The Study Of PSMA-targeted Delivery System For Prostate Cancer Therapy

Prostate carcinoma, prostatic cancer（Pca）is the most common malignant tumor in malereproductive system. Presently, clinical methods curing medium-term or late-term Pca areradiotherapy, chemotherapy(inc endocrine therapy),etc. However,these therapies got problemslike poor medication compliance,poor tissue selectivity, strong toxic reaction, resistance andso on. Thus, compare with the above methods, gene therapy has many incomparableadvantages,such as good targeting, tiny toxicity and side effect as well as killing tumor cellsspecifically.For exogenous gene can not get access to cell initiatively, the gene therapy stillneeds a safe and high-efficiency delivery vector to delivery when applying to clinic.Alongwith the development of targeted drug delivery system, the combined usage of targeted drugdelivery system and gene therapy gradually becomes a hotspot in the field of biotech drugs,and is considered to be the most promising research direction in cancer therapy.This study draws up nanoparticle PAMAM as drug carriers, miR-15a and miR-16-1asmodel drug, aptamer A10-3.2as prostate-targeting ligand, PSMA as target, and all theseco-construct PSMA-mediated targeting nanoparticle polymer APT-PEG-PAMAM,and takefurther study on its anti-Pca mechanism. Specifical aptamer attached to the surface of thenanoparticle that can target to Pca cells by aptamer-oriented role so that it can change thedistribution of drugs in vivo tumor tissue or in non-tumor tissue, improve the therapeuticindex,and reduce the side effect. The use of PAMAM carrier of low cytotoxicity entrapmiR-15a-miR-16-1,while multi-target effect in Pca cells. Compared with monotherapy, thistherapy has better effectiveness. Meanwhile, chaptered one uses PSMA monoclonalantibodies as targeted head group, having synthetized mAb-PEG-PAMAM,and compared itwith APT-PEG-PAMAM to set forth the differences between the two.The first part shows that the firstly synthesized PEG-modified poly cationic vectorPEG-PAMAM, can confront the electropositivity of PAMAM on the one hand, so as to lowerits toxicity; on the other hand, PEG-PAMAM, which is being used as a gene vector, can stay longer in vivo. Secondly, contributing an unprecedent prostate-targeting nano-scale genedrug-delivery system, which consists of the linking between PEG-PAMAM and monoclonalantibody (mAb)of a kind of antibody [YPSMA-1] that can identificate PSMA specifically.Next, compared mAb-PEG-PAMAM with another kind of newly targeting gene vectorPAMAM-PEG-APT mentioned in the second part, thereafter we can evaluatePAMAM-PEG-APT objectively. The active targeting drug-delivery system on the basis ofmAb being targeting ligand cannot be developed due to its immunogenicity, costly expenses,high molecular weight and other shortcomings.In the second part, NHS-PEG-MAL and PAMAM were selected to synthesizeNHS-PEG-PAMAM. The reaction condition between NHS and SH was mild, as a result,APT-SH was designed by biological corporations which can be reagent, together withNHS-PEG-PAMAM mentioned above, to synthesize APT-PEG-PAMAM and the process cansimply avoid decreasing the activity of APT. Eventually, the transfection efficiency andtargeting of APT-PEG-PAMAM would be investigated. PAMAM-PEG-APT was applied asmacromolecular polymer to encapsulate DNA to synthesize PAMAM-PEG-APT/DNAnanoparticle which has a particle size around180nm and zeta potential around18mV. It isspherical and has regular shape and high stability under the examination of electronmicroscope. The modification of APT significantly enhanced the transfection efficiency ofPAMAM-PEG-APT/DNA in both prostate cells which can highly express PMSA and LNCaPcells. PAMAM-PEG-APT/DNA has a series of advantages, such as high stability, small size,obsolete immunogenicity and so on, and these all makes APT functioning as target ligand inprostate-targeting drug-delivery system a bright future.The third part illustrates a new type of nanoparticle active targeting drug-delivery systemPAMAM-PEG-APT/miRNA which is on the basis of genetaceuticals microRNA-15a andmicroRNA-16-1that can inhibit the growth of androgen-dependant prostate tumor cellLNCaP,then encapsulated them into PAMAM-PEG-APT which is being used as genevector, finally evaluated the effect of inhibition of the growth of androgen-dependantprostate tumor and safety. the result shows that PAMAM-PEG-APT/miRNA has better targeting ability，better prevention from proliferation of prostate tumor cells which hassignificant differences in contrast to the other3control groups. The results of the detection ofhepatic and renal function demonstrate that there is no significant differences between thesefour group (P>0.05), meaning that PAMAM-PEG-APT/miRNA targeting drug-deliverysystem,compared to chemotherapeutic drugs, is a new safer gene therapeutic drug because ithas no obvious toxicity in liver and renal.All in all, this study draws up nanoparticle PAMAM as drug carriers, miR-15a andmiR-16-1as model drug, aptamer A10-3.2as prostate-targeting ligand, PSMA as target, andall these co-construct A10ligand-directed targeting nanopartical polymer(APT-PEG-PAMAM), and take further study on its anti-Pca mechanism. The results illustratethat compared to antibody-modified nanoparticle drug-delivery system(PAMAM-PEG-mAb/miRNA), ligand-modified nanoparticle drug-delivery system(PAMAM-PEG-APT/miRNA)can enhance the targeting ability and has higher activity inkilling tumor. Meanwhile, owing to its high safety, high stability, easy process of synthesis,low cost price, the synthesis of PAMAM-PEG-APT/miRNA provide evidence in both theoryand practice so as to develop active targeting drug-delivery system aiming at prostatic cancer.