Design and synthesis of tyrosine phosphate peptide and peptidomimetic prodrugs

Hugo Garrido Hernandez, Purdue University

Abstract

Several phosphoramidate prodrugs that target the SH2 domain of p56 lck have been developed. The novel development was originated from studies with model cresyl phosphoramidates. The prodrugs incorporate a phospho-ester delivery group, a phosphor amide masking group and a phospho-ester effector. Enzymatic activation of the prodrugs eliminates the delivery group, and the transformation induces the masking group to become unstable and ultimately drive to the rapid and quantitative formation of the phosphorylated effector. The first generation of phosphoramidates created presented inhibitory activities in the low micromolar range in a cell-based T cell receptor signaling model. The difference in activity between parent compound and prodrug was found to be 6-fold suggesting an increased cellular uptake of the prodrugs. A second generation of novel phosphorodiamidates was also synthesized. The phosphorodiamidates were designed to generate enzymatically stable NH-phosphates after activation. However, they were found to be less stable than their corresponding O-phosphates and presented a half-life of about 40 min at room temperature. These phosphorodiamidates inhibited T cell signaling in the micromolar range with a decreased potency of approximately 10-fold when compared to their corresponding O-analogs. The phosphorylation of ZAP70, a reaction catalyzed by Lck and required for T-cell signaling, was found to be inhibited by the phosphoramidates in a dose-dependent manner. Finally, this strategy was also applied for the generation of a masked phosphotyrosine reagent that was incorporated into solid phase peptide synthesis.

Degree

Ph.D.

Advisors

Borch, Purdue University.

Subject Area

Pharmacology

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