed on the surface of CSD-NPs had high degree of freedom and molecular recognition function.Molecular docking simulation revealed that cholesterol displayed on the surface of CSD-NPs had binding activity with NPC1L1.Cellular uptake experiments showed that CSD-NPs had tumor-specific rapid cellular binding and internalization capabilities.Finally,the molecular mechanism of NPC1 L1-mediated non-lysosomal pathway of CSD-NPs uptake was elucidated.In Chapter 4,we established the cholesterol surface-display functionalized nanomedicine Doxil-Chol based on the NPC1L1-mediated non-lysosomal pathway of CSD-NPs uptake.The characteristics of Doxil-Chol,such as cellular uptake,cytotoxicity,blood clearance,in vivo distribution,anti-tumor activity and biosafety,were studied.The results revealed that Doxil-Chol had significantly enhanced cellular uptake and in vitro cytotoxicity,showing excellent anti-tumor activity at low doses.In the second part of this thesis,we designed and synthesized a series of negatively charged polymeric nanomicelles with different core rigidity to study the effect of core rigidity of polymeric nanomicelles on cancer cell uptake.The results showed that tuning the core rigidity of negatively charged polymeric nanomicelles could improve the cell uptake efficiency,and the core rigidity and surface charge had a combined effect on modulating cancer cell uptake.