Molecular Weight (MW)

382.42

Formula

C18H22N8O2

CAS No.

1382979-44-3

Storage

-20℃ for 3 years in powder form

-80℃ for 2 years in solvent

Solubility (In vitro)

DMSO: 8 mg/mL (20.9 mM)

Water: <1 mg/mL

Ethanol: <1 mg/mL

Other info

Chemical Name: 5-(6,6-dimethyl-4-morpholino-8,9-dihydro-6H-[1,4]oxazino[4,3-e]purin-2-yl)pyrimidin-2-amine
InChi Key: LGWACEZVCMBSKW-UHFFFAOYSA-N
InChi Code: InChI=1S/C18H22N8O2/c1-18(2)16-22-12-14(25-3-6-27-7-4-25)23-13(11-9-20-17(19)21-10-11)24-15(12)26(16)5-8-28-18/h9-10H,3-8H2,1-2H3,(H2,19,20,21)
SMILES Code: NC1=NC=C(C2=NC(N3CCOCC3)=C4N=C(C(C)(C)OCC5)N5C4=N2)C=N1

Synonyms

Paxalisib; RG7666; RG-7666; RG 7666; GDC-0084; GDC0084; GDC 0084.

In Vitro

In vitro activity: GDC-0084 has excellent human metabolic stability in microsomal and hepatocyte incubations and demonstrated inhibition of pAKT, a key signal within the PI3K pathway, in normal brain tissue. GDC-0084 is shown to inhibit the proliferation of several glioma cells in vitro with IC50 ranging from 0.3 to 1.1 μM. GDC-0084 binding to plasma proteins is low, with a free fraction (%) of 29.5±2.7 (n=3) in CD-1 mouse plasma, when tested at 5 μM. Binding to brain tissues from CD-1 mice is higher, with a free fraction of 6.7% (±1; n=3).

Kinase Assay: Enzymatic activity of PI3Kα is measured using a fluorescence polarization assay that monitors formation of the product 3,4,5-inositoltriphosphate molecule (PIP3) as it competes with fluorescently labeled PIP3 for binding to the GRP-1 pleckstrin homology domain protein. An increase in phosphatidyl inositide-3-phosphate product results in a decrease in fluorescence polarization signal as the labeled fluorophore is displaced from the GRP-1 protein binding site. PI3Kα is expressed and purified as heterodimeric recombinant protein. PI3Kα is assayed under initial rate conditions in the presence of 10 mM Tris (pH 7.5), 25 uM ATP, 9.75 uM PIP2, 5% glycerol, 4 mM MgCl2, 50 mM NaCl, 0.05% (v/v) Chaps, 1 mM dithiothreitol, 2% (v/v) DMSO at a 60 ng/mL concentration of PI3Kα. After assay for 30 min at 25°C, reactions are terminated with a final concentration of 9 mM EDTA, 4.5 nM TAMRA-PIP3, and 4.2 ug/mL GRP-1 detector protein before reading fluorescence polarization on an Envision plate reader. IC50s are calculated from the fit of the dose-response curves to a 4-parameter equation. Apparent Kis, where measured, are determined at a fixed concentration of ATP near the measured Km for ATP for PI3Kα, and are calculated by fitting of the dose-response curves to an equation for tightbinding competitive inhibition.

Cell Assay: For transport studies, cells are seeded on 24-well Millicell plates 4 days prior to use(polyethylene terephtalate membrane, 1 μm pore size) at a seeding density of 1.3×105 cells/ml). GDC-0084 is tested at 5 μM in the apical-tobasolateral (A-B) and basolateral-to-apical (B-A) directions. The compound is dissolved in transport buffer consisting of Hanks' balanced salt solution with 10 mM HEPES. Lucifer Yellow is used as the paracellular and monolayer integrity marker. GDC-0084 concentrations in the donor and receiving compartments are determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The apparent permeability (Papp), in the apical to A-B and B-A directions, is calculated after 2-hour incubation.

In Vivo

GDC-0084 markedly inhibits the PI3K pathway in mouse brain, causing up to 90% suppression of the pAkt signal. GDC-0084 achieves significant tumor growth inhibition of 70% and 40% against the U87 and GS2 orthotopic models, respectively. GDC-0084 distribution throughout the brain and intracranial tumors leads to potent inhibition of the PI3K pathway. It is being evaluated in patients, and exposures reached at tolerated doses are consistent with those associated with efficacious doses in mouse models.

Animal model

Male Sprague–Dawley rats or female CD-1 mice

Formulation & Dosage

Formulated in 60% PEG400/10% ethanol(i.v.) or 0.5% methylcellulose with 0.2% Tween 80(p.o.); 1 mg/kg (i.v.);5 or 25 mg/kg (p.o.); i.v. or p.o.

References

ACS Med Chem Lett. 2016 Feb 16;7(4):351-6; Drug Metab Dispos. 2016 Dec;44(12):1881-1889.