Abstract 761: The development of cell permeable Shp2 PTP inhibitors

Protein tyrosine phosphorylation affects cellular activities that control tumor growth and progression. Protein tyrosine phosphorylation, a key regulatory process of signal transduction pathways, is controlled by the action protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Kinases are now a clinically proven anticancer drug target. The development of PTP inhibitors is, by comparison, a relatively new field. Since PTPs do not require a small molecule cofactor they generally show a low propensity to bind a small molecule inhibitor. Nevertheless there are now examples of highly potent PTP inhibitors that provide promising proof-of-principle that PTPs are druggable. Most PTP inhibitors have a charged or highly polar functional group that mimics the phosphotyrosine residue, that often leads to poor ADME and cell permeability properties. We will report our efforts to address the problems of cell permeability we have encountered in our Shp2 PTP inhibitor program. We have previously reported a series of isatin based Shp2 inhibitors based on a compound (NSC-117199) identified from screen of the NCI Diversity Set. We synthesized >100 analogs of NSC-117199 in our lead optimization effort, which yielded several compounds with approximately 50-fold increase in potency and > 10-fold increase in selectivity (Shp2 versus Shp1). However, these Shp2 PTP inhibitors have either a polar nitro or carboxyl group and have no detectable cellular activity. We will report three approaches to address this problem. The first approach was to prepare neutral ester prodrugs. Several compounds have clearly demonstrable activity against Shp2 in cells. A series of esters has also been designed to also improve the water solubility of the PTP inhibitor. A second approach taken was to further modify the isatin scaffold that does not necessitate the use of a prodrug strategy. We will report the discovery of new isatins related to NSC-117199 that have new modifications that result in cell active Shp2 inhibitors. Finally we will report the discovery and preliminary optimization of new classes of cell active Shp2 inhibitors based on alternative scaffolds. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 761.