Application Of RGD-mediated Environmentally Sensitive Micelles In The Treatment Of Non-small Cell Lung Cancer

Nano-polymer micelles drug delivery system based on self-assembly of amphilic block copolymers has been widely reported in the treatment of cancer in recent years,which possesses wide range of drug loading,flexible structure,tumor targeting effect and high stability.Environmental sensitive micelles could target to tumor site specifically and respond to the tumor microenvironment which results in pinpointed and fast intracellular drug release.In addition,the environmental sensitive micelles could reduce drug accumulation in normal tissue and cells,which reduce the side effect.In this study,two kinds of polymer materials with different responses to the tumor environment were synthesized by rational molecular design.And two kinds of treatment strategies,including single chemotherapy and the combination of chemotherapy and gene therapy were designed to explore the character and advantages of environmental sensitive micellar delivery system in the treatment of NSCLC.Charpter 1:The development of tumor targeting nano delivery systems was briefly introduced.The nano delivery system in response to tumor microenvironmental in recent years was summarized.And the advantage of gene and drug combination therapy for tumor was expounded.The research background and the design ideas of this paper were based on the review.Charpter 2:An amphiphilic copolymer N-palmitoyl-N-succinyl-chitosan(SPCS)was synthesized and characterized.cRGDyK peptide is a ligand that can target tumors via specific binding integrin receptor overexpressed on tumor neovascularization and cells.cRGDyK-functionalized SPCS micelles loaded with paclitaxel(cSPCS/PTX)were prepared by film dispersion method and then characterized in terms of morphology,size,and zeta potential.The average particle size of cSPCS/PTX micelles was 138.8 nm and TEM morphology showed the particles were uniform and round at pH 7.4.cSPCS/PTX micelles presented pH-triggered drug release behavior in vitro.The cellular uptake results detected by the confocal laser scanning microscope and the flow cytometry illustrated that cRGDyK modification enhanced the internalization of micelles by luc-A549 cells.Meanwhile,co-localization of the micelles and lysosomes was recorded dynamically using a live cell station.MTT assays and cell apoptosis studies revealed that cell viability was significantly inhibited by cSPCS/PTX micelles.More importantly,in vivo animal imaging studies showed that cSPCS micelles mainly accumulated in the orthotopic tumor site.cSPCS/PTX micelles exhibited better anti-tumor activity against subcutaneous and orthotopic lung tumors compared with PTX/SPCS micelles and Taxol~?.These results suggested that cSPCS/PTX micelles had better cancer targeting capacity and superior anti-tumor efficacy.Charpter 3:In this study,we developed a tumor microenvironment sensitive micelles delivery system based on the assembly of pH/redox dual-sensitive polymeric materials((cRGDyC-PEG)-(CS-PEI)-LA,cPCPL)for the co-delivery of EZH2 siRNA and ETP to orthotopic NSCLC.The micelles exhibited dual pH/redox sensitivity verified by particle size,morphological changes,and in vitro release of drugs.Confocal microscopy analysis confirmed that the micelles exhibited endosomal escape property and on-demand intracellular drug release behavior,which can protect siRNA from degradation and facilitate the chemotherapeutic effect.In vitro tumor cell motility study demonstrated that siRNA can decrease the migration and invasion capabilities of tumor cells by downregulating the expression of EZH2 gene and protein.In particular,an antiproliferation study revealed that the co-delivery of siRNA and ETP can induce a synergistic therapeutic effect on NSCLC.In vivo targeting evaluation showed that cRGDyC-PEG modification on micelles caused a low distribution in normal organs and an obvious accumulation in orthotopic lung tumor.Furthermore,targeted micelles co-delivering siRNA and ETP showed superior inhibition on tumor growth and metastasis and produced minimal systemic toxicity.These findings indicated that pH/redox dual-sensitive micelles could be utilized as a co-delivery system,and that the combination of EZH2 siRNA and ETP could be an effective strategy for the treatment of NSCLC.