Cationic Polymer Pc Coupling Small Molecule Drugs Synergistic Anti-tumor Activity Of The Gene Study

Currently, chemotherapy is indispensable to anticancer. But pharmaceutical drug's clinical applications were limited because of its toxic side effects, low water-solubility, nontarget, etc. With the rapid development of novel polymer materials in the field of modern medicine and pharmacology, polymer materials used as the carriers of anticancer drug could not only improve drug water solubility to a great degree, increase pharmaceutical bioavailability and reduce the number of drugs injection, but also control the release rate of the drug efficiently in vivo. Though the good results were achieved, the drug-resistance. problem has arisen when low molecular weight anticancer drugs were used continuously. With the improvement of the molecular biology measure, researchers found out that cancer could be cured by the way of putting human normal gene or therapeutic foreign gene into human target cells for efficient expression of gene and correcting defective gene. Therefore, gene therapy has become the effective methods for anticancer. Concerned for immunogenicity, the organic combination and application of gene therapy and other methods, such as surgical operation, radiation therapy, chemotherapy and interventional therapy could not only overcome multidrug resistance, but also make excellent performances and synergism.Our aim is to design and synthesize polycation PC as carriers with high gene expression efficiency, which anticancer drug could be conjugated for decreasing its toxic side effects, improving bioavailability. Condensed with therapeutic gene plasmid via static electricity, the growth of tumor could be inhibited by synergistic function via tumoral local injection of PC-drug and plasmid condensation. Firstly,β-cyclodextrin-grafted polyethylenimine (PC) was synthesized by reaction of CDI activatedβ-cyclodextrins (CD) with the characteristic of less side effect, better biocompatibility, high gene transfection efficiency and biodegradability.5-fluoro-2'-deoxyuridine (FdUrd) is a new-developed prodrug of 5-fluorouracil (5-Fu), which was made from the dehydroxylation of nucleoside on 5-carbohydrate. After the fluorouracil drug was taken in the past, the 5-Fu was transferred and took function by the way of liver drug metabolizing enzymes or natural decay. Nevertheless, the marked characteristic is that it could be transferred into 5-Fu by high active Pyrimidine-Nucleoside Phosphorylase (PyNpase) in tumor tissue. For the purpose of reducing the toxic side effects with drug orally and vein injection of FdUrd, enhancing the bioavailability of drug, decreasing the number of injection, prolonging the drug release in tumor, a series of FPC with different volume of FdUrd were synthesized by controlling the ratio of reaction materials. And the conjugations could be biodegradable due to the peptide bonds connected. The properties have be determined by using 1H NMR, UV, GEL, particle-size, zeta potential and drug degradability, etc. MTT cytotoxicity identified FPC could inhibit glioma cells growth. And the cell uptake tests proved that FPC have high bioavailability and can be uptaken by cells in short time. The experiments imitating wound condition after tumoral operation (cell wound-scratch, migration and invasion tests) investigated that FPC have the greater function to inhibit the cells migration. And the cells apoptosis and cell cycle were determined by flow cytometer after the cells incubated by FPC. Because FPC condensed with pEGFP and Luciferase gene plasmid could make gene transfection efficiently, these results had made it possible that drug and gene could be carried to the same cell and tissue using the polymer PC. Then, the pEGFP gene expression could be done by locally tumoral injection of the condensation of FPC/pEGFP and the expectation results had been proved. The significance of this section is FPC conjugation condensed with gene plasmid, could not only enhance the drug bioavailability, reduce side effects, prolong the time of drug release, but also the gene carried by FPC could make a further therapeutic function for apoptosis and inhibition on tumor.Since the wide application of various chemotherapeutic drugs, the problem of drug resistance has been more and more serious and became one of the main obstacles. Though the combination of multiple drugs was adopted to inhibit the tumoral growth, multidrug-resistance could be still arisen for some cancer, such as breast, lung cancer and so on. For further treatment, doxorubicin was conjugated with polycation PC and the conjugation PC-Dox was used as p53 gene vector, then the condensation PC-Dox/p53 was tested to determine the capability of inhibits doxorubicin resistance breast cancer for the synergistic effect.PC-Dox were designed and synthesized with different ratios of reaction materials by the way of doxorubicin conjugated to the main chain of polymer PC. The properties were determined by the means of 1H NMR, UV, GEL, particle-size, zeta potential and so on. MTT cytotoxicity identified that PC-Dox could inhibit breast cancer cells growth during 48 h, effectively. PC-Dox has been determined to make great cell uptake capability via the cell uptake tests. And the high gene transfection efficiency has been proved when PC-Dox condensed with pEGFP and Luciferase gene plasmid. Western blot and RT-PCR experiments tested that PC-Dox/p53 condensation could improve and enhance the protein expression. After the Balb/c mice were injected with PC-Dox/p53 solution on local tumor with the optimum ratio of synergistic effect of drug and gene, the survival rate, weight and tumor weight of mice were investigated for 45 days. The results showed that this method could inhibit the breast drug-resistant cancer growth to great extent, prolong the mice survival and reduce the drug toxic side effect effectively.The research above indicated that the polymer PC is drug and gene carrier with better properties, and it could not only enhance drug water solubility, increase pharmaceutical bioavailability, but also delivery gene into cell efficiently. PC could delivery drug and gene into the same cell or tissue and take function with the release drug from PC to limit the cancer cell growth and migration, at the same time the gene expressed in the cells could overcome the drug-resistance and make the synergistic therapeutic effect. Therefore, our study has a great significance for cancer clinic therapy.