Design And Synthesis Of Drug Targeting At Mitochondria And Its Basic Research On Application

Mitochondria are thought to have arisen about 1.5 billion years ago from a symbiotic association between a glyolytic proto-eukaryotic cell and an oxidative bacterium. Its major function include (i) energy production, (ii) calcium homeostasis, (iii) generation of reactive oxygen species (ROS), (iv) regulation of programmed cell death, or apoptosis. A vast amount of evidence points to the implication of mitochondria as a pharmacological target. The mitochondrial genome are very easily to be damaged by the surrounding environment owing to its genome have only exon. The mitochondrial dysfunction not only influence on the cell growth, metabolism, and proliferation, but also trigger the mitochondrial disease. Mitochondria play an important role in energy-generating, and manipulating the energy production. Therefore, the pharmacological target of mitochondria can be effective in treatment cancer cell and other diseases.Delocalized Lipophilic Cation have been explored as an approach to cancer chemotherapy that exploits their selective accumulation in mitochondria of cancer cells as a consequence of the elevated (△Ψm). DLC can pass easily through the lipid bilayer and their positive charge then directs them to the mitochondria where they accumulate at significantly higher concentrations than in the cytoplasm, owing to the large (△Ψm) generated by the respiratory chain. In addition to the increased (△Ψm), some cancer cells have been found to have higher plasma membrane potential (△Ψp) which further contributes to the increased uptake of DLC by cancer cells. F16, ((E)-4-(1H-indol-3-ylvinyl)-N-methylpyridinium iodide), a small molecule exhibiting the property of DLCs, selectively inhibits tumour cell growth and dissipating mitochondrial membrane potential discovered by Fantin. This work uses the properties of F16 as functional group or vehicles to delivery drug into cancer cell. The following major innovative works are carried out in the dissertation:1. F16 ((E)-4-(1H-indol-3-ylvinyl)-N-methylpyridinium iodide), a small molecule exhibiting the property of delocalized lipophilic cation (DLC), exhibits selective cytotoxicity toward transformed cells and induced cell apoptosis. Aiming at the photophysical properties of the different DLC related with the antitumour properties, we have synthesized the different position of pyridine conjugated with indole group. The bioactivities of three compounds inhibiting NPC cells were investigated by MTT. Steady-state absorption and fluorescence method have been used to characterize the binding of three DLCs (1,2,3) in reverse micelles and bovine serum albumin. The fluorescence and absorption data of 1 revealed that 1 penetrated into the interfacial region of the stern in reverse micelle,2 and 3 did not enter into the stern. From the experimental result, we can conclusion that DLC must possess a rigid structure coupling by double bond or benzene ring, in which the positive charge can be floated over the whole molecule. The present study of F16 derivatives in microenvironment would provide good information to develop the DLC.2. Aiming at optimization of the side effect property of 5-FU, we have designed F16 conjugated with 5-FU. The conjugate of F16-5-FU binding to bovine serum albumin (BSA) was investigated by fluorescence spectra, UV-vis absorption and molecular modeling study. Fluorescence quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between F16-5-FU and BSA. The activation energy of the interaction between F16-5-FU and BSA as much as 10.29 kJ mol-1 was calculated. F16-5-FU was about 2.95 nm far from the tryptophan according to the observed fluorescence resonance energy transfer between BSA and F16-5-FU. Site marker experiments show the binding sites of F16-5-FU most located in site II. The crystal structure of Human serum albumin (HSA) was used to simulate the drug binding site in molecular mode. Molecular docking calculated F16-5-FU binding to HSA in the site II, which was in agreement with the experimental results.3. In this section, we seek to combine the properties of F16 with the properties of porphyrin as PDT chemotherapy agents to create a highly active photosensitizer for use in chemotherapy. Reactions of the appropriate stoichiometric ratios of the bromide porphyrin and the precursor of F16 to give the targeting porphyrin A, B and C. The B is more efficacious in PDT than A, C and H2TMPyP. The percentage of the compound A induced cell apoptosis was 80%, but the percentage of apoptotic cell induced by the compound B was 12%. The quantum yield of Compound C is very low, so that its PDT in killing cancer cell is not effective, which is owing to the energy of porphyrin transfer to the metal Ytterbium (Yb). The solubility of A and B influence on its localization in cytoplasm, and show some aggregation. This study provide evidence that DLC as vehicles is very effective in PDT to delivery drug into cancer cell although the problem of solubility.4. In this section, we have developed a simple method to encapsulate QDs into micelle-like amphiphilic polymers, without modifying or replacing the inorganic coating. This shell coating can increase the solubility of QDs in aqueous medium, reduce leaching of metals from the core, and facilitate customized surface chemistry for the attachment of conjugates to therapeutic and diagnostic macromolecules. The mode of energy transfer between QDs and TPyP is non-FRET, and the porphyrin quenching QDs of the one photon is more effective than that of two photon. The efficiency of generating single oxygen (1O2) in aqueous solution can be determined indirectly by measuring the decrease of fluorescence of disodium salt of 9,10-anthracenedipropionic acid (ADPA). The ratio of generating single oxygen of QDs-TPyP is higher than that of QDs, and TPyP. It clearly demonstrates that QDs-TPyP is an effective photosensitizing agent under two-photon-excitation conditions (λex=800 nm). The 1O2 of QDs is very low, indicating that the amphiphilic polymers-encapsulated QDs is very stable during irradiation.