Potent Inhibitors of Phosphatidylinositol 3 (PI3) Kinase that have Antiproliferative Activity Only When Delivered as Prodrug Forms

Prodrugs for PI3K: A series of substituted analogues of the phosphatidylinositol 3 kinase (PI3K) inhibitor LY294002 were prepared and found to potently inhibit the isolated enzyme but not MCF7 cell proliferation. Two tetrazolyl-substituted analogues were further derivatized as prodrugs resulting in restoration of cell-based activity. These data provide a conceptual model for development of tumor-targeting prodrug forms of cell-impermeable PI3K inhibitors.