Synthesis Of A New Inhibitor Of Matrix Metalloproteinases And Analysis Its Inhibitory Effect To MMPs

Matrix metalloproteinases (MMPs) are a family of zinc dependent enzymes secreted that can degrade components of the extracellular matrix (ECM). There was a conservative sequence HEXGHXXGXXH containing three histidines in the MMPs'catalytic domain offering Zn2+ with coordinate bond and thus plays an important role in the catalytic activity of the enzyme. MMPs have emerged as critical molecules that degrade ECM components, other proteases, clotting factors, chemotactic molecules, growth-factor binding proteins, adhesion molecules, cell surface receptors etc. Thereby, MMPs mediate the synthesis and secretion of cytokine, growth factor, hormone, cell-cell adhesion molecules receptors and control cell migration, proliferation, morphogenesis and apoptosis and regulate tumor expansion, angiogenesis and dissemination. MMPs play important roles in many physiological and pathological processes, including angiogenesis, tissue remodeling, embryonic development, morphogenesis, arthritis, osteoarthritis and cardiovascular diseases, etc. MMPs are now known to contribute to multiple steps of tumor progression in addition to invasion and metastasis, including tumor promotion, angiogenesis, and the establishment and growth of metastatic lesions in distant organ sites. As MMPs involved in many pathological conditions, many MMP inhibitors (MMPIs) have been developed with the aim of interfering and treating diseases. Most of MMPIs are natural structure simulated to chelate zinc ion in the catalytic centre and inhibit its activity. However, because of the incomplete understanding of the function of MMPs, broad spectrum and side effects of MMPIs, though earlier studies can lead to highly effective inhibition of the activity of MMPs, and effectively prevent tumor growth and metastasis, clinical results are not satisfactory. Based on the understanding of the structure of MMPs, the ligand matching to S1' pockets in the catalytic domains may determine the inhibitory effect and specifity.We have screened out a new class of inhibitors, the experimental results proved that a key structure of pyrogallic acid can inhibit MMPs in vitro. Based on the analysis of the results, we found that there was no interaction between the pyrogallic acid and the catalytic zinc. But its binding site was in the S1' pocket.To study the mechanism of the inhibition, and find out if the structural modification improves the inhibition and specificity of pyrogallic acid, we synthesized a new compound 3-phenyl-1-(2,3,4-trihydroxyphenyl)propan -1-one(C₁₅H₁₄O₄, THBP). We intended to apply biochemistry, enzyme kinetics analysis, and computer simulation to study the inhibition effects and the mechanism of the class of the inhibitor.Experimental results showed that the change of the critical structur exhibits effective inhibitory activity on MMP-3, -13 and -16. The IC50 of THBP is 8.5μmol/L to MMP-3, 14.2μmol/L to MMP-13, and 7.1μmol/L to MMP-16. Docking result showes that there is no interaction between the molecule and the zinc of the catalytic domain, but binding into S1' pockets of catalytic domain, all of the 3 MMPs. Hydroxyls and carbonyl of the molecule provide as hydrogen bond donors, and thus increased the binding capacity and inhibitory effect of the inhibitor. This validates our experiment result of the mechanism of such new MMPIs. These studies will be helpful for design and optimization of the inhibitors and discovery for new active drugs.Research based on this thesis proved that the structure pyrogallic acid plays critical role in effective inhibition of the inhibitor. Study of the characteristics of such inhibitors will enable the discovery of similar structural, optimizing MMP inhibitors.Our research will accelerate pace of finding and synthesizing new MMPIs, and interpret the molecular mechanism of the new MMPIs.