PI-103

6- to 12-week-old Balbc nu/nu mice bearing U87MG:deltaEGFR cells

Phenol, 3-[4-(4-morpholinyl)pyrido[3', 2':4, 5]furo[3, 2-d]pyrimidin-2-yl]-

PI-103 is a potent, ATP-competitive PI3K inhibitor of DNA-PK, p110alpha, mTORC1, PI3KC2beta, p110delta, mTORC2, p110beta, and p110gamma with IC50 of 2 nM, 8 nM, 20 nM, 26 nM, 48 nM, 83 nM, 88 nM and 150 nM, respectively.

PI-103 represents the first potent, synthetic mTOR inhibitor.

2 nM, 2 nM, 2 nM, 2 nM, 2 nM, 2 nM

When tumors reach 50-100 mm3, animals are randomized and treated with vehicle or PI-103. PI-103 exhibits significant activity, decreasing average tumor size by 4-fold after 18 days. [2] Mice treated with PI-103 have no obvious signs of toxicity premorbidly (based on body weight, food and water intake, activity, and general exam) or at necropsy. Treated tumors display decreased levels of phosphorylated Akt and S6, consistent with blockade of p110alpha and mTOR. PI-103 treatment is cytostatic to glioma xenografts. [2]

Assay of p110 kinase, Reactions are initiated by the addition of ATP containing 10 uCi of gamma- 32P-ATP to a final concentration 10 or 100 uM, and allowed to proceed for 20 minutes at room temperature. For TLC analysis, reactions are then terminated by the addition of 105 uL 1 N HCl followed by 160uL CHCl3:MeOH (1:1). The biphasic mixture is vortexed, briefly centrifuged, and the organic phase transferred to a new tube using a gel loading pipette tip precoated with CHCl3. This extract is spotted on TLC plates and developed for 3-4 hours in a 65:35 solution of n-propanol:1 M acetic acid. The TLC plates are then dried, exposed to a phosphorimager screen, and quantitated. For PI-103, kinase activity is typically measured at 10-12 inhibitor concentrations representing two-fold dilutions from the highest concentration tested (100 uM). For PI-103 showing significant activity, IC50 determinations are repeated two to four times, and the reported value is the average of these independent measurements.

348, 36

Data from [Mol Carcinog, 2012.April, ahead of print], PI-103purchased from Selleck, (A) MCF7 cells pre-treated with 100 nM siRNA for 72 h were re-seeded with normal growth media and grown overnight, then further transfected by 100nM of fresh siRNA. Twenty-(A) four hours after transfection, the cells were further treated with PI-103 for 24 h and the cell lysates were immunoblotted with the indicated antibodies. (B) Breast cancer cells carrying BRCA1 mutations were treated with 1 mM of PI-103 for 24h (left) or increasing amounts of PI-103 for 24 h (right). Cell lysates were analyzed by Western blotting with the indicated antibodies.

DMSO 24 mg/mL, Water <1 mg/mL, Ethanol <1 mg/mL