Design, Synthesis And Screening Of Small Molecule CCR4 Antagonists

Chemokines and their receptors play an important role in inflammation, tumor, autoimmune diseases, allergy and HIV infection. So far, about 50 species of human chemokines and about 20 kinds of chemokine receptors has been obtained by cloning. With the completion of the Human Genome Project and the development of orphan receptor program, the amount of chemokines and their receptors will continue to increase, therefore the research on this field research has great theoretical significance and application value. Some of the reorganized chemokines, chemokines and their receptor antagonists which have entered the clinical research have become new biological treatment hot spots.CC chemokine receptor 4 (CCR4) is a kind of G-protein-coupled receptors with a characteristic seven-transmembrane structure and selectively expressed on Th2-type CD41 T cells, which was found in 1995. It has 3 natural-specific ligands, among which Thymus and activation regulated chemokines (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22) positioned on the 16q13 region of 16th human chromosome have a high affinity to CCR4, and their Kd values were 0.5nm and 0.18nM separately. The third natural CCR4 ligand, Chemokine-like factor 1(CKLF1), a new cytokine which was found in July 2001, positioned on the 16q22 region of 16th chromosome has very different structure and expression from TARC and MDC and its in-depth study is now in progress.CCR4 plays an important role in autoimmune diseases, allergic inflammation, thrombotic diseases etc.. The small molecule CCR4 antagonists synthesized by now are: flavanone thiazole compounds, lactam compounds, 2 - aminothiazoles compounds, sulfonyl aryl amines, diamino-pyrimidine, as well as cyclic amine. At present, Chemokine receptor antagonists in Phase I Clinical Trial Service are CXCR2, CXCR4, CCR1 and CCR5 antagonists, but not CCR4 antagonists. Therefore the research of activie and selective small molecule CCR4 antagonists is conducive not only to study CCR4 biological function, but also beneficial to explore the development of new drugs with CCR4 as a potential drug target, especially in the anti-asthma drugs, and has broad research, development and application prospects.Since no experimentally determined three-dimensional CCR4 structure is currently available, we modeled the structure of CCR4 based on the structure of 1U19A protein of bovine rhodopsin. By analysis of its structural characteristics and the characteristics of ligand interaction, using Me Too strategy and computer- assisted drug design methods; we designed and synthesized 30 compounds, among which 22 are lactam compounds and 8 ester compounds. All the compounds synthesized have two chiral carbon atoms. We have used Chiral Synthesisl method, directly obtaied the R, R configuration of the enantiomers, thus avoided separation of chiral compounds and the use of chiral separation column. At the same time, by the use of 2D 1H-1H COSY spectra and 1D-NOESY spectrum the absolute configurations of these compounds have been determined. This method is convenient, easy, economic and efficient.Capillary Electrophoresis results showed that 9 compounds have strong combination with the receptor, among which 6 compounds have strong MDC- mediated inhibition of CCR4-transfected HEK293 cells chemotaxis.1 compound has an significant inhibitory effect similar to that of the positive compound. It has the value for further research. There is an ester compounds showed good activity. This indicates that the esters have the value of research and development. MTT results show that the toxicity of optimization compounds lower than positive compound or equivalent. We analyzed the structure-activity relationship of compounds. This provides a theoretical basis for the next work.