Study On The Molecular Recognition,Properties,Synthesis And Activities Based On Cyclodextrin And VEGFR-2 Kinase

Cyclodextrins are cyclic oligosaccharides endowed with a hydrophilic outer surface and a hydrophobic inner cavity,able to form inclusion complexes with a wide variety of guest molecules,positively affecting their physicochemical properties.The molecular assembly and recognition of chemical modified cyclodextrins has become the important topic of supramolecular chemistry.In particular,in the pharmaceutical field,cyclodextrin complexation is mainly used to increase the aqueous solubility and dissolution rate of poorly soluble drugs,and to enhance their bioavailability and stability.Meanwhile,the analytical characterization of drug-cyclodextrin solid systems and the assessment of the actual inclusion complex formation is not a simple task and involve the combined use of several analytical techniques,whose results have to be evaluated together.The formation of tumor blood vessels in tumor growth and metastasis and evolution plays a very important role.Growth of solid tumors is dependent on continuous and extensive growth of blood vessels.Therefore,the inhibition of tumor angiogenesis can effectively inhibit tumor growth.In the process of tumor angiogenesis,vascular endothelial growth factor and vascular endothelial growth factor receptor interaction mediates its signal transduction pathway.Wherein,VEGF/VEGFR is the main control factor in regulating angiogenesis.There is already a variety of targeting VEGF/VEGFR signaling pathway specific tyrosine kinase inhibitor approved to medicine market and successfully used in the clinical treatment of tumors.This dissertation is composed of six parts:Part Ⅰ:A novel water-soluble oral satraplatin/β-cyclodextrin inclusion complex was prepared and characterized with a variety of techniques.Molecular Docking were performed to clarify its inclusion mechanism.Enabled by encapsulation with cyclodextrin,the water solubility of satraplatin was successfully increased to 7.4 mg/mL and significantly improved by phase solubility studies.Meanwhile,the stability of satraplatin in acidic and weak alkaline aqueous solution was also effectively enhanced by forming the inclusion complex.Importantly,in vitro cytotoxicity test,the satraplatin encapsulated complex has displayed superior cytotoxicity compared to free satraplatin against A549 and MCF-7 cells but almost non-toxic to Caco-2 cells.In vivo antitumor test,this satraplatin encapsulated complex has shown much better activity in repressing lung cancer than free satraplatin but nearly no-damage to intestinal mucosa by oral administration evaluated in xenograft mice models.Part Ⅱ:The inclusion complex of picoplatin with γ-cyclodextrin(γ-CD)was prepared and characterised by different analytical methods,including NMR,FTIR,TGA,phase solubility as well as SEM.All of these approaches indicated that picoplatin was able to form an inclusion complex with γ-CD,and that the picoplatin/γ-CD inclusion compounds exhibited different spectroscopic features and properties from free picoplatin.The stoichiometry of the complex was 1:1;the pyridine group of picoplatin was deeply inserted into the cavity of y-CD and the amine platinum group of picoplatin was near the narrower rim of y-CD.The calculated apparent stability constant of the complex was 10,318 M-1.Moreover,the water solubility of picoplatin was significantly improved,according to phase-solubility studies.The complex maintained its anticancer activity,as shown by an in vitro cell-survival assay on A549 and MCF-7 cancer cell lines.Part Ⅲ:Novel water-soluble inclusion complexes for fisetin(FIT)were developed by introducing β-cyclodextrin(β-CD)and y-CD.Properties of the obtained complexes,as well as the interactions between each component were systematically investigated in both solution and solid states by means of ESI-MS,NMR,FT-IR,XRD,DSC and SEM etc.All characterization information demonstrated that FIT/CDs inclusion complexes were formed,and exhibited different spectroscopic features and properties from FIT.A complex with 1:1 stoichiometry of FIT and CDs was confirmed with Job’s method.Meanwhile,as supported by molecular modeling calculations,we suggested that phenyl group(C ring)of FIT molecule was included in the CDs cavity from the wide side.Moreover,the water solubility of FIT/CDs was successfully improved from 2.8 mg/mL(in ethanol aqueous solution)to 4.5 mg/mL(FIT/β-CD complex)and 7.8 mg/mL(FIT/y-CD complex),and higher thermal stability results were shown by thermal analysis for those complexes.Notably,the inclusion complexes displayed almost two times higher cytotoxicity comparing to free FIT against Hela and MCF-7 cells.Part Ⅳ:The inclusion complexes of trans-polydatin(PD)with β-CD and γ-CD were prepared,and the PD/γ-cyclodextrin complex was discovered to have higher calculated Kc and Gibbs free energy(△G0)values by the phase-solubility diagram method,and the 1:1 stoichiometry of the complexes was visually proven with the phase-solubility diagram method and Job’s method.Molecular dynamics(MD)simulations were carried out to investigate the structure and dynamics of the 1:1 inclusion complexes formed by β-and γ-cyclodextrins(CD)with PD in water.The simulation results indicated that γ-CD provides the most stable inclusion complex of among all PD-CD complexes in this study.Similar to the MD results,the thermodynamics of the selected inclusion complex structure was calculated by semi-empirical and DFT methods.The statistical thermodynamics calculations also suggested that the PD/y-CD inclusion complex is a favorable binding mode and in good agreement with the experimental and MD data.Most importantly,the simulation results of present study are in good agreement with the experimental data.Consequently,the bioavailability of PD/CDs inclusion complexes were effectively improved over free PD in vitro.Part Ⅴ:Through Molecular Libraries Screening,the pharmacophore of indole the basic structure was found;and a virtual combination concentrate library of VEGFR-2 selective inhibitor were synthesized.The total of 39 compounds were synthesized and their structures were confirmed by related maps.We use chorioallantoic membrane model and MTT assay for the synthesis of compounds were screened,and we screened several compounds that can inhibit chorioallantoic membrane angiogenesis.Further studies showed that 21 f can inhibit the level of VEGFR-2 phosphorylation,and leading to the inhibition of down-stream signaling by the receptors like AKT,ERK,FAK,Src and other signaling molecules,and have a concentration-dependent manner.Part Ⅵ:Through Molecular Libraries Virtual Screening,it was found that the pharmacophore of benzamide as the basic mother nucleus structure.The virtual combination concentrate library of VEGFR-2 selective inhibitor was found,and one simple synthetic route was designed.At last,the 37 compounds of VEGFR-2 tyrosine kinase inhibitors with potential anti-tumor activity with the structure of the three fragments were synthesized.The compounds have never been reported and their structures are confirmed by related maps.Meanwhile,the chicken embryo blood vessel growth was tested,and the cytotoxicity of these compounds against HCT116 and A549 cells which were individually evaluated using the MTT assay.Experiment procedure,physical and spectral data for all compounds are recorded in section three.