Template Based Design of Anti-Metastatic Drugs from the Active Conformation of Laminin Peptide II

摘要

Additional work has been conducted to elucidate the structure of the peptide 11 binding pocket in the 67 kDa LBP. Limited proteolysis experiments on the rLBP indicated that all the regions, identified last year by phage display as interacting with peptide 11, were surface exposed on the folded protein. We found that the recombinant protein exhibited partial aggregation driven by disulfide bond formation at the very high concentrations needed for NMR spectroscopy, and we have created mutant rLBP lacking Cys residues to alleviate this problem. The candidate 16 mimetic has been synthesized, as well as a useful structural relative which can be produced in many chiral variants for determining the optimal geometry for anti-invasive activity. We found that ER +ve tumor cells shed LBP in amounts proportional to their invasive abilities. 17 beta estradiol promoted LBP shedding, and addition of exogenous shed or rLBP promoted invasion by ER +ve breast and ovarian cancer cells. LBP shedding may turn out to be a new therapeutic target. The LBP protein was found to have sulfhydryl oxidase activity, a finding potentially related to the optimal activity of peptide 11 dimer and the loss of activity in the Ser for Cys peptide 11 analog.