Rational Design Of Engineered Fibroblast Membrane-based Delivery Platform For Efficient Cancer And Liver Fibrosis Therapy

Clinical anti-tumor nanomedicines have been proven effective in mitigating the side effects of chemotherapeutic drugs.However,most of the nanomedicines failed to fulfill their promise in augmenting the therapeutic efficacies due to the insufficient accumulation in target tissues.The major obstacle to the bioavailability of systemically administered nanomedicines is their sequestration primarily by mononuclear phagocyte system(MPS)which comprises Kupffer cells in the liver and macrophages in the spleen before they reach the target tissues.Thus,in the first part of this thesis(Chapter 2-4),a multi-functional biomimetic nanoplatform is designed to escape the sequestration of nanomedicines by MPS.Both optimizing the physichemical properties of nanomedicine and regulating MPS cells endocytosis,have been proved to be effectively in evading the sequestration of MPS and targeting tumor tissues.Polylactic-co-glycolic acid(PLGA)is an FDA-approved pharmaceutical excipient widely used in pharmaceutical field for fabricating nanoparticles in because of its good biocompatibility and biodegradability.However,PLGA nanoparticles are easily sequestrated in the MPS of liver and spleen upon entering the circulation.Cell membrane-based biomimetic nanoplatforms have been considered as a superior strategy to inhibit phagocytic clearance by macrophages and increase circulation time.Herein,membranes derived from human hepatic stellate cells(LX2)have been used for PLGANP coating,termed M-NPs.By taking advantages of the heterophilic adhesion between the N-Cadherin on fibroblasts membrane and E-Cadherin on tumor cells membrane,the resulted M-NPs significantly reduced the endocytosis of nanoparticles by macrophages and increased the uptake of MNPs by tumor cells.In addition,the membrane of LX2 was further engineered with the tumor necrosis factor-related apoptosis-inducing ligand(TRAIL).As a result,the TRAILexpressing cell membrane,TM coated nanoparticles(TM-NPs)could selectively induce the apoptosis of tumor cells through binding and activation of their cognate death receptor that specifically expressed in tumor cell membrane.The clinical antimalarial drug chloroquine(CQ)is now extensively used as an autophagy inhibitor in clinical trials for tumor combination therapies.Here we found that CQ can further inhibit the uptake of M-NPs by macrophages and synergized with TRAIL protein to induce tumor cell apoptosis.Therefore,the CQ was also embedded into the TM-NPs,forming TM-CQ/NPs(-200 nm,slightly negatively charged).In vitro cell cytotoxicity assays indicated that the TM-CQ/NPs remarkably induced apoptosis in tumor cells,but not in normal cells.Because of the reduced endocytosis of nanoparticles by macrophages and improved tumor accumulation,TM-CQ/NPs showed vigorous antitumor efficacy in two mice tumor models in vivo.Collectively,this cell membrane-based biomimetic nanoplatforms could effectively reduce MPS sequestration,successfully deliver therapeutic proteins(cell membrane expression)and small molecule drugs(inner core loading)to the tumor tissues,and significantly inhibit the tumor growth.Therefore,the multifunctional biomimetic nanoplatform provides a feasible strategy for precisely targeting tumor tissues and improving anticancer efficacy.Liver fibrosis is a global pathological problem without approved treatment.It is well established that the abnormal activation of hepatic stellate cells(HSCs)plays a central role in the development of liver fibrosis.Inducing the apoptosis of activated HSCs(aHSCs)or returning aHSCs to a more quiescent state have emerged as promising therapeutic approaches for liver fibrosis.Intriguingly,the death receptor(DR4 and DR5)of TRAIL is reported to highly expressed in the aHSCs rather than normal HSCs.Therefore,TRAIL protein might induce apoptosis of aHSCs,but spared other normal liver cells.Additionally,All-trans retinoic acid(ATRA)has been reported to successfully return the activated pancreatic stellate cells to the quiescent state by inhibiting the TGF-P pathway.Therefore,in the second part of this thesis(Chapter 5),TM-NPs were extended to the treatment of liver fibrosis,and the CQ was replaced by the ATRA,termed TM-ATRA/NPs.TM-ATRA/NPs induced apoptosis of aHSCs and reverted non-apoptotic aHSCs into a more quiescent-like state in vitro.TMATRA/NPs ameliorated the fibrosis and collagen deposition in a carbon tetrachlorideinduced mouse liver fibrosis model.Analysis of blood routine and staining of main organ revealed TM-ATRA/NPs had no hepatotoxicity and caused no obvious tissue lesions in main organs.