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Delivery Of Nucleic Acid Drugs With Nanoparticular Systems For Cancer Therapy

Posted on:2013-04-15Degree:DoctorType:Dissertation
Country:ChinaCandidate:X Q LiuFull Text:PDF
GTID:1221330377451770Subject:Biological materials
Abstract/Summary:PDF Full Text Request
The tumor progression is a complex procedure and there are various types of treatments. Therapeutics based on nucleic acid drugs are the uses of DNA, siRNA, miRNA or etc. as pharmaceutical agents to implement functions of some important genes or down-regulate expression of oncogenes. However, the in vivo delivery of nucleic acid drugs to target tissues and cells remains the biggest challenge for its clinical applications. In this dissertation, different nanoparticle systems have been developed for systemic delivery of nucleic acid drugs for cancer therapy. These delivery systems can efficiently carry plasmid DNA, anti-miRNA antisense oligonucleotide or siRNA into specific cells, and exhibit remarkable tumor growth inhibition capacity both in vitro and in vivo.In the first part, a brush-shaped polymer PHEMA-g-(PEI-b-PEG) with poly(2-hydroxyethyl methacrylate)(PHEMA) backbone and linear poly(ethylenimine)-b-poly(ethylene glycol)(PEI-b-PEG) side chains was synthesized and evaluated as a vector for potential p53gene therapy. PHEMA-g-(PEI-b-PEG) was much less cytotoxic when compared with branched poly(ethylenimine) with Mw of25kDa. The capacity of plasmid DNA condensation by PHEMA-g-(PEI-b-PEG) was demonstrated and they formed nanosized complexes. The complexes of PHEMA-g-(PEI-b-PEG) with plasmid DNA were more efficiently internalized by BT474cells in comparison with the complexes of PEI25K, leading to higher gene transfection in cells. Further investigation using complexes of PHEMA-g-(PEI-b-PEG) with plasmid DNA encoding wild-type p53gene showed its potential as a carrier for cancer gene therapy. The complexes of PHEMA-g-(PEI-b-PEG) successfully induced elevated wild-type p53expression in BT474cells, led to enhanced apoptosis of BT474cells and also significantly increased the sensitivity of BT474cells to doxorubicin chemotherapy.In the second part, we reported a PEGylated LPH (liposome-polycation-hyaluronic acid) nanoparticle formulation modified with cyclic RGD peptide (cRGD) for specific and efficient delivery of AMO into endothelial cells for anti-angiogenesis therapy. The nanoparticles effectively delivered anti-miR-296AMO to the cytoplasm and downregulated the targeted miRNA in αvβ3integrin positive endothelial cells, which further efficiently suppressed blood tube formulation and endothelial cell migration, owing to significant upregulation of hepatocyte growth factor-regulated tyrosine kinase substrate (HGS). In vivo assessment of angiogenesis using Matrigel plug assay also demonstrated for anti-angiogenesis effect. With the delivery of anti-miR-296AMO by targeted nanoparticles, significant decrease in microvessel formulation within Matrigel was achieved through suppressing the invasion of CD31-positive cells into Matrigel.In the third part, we reported a cationic mixed micellar nanoparticle (MNP) consisted of amphiphilic block copolymers poly(s-caprolactone)-6lock:-poly(2-aminoethylethylene phosphate)(PCL29-b-PPEEA21) and poly(ε-caprolactone)-block:-poly(ethylene glycol)(PCL40-b-PEG45) as a suitable siRNA carrier to inhibit tumor growth by suppressing expression of hypoxia inducible factor-la (HIF-la). MNP loaded with HIF-la siRNA (MNPsiHIF) could transfect PC3prostate cancer cells efficiently, block cell proliferation, suppress the cell migration and disturb the angiogenesis under in vitro mimicked hypoxic condition. It was further demonstrated that systemic delivery of MNPsiHIF effectively inhibited tumor growth in a PC3prostate cancer xenograft murine model. Moreover, delivery of MNPsiHIF sensitized PC3tumor cells to doxorubicin chemotherapy in vivo by down-regulating MDR1gene expression which was induced by hypoxia.
Keywords/Search Tags:gene therapy, anti-miRNA antisense oligonucleotide, siRNA, nanoparticle delivery system, cancer therapy, angiogenesis, tumor hypoxicmicroenvironment
PDF Full Text Request
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